Main ongoing projects - IMPRES: Integrated Molecular Plant physiology Research

Abstract

My study aims to elucidate the role of reactive oxygen species (ROS) in regulating cell wall (CW) biomechanics during plant growth, a missing link in the growth regulatory pathway. Understanding this process is crucial for various aspects of plant biology including plant-pathogen interactions and stress responses. The research intends to integrate ROS signaling with CW integrity pathways to provide a mechanistic framework which could underpin future fundamental and agricultural development. I will use fast-growing root hairs of Arabidopsis thaliana as plant cell model to (1) quantify subcellular ROS dynamics and uncover its link with CW biomechanics, (2) study CW-ROS feedback regulation, (3) reveal the spatio-temporal dynamics of protein interactions involved in ROS-CW growth pathways, and (4) identify the ligands of ERULUS, a receptor-like kinase involved in CW integrity sensing. Dedicated work packages will make use of several interdisciplinary approaches that are present in the host-lab or through collaborations. These include the development of pH-insensitive cell wall-targeted ROS reporters, generation of crosses of mutants and transgenic lines, molecular modeling, ligand identification and characterization, and multiparametric live cell imaging experiments coupled to microfluidics. Overall, the research aims to provide a comprehensive understanding of the ROS-CW growth pathway, which could have significant implications for plant biology and agriculture.

Researcher(s)

• Promoter: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

How do animals, including humans, and plants cope with stress under altered environmental conditions (e.g., warming, drought), or in the presence of specific contaminants (e.g. PFAS, pesticides) originating from a variety of diverse sources? These are our main running research questions. In this biological/environmental research, it is crucial to trace and quantify different compounds of interest in a broad range of samples ranging from water, soil, and sediments over animal/human- and plant tissues. On the one hand, compounds of interest are hormones, which are well-known signal molecules altered in organisms during stress and being active in a very low concentration range. On the other hand, the ecotoxicological applications require research that keeps pace with the dynamic changes in the new generation of molecules used in industry and the evolution towards raised restriction levels in the environment determined by EU and local governments. Therefore, to claim a worldwide leading position in this field, it is important that we invest in the development of innovative sensitive analytical techniques which allow us to trace and quantify extremely low amounts of different compounds of interest. This project application aims to purchase a sustainable, new generation UPLC-TQD-MS, to improve the analytical platform available. This opportunity will not only support ongoing joint collaborations but will also bring the UAntwerpen to an acknowledged leading position in this field.

Researcher(s)

• Promoter: Prinsen Els
• Co-promoter: Bervoets Lieven
• Co-promoter: Covaci Adrian
• Co-promoter: Eens Marcel
• Co-promoter: Groffen Thimo

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The common denominator of the European Duckweed Network is duckweed or Lemnaceae. These small aquatic plants are not only the world's fastest growing flowering plants, they can produce a substantial amount of protein per hectare, considerably in excess of conventional protein crops. Furthermore, they take up nutrients, heavy metals, and nuclear contaminations from heavy polluted wastewater. These are all traits that make duckweed highly suitable to tackle European and global challenges such as food and feed production, bioremediation, or even combinations of both. Thus, duckweed can be a key part of a circular solution to the current sustainability crisis, for example by growing duckweed on pig manure waste, and subsequently using it as pig feed. The European Duckweed Network brings together key research experts from diverse fields such as agriculture, genomics, physiology, space research and nuclear science, and allows knowledge transfer on pilot and large-scale research on duckweed cultivation. Despite the differences in background, all network partners share a common aim, to develop duckweed cultivation for a more sustainable future. It is also recognized by the partners that open communication and knowledge exchange is necessary to achieve this. This way, common challenges such as optimizing harvesting techniques, improved crop protection (against algae, black water lily aphids, and pythium), and reduced plant stress (nutrient imbalances, and climatic conditions) can be systematically tackled, optimally using the multidisciplinary expertise that is present in the network.

Researcher(s)

• Promoter: Asard Han
• Co-promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

During growth, plant cell walls are sufficiently strong to resist turgor pressure and avoid lysis, yet at the same time they need to be extensible for growth. To explain this dual functionality, we need to understand how cells perceive the rheological status of their cell walls and how they, in turn, adapt the wall growth capacities. The ENDOPOL project builds upon recent findings of both promotors' labs on root hairs, showing that a plasma membrane-localized receptor-complex (LLG-CrRLK1Ls), together with secreted Rapid Alkalinization Factors (RALF proteins) and Leucine-rich repeat extensin-like (LRX) proteins serve as 'cell wall integrity sensing module' and link cell wall status to cytoplasmic signalization fine-tuning wall rheology. Preliminary data suggests a controlling role of endocytosis in this process. Using state-of-the-art microscopy and molecular biology approaches we will reveal 1) the module member dynamics and localization towards each other at the submicron to nano-scale, and in relation to pectin organization, 2) how endocytosis is embedded and regulated within the cell wall integrity module, 3) RALF-perception with high spatial resolution, and 4) factors involved in downstream RALF-CrRLK1Ls signaling. This project combines the strengths of both labs and aims a mechanistic understanding of how the organization, interaction and dynamics of the involved proteins relate to the fast and nanoscale changes in cell wall/pectin status that control growth.

Researcher(s)

• Promoter: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

A major challenge in sustainable agriculture is to secure crop productivity under adverse environmental conditions in order to match the growing world population. Plants are exposed to multiple abiotic stresses such as submergence – an increasing problem due to global climate change – and cadmium accumulation in soils, resulting in important crop losses. The phytohormone ethylene is known to be a crucial player in stress control. Apart from being the direct precursor of ethylene, the non-proteinogenic three-membered ring alpha-amino acid ACC, occurs as different metabolites in planta and acts as a signaling molecule independent of ethylene. This project aims to unravel how and under which form ACC regulates normal plant growth and the responses to flooding and heavy metal stress.

Researcher(s)

• Promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

In addition to the growth promoting interactions between the soil microbiome and plants there is growing evidence that areal plant tissues have their own microbiome of endophytes. Several of these stimulate growth under optimal or limiting conditions, providing a potential for a sustainable enhancement of crop productivity, but how they affect the growing tissues is largely unclear. The aim of the proposed research project is to study the effects of endophytic fungi and bacteria on maize leaf growth regulation under optimal and drought conditions. Endophytic bacteria and fungi isolated from the leaf growth zone of grasses growing in arid conditions will be functionally characterised using a multidisciplinary approach. This will involve culturing and in planta testing of isolates for their effect on leaf growth under optimal and drought conditions. The genome of growth promoting isolates will sequenced, annotated and phylogenetically analysed. Functional analysis of the endophytes in planta will include kinematic analysis of cell division and expansion in the leaf growth zone, flowcytometry, NGS sequencing (plant and endoyphytic mRNA), metabolome analysis and quantification of endophyte numbers under control and drought conditions. The impact of the plant on endophyte development will be tested by comparing the colonisation and growth effects in maize varieties and selected mutants.

Researcher(s)

• Promoter: Beemster Gerrit
• Co-promoter: Abd Elgawad Hamada

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Following the nuclear accidents in the Chernobyl (1986) and Fukushima Dai-Ichi (2011) nuclear power plants, vast areas of land were contaminated with radionuclides, leading to a long-term exposure of the environment to enhanced levels of ionizing radiation. In the forests near the Chernobyl reactor, some of the Scots pine trees (Pinus sylvestris) that received a sub-lethal dose of radiation began to portray morphological changes resembling those seen when a plant loses its apical dominance, i.e. growth of the pine trees from two or more emerging branches instead of growing along a single primary trunk as usual. Similar abnormal growth patters were recently observed in young Japanese red pine (Pinus densiflora) in the Fukushima Exclusion Zone. The mechanisms behind the radiation-induced morphological abnormalities in these plants has up to date not been elucidated. However, it is known that plant hormones, specifically cytokinins and auxins, play important roles in cell division and cell differentiation during growth of the plant apex, thereby dictating the plant's growth habit. More recently, a strong correlation has been observed between auxin accumulation and DNA methylation. There is also evidence that radiation can induce changes to DNA methylation in plants. In light of these findings, we suggest that radiation leads to a disturbed hormone balance or transport which in turn leads to morphological changes in Pinus sylvestris. It is also proposed that changes to DNA methylation may lie at the basis of the disturbance of the plant hormone metabolism. In collaboration with the Belgian Nuclear Research Centre, these hypotheses will be investigated by providing answers to the following research question: 1. To what extent do the hormone balances contribute to the changed phenotype observed in P. sylvestris after exposure to ionizing radiation? 2. How do the proteome and the transcriptome of P. sylvestris respond after exposure to ionizing radiation 3. Do changes in DNA methylation or in the activity of transposable elements contribute to the observed responses in P. sylvestris? Taken together, the findings obtained during this PhD project can shed light on the abnormal growth patterns seen in irradiated pine trees, thereby giving fundamental insight on the effects of radiation on plant growth.

Researcher(s)

• Promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

At the Department of Biology at the University of Antwerp, techniques for detailed monitoring of Arabidopsis thaliana root hair development and detection of their growth, have been refined and made available for the study of regulatory pathways and mechanisms. These techniques include the optimized growth of Arabidopsis thaliana plants for high quality root hair development, the use of confocal microscopy for detection of fluorescent fusion proteins in localization studies, and a procedure for quantifying the external pH oscillations of root hairs. Together, these techniques can reveal possible up or down regulation of the plasma membrane H+-ATPases (AHAs), that are essential for maintaining an electrochemical gradient of protons in plant cells, that in turn drives secondary active transport processes across cell membranes. In this specific collaboration, these techniques are applied for phenotyping of root hairs of AHA and ERULUS receptor kinase mutants relative to wild type plants. Also, the root hair localization of the AHA2 and AHA7 mutant pumps are examined.

Researcher(s)

• Promoter: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Plants grow towards areas favourable for their survival. This is the result of individual cell growth. The latter can only occur when the cell wall, which surrounds plant cells, is not too stiff, yet not too loose. This requires constant monitoring of cell wall biomechanics. How cells sense and control cell wall biomechanics during growth is the central theme of this project. Plants have evolved proteins to monitor and respond to changes in cell wall properties. Members of the 'Catharanthus roseus Receptor-Like kinases 1-Like' (CrRLK1L) protein family serve as cell wall composition sensors during cell growth. In Arabidopsis t. we identified the CrRLK1L ERULUS (ERU), which controls cell wall composition and pectin (cell wall component that controls flexibility) dynamics during root hair growth, presumably together with FERONIA (FER), another CrRLK1L. To understand how cell wall biomechanics are regulated during cell growth we will study (1) the relation between pectin modification and root hair growth, (2) the cell wall properties of ERU and FER mutants, (3) which signals are perceived by ERU and FER, and (4) the functional relation between cell wall pH, pectin, RALFs (cell wall localized small peptide CrRLK1L ligands), Ca2+, ERU and FER signaling in regulating cell growth. Our results will provide an integrated view on the processes that control cell wall biomechanics during cell growth, using ERU and FER root hair growth as a model.

Researcher(s)

• Promoter: Vissenberg Kris
• Fellow: Schoenaers Sébastjen

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Early spring cold is a major limiting factor for maize cultivation in North-Western Europe. Typically, cold spells are only transient and it is known that the capacity of varieties to recover strongly determines their final yield. Nevertheless, in contrast to the direct response to adverse conditions, the mechanisms involved in the recovery of growth have scarcely been studied. This project addresses this critical lack in our knowledge, using an innovative experimental setup where transient exposures to cold are applied at different stages of the development of the 4th leaf of maize lines with contrasting cold tolerance. Advanced phenotyping will be used to quantify the effect on the elongation growth of the leaf, during the cold and upon recovery until the leaf stops growing. Kinematic analysis will be used to quantify the cellular basis of the growth response and recovery. We will determine the molecular changes in the leaf growth zone during the response and recovery phase by means of mRNA sequencing, antioxidant and carbohydrate metabolites analysis and biochemical assays. At the physiological level we will determine the response of photosynthesis and water-relations. Based on this comprehensive and integrated analysis, candidate recovery genes will be identified and mutant and transgenic lines with altered expression of these genes will be acquired and studied in our experimental setup and under field conditions. The obtained knowledge will be scientifically innovative and relevant for plant breeding.

Researcher(s)

• Promoter: Beemster Gerrit
• Co-promoter: Abd Elgawad Hamada
• Fellow: Lainé Cindy

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Plant cell growth ultimately relies on controlled loosening/strengthening of the cell wall, yielding a matrix that is not too stiff, yet not too loose. Plants have evolved specific mechanisms to sense and control cell wall composition and rigidity, in the form of cell wall binding receptor proteins. In this regard, the Catharanthus roseus Receptor-like Kinase 1-like (CrRLK1L) family of plant proteins has gained major attention during recent years. Several CrRLK1L proteins control cell growth through sensing of the cell wall status during expansion. Nevertheless, the mechanisms that lie at the basis of CrRLK1L-mediated signaling remain poorly understood. In an effort to further characterize CrRLK1L-functioning we identified ERULUS (ERU), a key regulator of root hair cell expansion, and a putative sensor of cell wall rigidity. ERU loss-of-function root hairs are short an stunted, and exhibit drastic defects in cell wall composition, pectin (a cell wall polysaccharide) modification and dynamics. The degree of pectin methylesterification directly relates to the degree of cell wall rigidity. Hence, pectin modification needs to be sensed and adjusted continuously to facilitate maintained cell growth. The ERU extracellular domain is highly similar to that of the CrRLK1Ls BUDDHAS PAPER SEAL 1/2 (BUPS1/2), which directly bind pectin in vitro. More so, ERU control of root hair growth involves the CrRLK1L FERONIA (FER), which also directly binds pectin. Together, these data provide a strong case for a direct ERU-cell wall interaction. Here, we propose to use a broad-spectrum carbohydrate array to screen for ERU-specific cell wall ligands. This method has previously been used to identify/characterize antibody specificity, carbohydrate binding modules and cell wall modifying enzymes. The procedure involves cloning and heterologous expression of a His6- and GST-tagged ERU extracellular protein domain, and subsequent array analysis using a bacterial lysate containing the soluble recombinant protein. The protocol is low-risk, simple and affordable (no protein upscaling and purification). Moreover, the tagged protein construct can be used for several downstream applications aimed at identifying protein-protein and protein-cell wall interactions. This experiment will be performed during a 2 months research stay, and will bring new expertise to the IMPRES group. Moreover, the outcome of this experiment is pivotal to our ongoing research and crucial to the understanding of cell wall sensing during plant cell growth.

Researcher(s)

• Promoter: Schoenaers Sébastjen

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The main function of plant roots is to forage for soil resources. Root hairs, tubular extensions of the root's outer cell layer, represent 70% of the root surface area and are the primary site of water and nutrient uptake. When grown in specific soil conditions, mutants with shorter root hairs have reduced plant fitness. Understanding how factors like the plant hormone auxin control root hair development are therefore critical to optimise agricultural systems with respect to water and fertilizer use. The data are disjointed and an integrated view is lacking. We will use the model plant Arabidopsis and our recently published mutant that grows shorter root hairs. The expression of the mutated gene, ERULUS, is directly controlled by auxin and normally encodes a kinase, a protein that regulates its targets' activity by phosphorylation. Changes in specific cell wall enzyme activity, modifying pectins, causes strongly reduced root hair growth in the mutant. Our aim is to elucidate the pathway that starts from auxin, involves ERULUS and cell wall metabolism and results in normal root hairs. We identified 3 objectives that concentrate on different levels: i) Unravelling the control of ERU expression by auxin ii) Characterization of ERU protein functionality iii) Elucidation of ERU-mediated control of root hair growth through specific cell wall enzymes The data gathered during these 3 work packages will allow me to interconnect pathways up- and downstream of the identified ERULUS kinase and it will probe auxin regulation throughout the root hair expansion network.

Researcher(s)

• Promoter: Vissenberg Kris
• Fellow: Claeijs Naomi

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project aims to understand the molecular mechanisms underlying the therapeutic effect of cinnamaldehyde (the active constituent of a novel drug of gestational diabetes). We will be using Next Generation Sequencing (NGS), expression analysis and biological interpretation by means of clustering, overrepresentation and pathway analysis. This will also help us to identify new effective signalling molecules.

Researcher(s)

• Promoter: Beemster Gerrit

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Drought is the most limiting factor for crop yield and ecosystem productivity and is predicted to become more prevalent in light of global climate change. One of the first responses of the plant to drought is an inhibition of leaf growth. This is the result of an inhibition of the growth of cells in the growth zone of the leaves. The growth of cells is a driven by a hydrostatic pressure (turgor) generated inside the cells, but is largely controlled by varying the reversible (plastic) and irreversible (elastic) extensibility of the wall. This project aims to further our understanding of the regulation of this crucial process. To this end, we developed a new assay where we measure the extension dynamics in different parts of the growth zone of control and drought stressed leaves after increasing the turgor. Additionally, we determine turgor in unperturbed segments using Psychometry. The extensibility measurements will be validated by independent methods: Atomic Force Microscopy to determine turgor and cell wall elasticity and extensiometry to determine cell wall plasticity. The assays use live tissues in a watery solution. Therefore, we can add putative regulatory substances, H2O2, Abscisic acid, sugars and change the pH to test their effect. These substances are of interest as we have shown that their levels in the growth zone are strongly affected by drought and they have been linked in the literature with the regulation of cell expansion. This project will yield a clear insight in the mechanistic basis of the drought response and its regulation, providing a basis to develop more tolerant crop varieties.

Researcher(s)

• Promoter: Abd Elgawad Hamada

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Plants need light to grow and how plants regulate growth in response to light is the central theme in this project. Light drives the generation of sugars by photosynthesis and sugars act as signalling molecules that regulate developmental processes including cell division and expansion. Studies on growth regulation by sugars have been done largely in Arabidopsis, but we use the maize leaf due it its larger size that allows to performe analyses of the sugar metabolism, particularly in proliferating and expanding cells that drive growth. Our preliminary data show that shading mature leaves inhibits growth of younger leaves, but shading the mature part of the growing leaf stimulates growth. Also 4 mutations of sugar metabolism genes affect leaf growth. To understand how this regulation works we study to what extent sugar is transported from source leaves and from the mature part of growing leaf (by studying transport of radioactive 11CO2 fed to different leaves. How this sugar regulates leaf growth at cellular (cell division and expansion), metabolic (different sugars and hormones); biochemical (enzyme activities) and transcriptional (mRNA )levels in the growth zone at the base of the leaf. Our combined results will lead to new knowledge about the mechanism linking genetic, molecular, cellular and physiological levels to whole organ growth rates, which can be used to improve the growth of crop species in the context of changing climate conditions.

Researcher(s)

• Promoter: Beemster Gerrit
• Fellow: Abd Elgawad Hamada

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The major share of research on maize leaf growth focuses on the impact of environmental factors. Despite their importance, these data are limited for the understanding of key regulatory components in leaf growth. Therefore, our laboratory has identified 5 unique long leaf maize lines through screening and selection of chemically mutated maize lines. Consequently, the objective of this project is the characterisation of 3 long leaf mutants to improve our understanding in leaf growth regulation. Firstly, we will try to appoint the (single) mutation that causes the long leaf phenotype. We must validate whether the hypothesised mutation indeed causes the observed long leaf phenotype by selecting/creating an independent line with a mutation in the hypothetical gene. Next to this, we will evaluate whether the mutation affects the expression of certain genes/pathways. Secondly, there is a need for a more extensive examination of the longleaf phenotype. This will be done at the cellular level (where cell division and expansion, both defining leaf growth, will be determined in more detail) and at the whole-plant level. Finally, the outcome of the previous experiments will result in new information on which we can base targeted cellular analyses, metabolite and enzyme measurements.

Researcher(s)

• Promoter: Beemster Gerrit
• Fellow: Sprangers Katrien

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Metal contamination is a major environmental concern in many industrialized and developing countries since metals enrich in the food chain, creating threats for human and animal health. Metal-risk assessments in soil are mostly based on the effects of single metals, while contaminated soils are frequently characterized by multi-metal contaminations. Even though metals may cause no or very limited observable effects when applied individually, the combination of different chemicals can produce significant toxic effects. There is thus an increased need to understand how metals act together in mixtures and how these should be handled in regulatory risk assessment. Plant toxicity tests mainly use 1 metal and assess general endpoints and often do not provide any insight into the effect on the underlying biological processes that lead to the observed effects, making comparison of the effects of different metals, supplied as singles or mixtures, difficult. We will use Arabidopsis as model plant to perform analysis of the effects of Cd, Cu and Zn at the transcriptome, proteome, metabolome and cellular physiology level using state of the art technology. This systems biology approach will allow us to integrate the data obtained at the different organisation levels of the root and to create a series of events in order to explain the observed effect of metal addition on Arabidopsis root growth. This formation of an 'adverse outcome pathway', used for animal systems, is novel for plants.

Researcher(s)

• Promoter: Vissenberg Kris
• Co-promoter: Blust Ronny
• Fellow: Kranchev Mario

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Aluminum (Al) is an important toxic heavy metal, considerable reducing plant growth and crop production, in particular in acidic soils, worldwide. Rye (Secale cereale), is a crop particularly known for its tolerance to acidic soils, and to Al. Therefore, understanding the Al-tolerance mechanism, at the molecular, mechanistic level, will provide a basis for tolerance-improvement, also for other crops. Previously (3 years PhD work by the candidate), two rye genotypes were used, Beira and RioDeva, respectively more tolerant and more sensitive to Al, to unravel the underlying molecular mechanisms. Young rye plants were exposed to sub-lethal doses of Al, for short periods of time (24, 48h), and analyzed at multiple organizational levels. Analyses included photosynthesis, antioxidant metabolism, and several other defense responses. The analysis demonstrates that there are differences at the molecular level, between the genotypes, and differences in response to Al, at the level of defense responses. This work has been performed by the candidate at the University of Porto in collaboration with the IMPRES group at the University of Antwerp. The aim of the DocPro-project, is to deepen the understanding of Al-tolerance in rye, by expanding on the results obtained so far, with expertise at the University of Antwerp (IMPRES laboratory, prof. H. Asard & prof. G. Beemster). The specific objectives of this project are 1) the identification of the cellular basis of the growth response in the leaf growth zone (i.e. meristematic zone and elongation zone), through kinematic growth analysis. This identification will be used to analyze, zone-specific, biochemical and molecular responses to Al. And 2), a genome-wide transcriptome-level analysis (through Next Generation Sequencing) of the Al-response in each genotype. This will result in identification of molecular responses to Al that mediate the whole organ growth response, and which will be of interest for future basic and applied research. The overall work on Al toxicity by the candidate, is novel in that it focusses on acute Al toxicity in rye seedlings, and applies genotype-comparison to unravel tolerance mechanisms. Two elements contribute to guaranteeing the successful outcome of this project, i.e. 1) the work performed so far (in Portugal) will result in 3 publications (A1), and, by itself, could be sufficient to obtain a PhD at the home institution. 2) the expertise of the IMPRES laboratory, fits seamless to the previous work of the candidate, and is a natural extension that will result in a joint PhD and an additional high-impact publication.

Researcher(s)

• Promoter: Asard Han
• Fellow: De Sousa Alexandra

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Pollution with cadmium (Cd) caused by historical industrial activity is a serious problem in the Campine region of Belgium. Cd inhibits plant growth and understanding this response may facilitate the growth of plants on polluted soils, its accumulation in and harvest of Cd-containing plant biomass. From a scientific point of view, the response of plant growth to Cd exposure is interesting, as it perturbs specific regulatory mechanisms, including cell cycle regulation, cell wall chemistry and redox regulation. Thereby, the role of these processes in organ growth regulation can be unravelled. By studying the maize leaf growth zone we can combine kinematic analyses of cell division and expansion rates with molecular and physiological studies that are not feasible in the model species Arabidopsis. Using both short- and long-term Cd exposure allows us to unravel signalling events and regulatory interactions in growth regulation. The effects on cell division will be further analysed by flowcytometry and on expansion by measuring cell wall extensibility. The underlying molecular mechanisms will be studied in each zone (division, elongation and maturation) at the transcriptome, metabolite and enzyme levels. Initially, wild-type maize lines are used. Based on the obtained results, mutants perturbed in key pathways will be studied. All data will be integrated using bio-informatics, so that a holistic view of growth regulation in general and its response to Cd in particular is obtained.

Researcher(s)

• Promoter: Beemster Gerrit

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project aims to increase our knowledge on the regulation of plant cell elongation, as it shapes plant size and form and determines primary biomass production. Arabidopsis thaliana will serve as model plant and the hypocotyl will be used to identify key-players in the regulation of (cell) elongation. The hypocotyl's elongation is very prominent in the dark, but upon perception of light, elongation is rapidly inhibited. We have identified and phenotyped a unique mutant, apollo, that fails to inhibit elongation in the light, but that shows all other signs of de-etiolation. In order to identify genes and miRNAs with a crucial role in the light-regulation of cell elongation we will compare the transcriptome of 1) dark-grown wild-type with dark-grown apollo, 2) light-grown wild-type with light-grown apollo and 3) dark-grown wild-type but transfered to light with dark- grown apollo but also transfered to light using Next Generation Sequencing (NGS). In addition, the mutant results in the sustained up-regulation of a transcription factor (ORPHEUS) that in wild-type seedlings is down-regulated upon light preception, identifying it as a potential switch to regulate expansion and inhibition of expansion. Therefore, we will identify the target genes of this transcription factor using NGS on DNA that results from chromatin immunoprecipitation. A functional analysis with a reverse genetic approach will link the individual genes to their function and role in the expansion-regulation.

Researcher(s)

• Promoter: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

In a recent screen of segregating mutant lines in the field, our laboratory identified 35 maize mutants with an increased leaf size. I have confirmed 5 of these with the strongest phenotype under controlled growth room conditions. Unlike other model species the maize leaf growth zone is large enough to harvest samples across the gradient of dividing, expanding and mature cells for a wide range of molecular and physiological analyses. Therefore these mutants provide a unique opportunity to generate new insights into the mechanisms by which plants regulate organ growth. The objective of this project is to mechanistically understand the phenotype of 3 of these mutants by: -Mapping the mutation that causes the longleaf phenotype. To validate whether the identified mutations indeed cause the observed longleaf phenotype we will select/create independent lines with a mutation in the same gene. -Perform genome-wide transcriptome analysis to identify which genes and pathways are affected by the mutation. -Determine the cellular basis (cell division and expansion) of the phenotype and study the effect of the mutation on other parts of the plant. -Perform physiological, metabolite and enzyme measurements focusing on specific regulatory pathways identified by the above analyses. The obtained results will give us a more integrated understanding of the key regulatory processes in leaf growth and size determination.

Researcher(s)

• Promoter: Beemster Gerrit
• Fellow: Sprangers Katrien

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Native rice cultivars of Argentina show strong difference in cold tolerance. In the context of her running PhD project, the candidate has shown that this is related to differences in physiological parameters, particularly related to photosynthesis and water use efficiency. Currently, she is performing a transcriptome analysis and a metabolite analysis to investigate differences in gene expression and selected metabolic pathways between lines with contrasting cold tolerance. The proposed project at the UA aims to complement these analyses with a kinematic analysis of cell division and expansion in the growing rice leaves of contrasting lines growing under optimal and cold conditions to understand the cellular basis of the growth effects and subsequently perform a proteome analysis of the leaf growth zone using the iTraq approach recently established in the host group.

Researcher(s)

• Promoter: Beemster Gerrit
• Fellow: Gazquez Ayelén

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This research project aims at developing new neutraceuticals to be used as food or feed supplements for human and veterinary use. This research has a dual aim: i) the identification and characteisation of active biomolecules in a fermented plant protein (Lianol®), and ii) the validation of the analytical methods and biomarkers to define the biological activities of these active molecule(s).

Researcher(s)

• Promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

in this project we will study the effects of UV-B exposure on differential growth in the model plant Arabidopsis. We will investigate whether the UVB light gradient leads to a functional gradient, that eventually controls flavonoid accumulation and control hormonal responses and differential elongation. Molecular physiological, genetic and biochemical methods will be used.

Researcher(s)

• Promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project aims to increase our knowledge on the regulation of plant cell elongation, as it shapes the size and form of plants and plays a key-role in the primary production of biomass. The elongation of the dark-grown Arabidopsis hypocotyl occurs only through cell elongation, making the hypocotyl an ideal model to study (regulation of) cell elongation. One of the prerequisites for this etiolated growth is the deposition of a thick cell wall during the slow growth phase, which becomes extensively remodelled and thinned during expansion. Furthermore, hypocotyl elongation is rapidly inhibited when light is perceived.

Researcher(s)

• Promoter: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand the Univ. of Copenhagen. UA shall contribute to the project under the conditions as stipulated in the present contract.

Researcher(s)

• Promoter: Markakis Marios Nektarios

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand Erasmus Mundus. UA provides Erasmus Mundus research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: Beemster Gerrit

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The project will further investigate the collection of 10 new maize mutants, which all have increased leaf size phenotypes under field and growth chamber conditions. The overall aim is to identify the mechanisms underlying the observed phenotype at the leaf, whole plant and crop level.

Researcher(s)

• Promoter: Beemster Gerrit

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Two kinases and one kinase-interacting protein were identified using 2 microarray datasets of root hair mutants coupled to a comprehensive reverse genetics approach. The project aims to reveal how they are regulated by auxin and how they regulate tip-growth in root hairs. This can be summaried by the following objectives: 1) The genes are auxin-regulated in an auxin response factor-dependent manner (ARF7/ARF19). Chromatin ImmunoPrecipitation (ChIP) followed by gene-specific PCRs will reveal whether they are direct or indirect targets of these ARFs (Dr. Hill, Nottingham Univ.) and qPCR will quantify their expression levels in several auxin-signaling mutants, further unraveling their auxin-regulation. 2) The involvement of the genes in NADPH oxidase-dependent, auxin-regulated ROS accumulation in root hairs will be monitored. This study involves molecular biological techniques and different forms of microscopy. 3) With the use of ion-specific vibrating probes and ion-sensitive dyes coupled to ratio-imaging, the effect of the gene knock-outs on extracellular ion-fluxes and intracellular ion-gradients at the growing tip root hairs - a conditio sine qua non for sustaining tip-growth - will be quantified (Prof. Feijó, Lisbon Univ.). 4) The interaction partners/targets of the proteins will be identified using tandem affinity purification (Dr. De Jaeger, Gent), followed by kinase assays. T-DNA insertion lines for the identified interaction partners will be screened for root hair (and pollen tube growth) phenotypes. Together, these objectives will clarify how auxin regulates these genes and how these genes, in turn, regulate tipgrowth in root hairs (and pollen tubes)/

Researcher(s)

• Promoter: Vissenberg Kris
• Fellow: Schoenaers Sébastjen

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Hormone action was until recently mainly viewed as an organ-specific process. Based on recent findings for auxins, gibberellins and brassinosteroids, we speculate that cell type specificity plays a general role in hormone action mechanisms. In this project, cell type specificity of ethylene action will be addressed by using cell type specific promoters driving EBF1 and EBF2 (EIN3 binding F-box 1 and 2), two regulators of the prevalence of the EIN3/EIL1 proteins, positive regulators of ethylene signaling.

Researcher(s)

• Promoter: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project represents a research agreement between the UA and on the onther hand IWT. UA provides IWT research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: Prinsen Els
• Fellow: Jhaveri Ashka

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

In this network, we want to investigate how root and shoot influence each other and how this interaction contributes to the development of the plant. Such an intergrated approoach represents a realistic potential to identify major plant growth controlling components, therefore we aim to transfer this knowledge to the crop species maize.

Researcher(s)

• Promoter: Beemster Gerrit

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Based on the transcriptome data the project aims to generate a gene regulatory network leading to root bending and to unravel the role and function of several of the identified genes in the bending response. This will be achieved by in silico analysis of the available data and a detailed analysis of the expression pattern, of the effect of gene-overexpression, of the location of the gene product and possible interaction partners.

Researcher(s)

• Promoter: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This is a fundamental research project financed by the Research Foundation - Flanders (FWO). The project was subsidized after selection by the FWO-expert panel.

Researcher(s)

• Promoter: Prinsen Els
• Fellow: Van Elst Daan

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand a private institution. UA provides the private institution research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: Guisez Yves

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand Erasmus Mundus. UA provides Erasmus Mundus research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: Beemster Gerrit

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Developmental processes involve a complex network of interactions between multiple regulatory processes that traditionally are studied separately. We propose a systems biology approach, whereby experimental biologists closely interact with mathematical modellers, to unravel the functional relationships between auxin signalling, cell division and expansion and whole leaf morphogenesis.

Researcher(s)

• Promoter: Beemster Gerrit
• Co-promoter: Broeckhove Jan
• Co-promoter: Prinsen Els
• Co-promoter: Vanroose Wim
• Co-promoter: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Based on at least 5 separate micro-array studies many genes differentially expressed between a control and a mutant/ treated organ/different time point were identified. In a first step available T-DNA knock-out or knockdown lines were analysed and those with a growth phenotype were selected for further detailed study. This involves a) spatiotemporal gene expression analysis, b) monitoring the effect of elevated and decreased gene expression levels on growth, c) identifying the location of the gene product and d) revealing interference with known developmental pathways. Especially a) and b) require detailed knowledge on gene expression levels and the time course of changes in these levels by several treatments.

Researcher(s)

• Promoter: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The MOMEVIP partners will integrate competences in ecology, physiology, biochemistry, molecular biology, functional genomics and bioinformatics to improve knowledge about the molecular and metabolic bases of VIP biosynthesis, and the functions of VIP (isoprene, monoterpenes and sesquiterpenes, collectively) in plant protection, per se and when interacting with other defensive pathways.

Researcher(s)

• Promoter: Asard Han
• Co-promoter: Beemster Gerrit
• Co-promoter: Janssens Ivan
• Co-promoter: Nijs Ivan

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

system to investigate the molecular and cellular basis of plant growth responses to drought. By means of kinematic analysis we found that cell division in the basal 2 cm and cell expansion in the next 5 cm are inhibited. In this project we propose to perform a genome-wide study of the molecular changes associated with this inhibition of the growth process and, additionally, we will specifically focus on redox homeostasis. The genome-wide analysis involves a microarray and a proteome study, where we will sample meristem, elongation zone and mature tissue under control conditions and different levels of drought. For the redox studies we will use the spatial gradient along the leaf to measure redox capacity, the level of the major antioxidants and the expression level and activity of key regulatory enzymes. This will be done in wild-type plants subjected to different levels of stress and in mutants that are defective in redox enzymes. All essential equipment and personnel for the proposed experiments is available in the research group, only consumables are needed to be able to execute them.

Researcher(s)

• Promoter: Beemster Gerrit

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project will produce mathematical models of root development in Arabidopsis thaliana integrating the molecular regulation of cell division activity, cell elongation and transport of hormones with growth and architectural and mechanical characteristics of roots.

Researcher(s)

• Promoter: Vissenberg Kris
• Fellow: De Vos Dirk

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Since several years Bayer BioScience generated epigenetically altered agricultural important plant species such as e.g. Brassica napus. These lines differ between each other in different traits such as yield, stress tolerance but also in respiration, gene expression, histone modification, etc... We further characterize these lines in collaboration with Bayer BioScience and VIB (UGent). The aim of our research group is to characterize the proteomes and the differences between the different lines and to study histone modifications making use of the iTraq, 2D-LC and mass spectrometry .

Researcher(s)

• Promoter: Guisez Yves

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand EU. UA provides EU research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: Beemster Gerrit

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project will evaluate the effects of predicted climate change factors (elevated CO2 and temperature) on plant growth, plant physiology and biochemical responses related to oxidative stress

Researcher(s)

• Promoter: Asard Han

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

We will functionally analyze Zea mays mutants for their response to abiotic stress conditions. This will be done using kinematic analysis of cell division and expansion and RT-PCR expression analysis.

Researcher(s)

• Promoter: Beemster Gerrit

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The Arabidopsis hypocotyl has two growth phases. During the first phase, all cells grow slowly and synchronous and they are 'prepared' to start the second phase. During the fast asynchronous growth, cells elongate dramatically. Based on micro-array results specific differentially expressed genes that allow cells to start and proceed through the second growth phase are studied.

Researcher(s)

• Promoter: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This is a fundamental research project financed by the Research Foundation - Flanders (FWO). The project was subsidized after selection by the FWO-expert panel.

Researcher(s)

• Promoter: Prinsen Els
• Fellow: Van Elst Daan

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The project aims to study the role of genes in the development of Arabidopsis roothairs. 151 genes were identified, many having a role in cell wall metabolism. The phenotype of knock-out plants will be investigated, as well as cell wall composition, expression patterns, the effect of overexpression on the phenotype and the localisation of the geneproducts of interesting genes. If necessary, interesting lines will be crossed into mutant backgrounds or in plants with fluorescent markers.

Researcher(s)

• Promoter: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The aim of the project is to develop a 3-D mathematic simulation model of inter-actions at the molecular, cellular and organ level during leaf growth in Arabidopsis thaliana. We will start from an existing 2-D model of vascular development that was build in the previous research group of the Promotor. This model will be extended to include multiple cell layers and modules for cell division and expansion.

Researcher(s)

• Promoter: Beemster Gerrit
• Co-promoter: Broeckhove Jan
• Co-promoter: Vanroose Wim

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

TAP (tandem affinity purification) technology allows us to study in vivo protein interactions (e.g. in planta). The plant extracts are prepared by VIB (Flemish Institute for Biotechnology, Ghent, Belgium) for a biotechnological company. The proteins composing the protein complexes are identified using mass spectrometrical measurements generated by MALDI TOF/TOF (within the core facility CeProMa, Centre for Proteome Analysis and Mass spectrometry, UA).

Researcher(s)

• Promoter: Guisez Yves

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The aim of this project is to identify and functionally characterize new genes and regulatory pathways that play a role in the response of Arabidopsis thaliana to drought stress. In collaboration with the Vision lab we will develop an automated image analysis platform that will allow quantification of number, composition and size of cells in cleared leaves of 75 Arabidopsis genotypes. The most promising lines will be analyzed in more detail.

Researcher(s)

• Promoter: Beemster Gerrit

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The size and form of plants largely depend on the process of expansion that follows cell formation in the meristems. Using data from several available micro-array experiments the project aims to study genes with a function in the elongation of the Arabidopsis root. A reverse genetics approach coupled to an in depth analysis of the genes will reveal their precise role in the elongation process.

Researcher(s)

• Promoter: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The role of the growth regulating plant hormone auxin in the response to abiotic stresses such as drought has hardly been investigated to date. Based on micro-array data we have strong indications that the expression of 45 auxin response genes is specific for dividing cells and is strongly affected by drought. In this project mutants for these genes will be isolated and tested for their effect on growth under optimal and drought conditions.

Researcher(s)

• Promoter: Beemster Gerrit

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The main aim of the project is to advance our knowledge in the evolution and function of bacterial leaf symbiosis within Rubiaceae by addressing the following questions: 1. When and how did bacterial leaf symbiosis originate in different Rubiaceae genera? 2. How strict is the congruence between the phylogeny of host plants and their endosymbionts? 3. At what level and through which mechanisms do bacterial leaf symbionts provide advantages to plants or vise versa?

Researcher(s)

• Promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project represents a research contract awarded by the University of Antwerp. The supervisor provides the Antwerp University research mentioned in the title of the project under the conditions stipulated by the university.

Researcher(s)

• Promoter: Guisez Yves
• Co-promoter: Lambeir Anne-Marie
• Co-promoter: Lemière Filip
• Co-promoter: Maes Bert
• Co-promoter: Maes Louis
• Co-promoter: Moens Luc
• Co-promoter: Van Ostade Xaveer

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project aims to evaluate the impact of increasing tropospheric ozone pollution on changes in antioxidant and glucosinolate (natural toxin) composition of Brassica species. These are important factors in relation to health and safety aspects of the food and feed chain. Objectives : 1. to determine the impact of increasing tropospheric ozone concentrations on antioxidant and glucosinolate composition of Brassica species. 2. evaluation of the influence of ozone on the human diet and animal feed intake by incorporating the changes in antioxidant and glucosinolate levels in the food chain 3. to identify physiological and biochemical biomarkers for ozone stress by investigating the interaction between stress induction and changes in secondary metabolites. 4. elucidation of interaction between abiotic stress induction, defence pathways and changes in secondary metabolites by means of transcriptoom analysis 5. evaluation of impact of ozone induced changes in glucosinolate content and composition in relation to plant-pathogen/insect interaction through literature study 6. to determine yield losses and changes in yield quality 7. to contribute to ozone flux modelling by providing data on environmental dependence of stomatal conductance of oilseed rape and broccoli. To achieve the main objective, oilseed rape or canola (Brassica napus L.) and broccoli (Brassica oleracea L. cv. Italica) will be exposed to different levels of ambient ozone concentrations during their entire growth. The experiments will be performed under «near-field» conditons in 15 Open-Top Chambers (OTCs) at the Veterinary and Agrochemical Research Center (VAR) in Tervuren and be repeated over 3 consecutive years to ensure sufficient environmental variation for data extrapolation. Comparison with unframed «open¿field» plots enables determination of the variation in ozone flux at the leaf level under fluctuating climatic conditions (soil moisture, air humidity, temperature, global radiation). The Research Group of Plant and Vegetation Ecology of the University of Antwerp is responsible for the physiological assessments of plant heath throughout the experiments. This will be achieved through measurements of gas exchange and chlorophyll fluorescence at the leaf level. The main objective of these measurements is to identify the extent to which O3 fumigation is causing a physiological stress response in the plants and to relate these events to changes in biochemical profiles.

Researcher(s)

• Promoter: Guisez Yves

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The research plan "Systems biology of organ growth" refers to the enormous importance of plant growth for society and economy (among others a source of renewable energy). The question is how it is possible that plants on the one hand can respond strongly and in a very predictable way to genetic variations and environmental conditions and on the other hand generate a morphology that is characteristic enough for each species that taxonomy can be based on it. The systems-biology approach will be worked out with a strong emphasis on the role of cell division and expansion. The research plan aims to enable a complete quantitative description of phenotypes caused by genetic or environmental perturbations and to transfer this knowledge into dynamic and mechanistic simulation models in which new hypotheses can be rigorously tested and to apply the obtained insight to improve the crop species maize.

Researcher(s)

• Promoter: Beemster Gerrit
• Fellow: Beemster Gerrit

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project website

Project type(s)

• Research Project

Abstract

The size and form of plants largely depend on the process of expansion that follows cell formation in the meristems. The project aims to study the elongation zone-specific genes of the Arabidopsis root, which were identified by micro-arrays performed on dissected elongation zones. A reverse genetics approach coupled to an in depth analysis of the genes will reveal their precise role in the elongation process.

Researcher(s)

• Promoter: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The aim of this project is to develop a simple, fast and accurate test for the diagnosis of T.b. gambiense sleeping sickness. The test should be very sensitive and is being developed on the basis of synthetic peptides.

Researcher(s)

• Promoter: Guisez Yves
• Fellow: Van Nieuwenhove Liesbeth

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The aim of this project is to evaluate three different kind of HSP as carriers for antigens and to test whether they are potent enough to induce a strong and efficient immune reaction within a mammalian model along with an increased CTL respons against the protozoan parasite T. parva. mHSP70 (a Mycobacterium derived HSP) will be used as a control, since most available data in the literature report on its use in fusion proteins. bHSP70 (from Bos taurus) will be used in order to ascertain the hypothesis whether specific host chaperones are beneficial in the induction of the CTL reaction. tHSP90 (derived from T. parva) is interesting to use because it was identified as one of the T. parva antigens which induces CTL (E. Taracha, personal communication). We will test in a quantitative way whether (or to what extend) the three fusion proteins are involved in 'cross presentation' next to the cytosolic MHC-I presentation, and are capable to make an immunological reaction stronger.

Researcher(s)

• Promoter: Guisez Yves
• Fellow: De Goeyse Ine

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Being sessile organisms, (higher) plants need to be able to quickly respond to a broad and diverse range of biotic and abiotic stimuli. Many signal transduction-pathways therefore continuously change the plant's development and metabolism in optimal accordance with the ever-changing environment. In many circumstances the direction and extent of growth is modified. To know how these different pathways modulate growth, we need to understand the growth process itself together with its control mechanisms.

Researcher(s)

• Promoter: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Verbelen Jean-Pierre
• Fellow: Van Loock Bram

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Plant growth and development have a direct impact on the balances and productivity of natural and agrarian ecosystems. The morphology of a plant, which can be influenced by biotic as well as by abiotic environmental factors, plays a determining role in plant growth and development. Chronical and ecologically relevant doses UV-B irradiation have an influence on the development and the morphology of the model organism Arabidopsis. The question concerning the underlying mechanism behind this phenomenon, is the central theme of this project.

Researcher(s)

• Promoter: Guisez Yves
• Co-promoter: Prinsen Els
• Fellow: Hectors Kathleen

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Being sessile organisms, (higher) plants need to be able to quickly respond to a broad and diverse range of biotic and abiotic stimuli. Many signal transduction-pathways therefore continuously change the plant's development and metabolism in optimal accordance with the ever-changing environment. In many circumstances the direction and extent of growth is modified. To know how these different pathways modulate growth, we need to understand the growth process itself together with its control mechanisms.

Researcher(s)

• Promoter: Verbelen Jean-Pierre
• Fellow: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Prinsen Els
• Fellow: Van Elst Daan

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Despite the essential role of vitamin C in the protection of plants and animals against threatening environmental conditions, important aspects of vitamin C metabolism remain unknown. This project aims at the characterization of a poorly characterized group of proteins that play a role in vitamin C maintenance and in oxidative stress defense responses.

Researcher(s)

• Promoter: Asard Han

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

In an era characterized by dramatic shrinking of fossil energy sources, plants, representing natural power stations, become more and more indispensable to support and maintain the well-being of our current human world population.Curiously enough, our present understanding of how plants develop and growth is still very limited and this shortage becomes exemplary when the subterranean part of the plant is considered. Roots however serve a multitude of functions that are essential for a normal growth and development of the plant. Within this network, 6 Belgian Laboratories assisted by an eminent European partner will combine efforts to tackle major aspects of root growth and development in a well-focused strategy by concentrating one species, Arabidopsis thaliana that turned out to be an ideal model system for root developmental research. The anticipated new insights will certainly become essential for all future approaches to enhance growth of plants as alternative energy sources.

Researcher(s)

• Promoter: Verbelen Jean-Pierre

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Hormonal interactions and action mechanisms controlling elongation growth in Arabidopsis.

Researcher(s)

• Promoter: Verbelen Jean-Pierre

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The long term goal of the research is the understanding of ascorbate metabolism in plants and animals. More specifically, this project investigates the physiological function and mechanism of action of cytochromes b551 (Cyts b561). These are widespread intrinsic membrane proteins, using ascorbate as an electron donor for trans-membrane electron transport (Okuyama et al. 1998). Cyts b561 play a yet unidentified role in ascorbate metabolism. Recent indications suggest that Cyts b561 may provide a link between iron and ascorbate metabolism, at least in mice (Mckie et at. 2001). The homology between mouse and Arabidopsis Cyts b561 is considerable, suggesting a similar function in plants. Arabidopsis is proposed as a model plant for these studies.

Researcher(s)

• Promoter: Asard Han

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

A lot of physiological processes are carried out by protein complexes. Complex formation between cyclin dependent kinases with varying regulatory cyclins is considered the major driving forces of the cell cycle. The formation and activity of such complexes is strongly regulated by different parameters such as the participating components, phosphorylation/dephosphorylation events, interaction with inhibitory (eg. KIP-related protein) and activating (CDK subunit protein) proteins. Complementary to genomical data, achieved by cDNA-AFLP and microarrays, a proteome technical analysis of these cell cycle related complexes is necessary that can give information about the dynamical changes of their activity and structure.The goal of this study is to optimise a bioanalytical method for the purification and isolation of protein complexes in order to study their dynamics during the cell cycle. This can reveal new complexes or constituents, active during a certain phase of the cell cycle. As model species, the highly synchronisable Nicotiana tabacum cv. Bright Yellow-2 (BY-2) or an Arabidopsis thaliana cell suspension culture is used. Samples from different phases are ground in liquid nitrogen or sonicated, and a fraction of a whole cell lysate is subjected to non-denaturing `Blue native polyacrylamide gelelectrophoresis (BN-PAGE)'(Schägger et al., 1991). In this first dimension, protein complexes are separated on the basis of their size. To exclude co-migration of several complexes, a second native dimension (ionexchange 'FPLC) will be incorporated. Samples are subsequently subjected to a denaturing second dimension, SDS-PAGE, in which the complexes will break up into their constituents. With this strategy, the dynamics of the complexes can by followed accurately during their progression through the cell cycle. Together with the TAP-technology group of dr. Geert De Jaeger, the cell cycle interactome will be studied and this can reveal new players during the cell cycle. Post-translational modifications like phosphorylation and glycosylation are important for the activity, stability and formation of protein complexes and will be studied.Identification of protein complexes with changes in abundancy or/and modifications is done by mass spectromectric analysis.

Researcher(s)

• Promoter: Prinsen Els
• Fellow: Remmerie Noor

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Horemans Nele

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Horemans Nele

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The root and hypocotyl of Arabidopsis serve as model systems to better understand the process of cell elongation. Using different micro-arrays, genes were identified that could play a major role in this process. Transgenic plants bearing promotor-GUS and -GFP constructs will be generated to study the expression pattern of these genes. Plants with altered levels of gene expression will serve to identify the phenotypic effects of these gene changes. All these experiments will shed more light on the precise role of the identified genes in the cell elongation process.

Researcher(s)

• Promoter: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Verbelen Jean-Pierre
• Fellow: Van Orden Jurgen

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The aim of this project is to develop a simple, fast and accurate test for the diagnosis of T.b. gambiense sleeping sickness. The test should be very sensitive and is being developed on the basis of synthetic peptides.

Researcher(s)

• Promoter: Guisez Yves
• Fellow: Van Nieuwenhove Liesbeth

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

`East coast fever' (ECF) is a tick-borne disease caused by the complex protozoan parasite Theileria parva. This parasite is related to Plasmodium spp. and causes an high mortality of cows in Eastern and Central Africa. The sporozoites of T. parva infect the B- and T-lymphocytes upon wich the host reacts with a cytotoxic T-cell (CTL) response. This cellular CD8+ immune reaction in ECF is very strong and probably determined by a limited amount of antigens, in contrast to the weak and complex immune reaction in case of Plasmodium. Most probably one of these antigens is situated in the polymorphic immunodominant molecule (PIM), a membrane protein that is coded by a single copy gene and that is abundantly present in the pathogenic schizont stadium. Vaccines composed of recombinant proteins are often weakly immunogenic and are therefore mostly administered together with so called adjuvants. Self-assembling particles that are coupled to specific antigens can enhance the supply of these antigens to antigen presenting cells and can also function as an adjuvant of the co-expressed proteins. Hepatitis B core antigen (HBcAg) is such kind of carrier and behaves as an immuno-stimulating molecule consisting of 180 subunits, each folding into a spike. After insertion of an antigen in such a spike, the immunological properties of the core are transferred to the insert. During the time course of this project recombinant hybrid particles of the HBcAg and the truncated PIM of T. parva will be applied as a vaccine injection for cows. The outcome of our experiments can be useful for the development of a safe immunization technique for ECF but will hopefully also contribute to the improvement of vaccination strategies in humans.

Researcher(s)

• Promoter: Guisez Yves
• Fellow: Janssens Michiel

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The aim of this project is to evaluate three different kind of HSP as carriers for antigens and to test whether they are potent enough to induce a strong and efficient immune reaction within a mammalian model along with an increased CTL respons against the protozoan parasite T. parva. mHSP70 (a Mycobacterium derived HSP) will be used as a control, since most available data in the literature report on its use in fusion proteins. bHSP70 (from Bos taurus) will be used in order to ascertain the hypothesis whether specific host chaperones are beneficial in the induction of the CTL reaction. tHSP90 (derived from T.parva) is interesting to use because it was identified as one of the T. parva antigens which induces CTL (E. Taracha, personal communication). We will test in a quantitative way whether (or to what extend) the three fusion proteins are involved in 'cross presentation' next to the cytosolic MHC-I presentation, and are capable to make an immunological reaction stronger.

Researcher(s)

• Promoter: Guisez Yves
• Fellow: De Goeyse Ine

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The aim of this project is to study if changes in the antioxidative metabolism play a role in cross-tolerance. It is our objective to look at stress responses of plants at different complementary levels including ecophysiological level, the accumulation of selected metabolites as well as at the expression level of selected genes.

Researcher(s)

• Promoter: Caubergs Roland
• Fellow: Horemans Nele

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Guisez Yves
• Co-promoter: Jansen Marcel
• Co-promoter: Prinsen Els
• Fellow: Hectors Kathleen

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project represents a research contract awarded by the University of Antwerp. The supervisor provides the Antwerp University research mentioned in the title of the project under the conditions stipulated by the university.

Researcher(s)

• Promoter: Guisez Yves
• Promoter: Van Onckelen Harry

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project studies the possible role of ascorbate (Vitamine C) as a stress sensor namely in the perception and transduction of abiotic stressresponses in plants. An integrated analysis of biochemical, genomical and proteomical changes will enable us to obtain information on the regulation of proteins involved in ascorbate metabolism at the plant plasma membrane during acute, sublethal cadmiumstress.

Researcher(s)

• Promoter: Horemans Nele

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Using a proteomics based phenotyping strategy the metabolic profiling of a fermentation reaction will be investigated. For this purpose Candida bombicola is used as a model for the fermentation of renewable vegetable oils and the production of sophorolipids. By optimizing the culture parameters the production will be correlated with the phenotype with the aim to select a strain suitable for industrial fermentation.

Researcher(s)

• Promoter: Witters Erwin

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Aim: Our research is devoted to the mechanisms that control cell elongation in seed plants and especially in roots. Given the role of roots in exploration of soil substrate, anchorage and uptake of nutrients, the expansion of root cells is necessary to develop a functional root system. The identification of certain actors in the process of cell elongation and its control is the aim of the present research proposal. It fits in the research themes of the lab that focus on different aspects of the cytoskeleton and the cell wall in relation to cell elongation (De Cnodder et aI., 2005; Kerstens en Verbelen, 2003; Le et aI., 2004; Verbelen et aI., 2005). Promotor and co-promotor have gained substantial experience in microscopy, root development and molecular biological techniques to supervise this research proposal.The body of higher plants consists of cells that are formed in meristems. Outside the meristems, these newly formed cells generally expand considerably before reaching a stage of differentiation and maturation. The development of the Arabidopsis thaliana root epidermis is well described at the meristem level, including the quiescent center and the founder cells that give rise to the epidermal cell files in the root (Benfey and Scheres, 2000; Dolan et aI., 1993; van den Berg et aI., 1998). The Arabidopsis root is useful for the study of cell elongation. It is small, exhibits a highly predictable developmental pattern and can be easily visualized (with a normal microscope). The cells that are formed in the meristem can be easily traced when they pass through the elongation zone to reach the differentiation zone. Fast elongation of these cells occurs in the zone 400-9001lm away from the root tip. In each trichoblast cell file of the epidermis a new cell enters the elongation zone every 30 min and elongates from 35 to 150llm in about 3 hours (Le et aI., 2001). Such a fast growth needs accurate control mechanisms of the cell's physiology. The cell wall needs to be loosened to permit the anisotropic growth, e.g. by the action of xyloglucan endotransglucosylase/hydrolases (XTHs, Vissenberg et aI., 2000, 2003, 2005a, 2005b) but at the same time, needs to remain strong enough to prevent lysis of the cell. Obiectives: We will identify regulatory genes that are activated at the start, the middle or the end of cell elongation depending on the transgenic line.

Researcher(s)

• Promoter: Verbelen Jean-Pierre
• Co-promoter: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

In this project plant cell cultures as well as whole Arabidopsis plants are chronically exposed to low Cd concentrations and the effect studied using physiological and biochemical techniques (e.g. measurements of ascorbate/dehydroascorbate, etc...). Also the effect on the development of whole plants from the seed are studied with physological and biochemical tools as well as the morphological impact. In another part the effect of Cd challenge on the changing proteome is studied.

Researcher(s)

• Promoter: Guisez Yves
• Co-promoter: Potters Geert

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The project's main objective is "To gain a fundamental insight in the cryo-physiology through a proteome study of banana meristems". It aims to contribute to a more fundamental knowledge of some of the physiological processes that underlie adaptation and acclimatization, as weIl as the mechanisms of stress injury. Many of these stress parameters are correlated. For example, water stress is often associated with salt stress in the root and/or heath stress in the leaves. Resistance towards freezing is highly dependent upon resistance towards tissue dehydration. Plants also often exhibit a cross- resistance what implies that the underlying mechanisms for resistance against different stress factors have common characteristics. These mechanisms are complex and their unraveling can only take place through long term and multidisciplinary research.

Researcher(s)

• Promoter: Prinsen Els
• Promoter: Van Onckelen Harry
• Co-promoter: Laukens Kris
• Co-promoter: Witters Erwin

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This research project combines the expertise and analytical infrastructure available in two different research laboratories. The main aim of the consortium is replacing the old GC-MS infrastructure by a new generation GC-MS/MS instrument, enabling further identification. This infrastructure will be used for developing new methods for the identification and analysis of stress-related components, with a potential use as markers for stress. At the scientific level, the research domains are strictly separated ((1) stress response in plants and (2) oxidative stress in chronical diseases), however, the stress response and the methodology are in common.

Researcher(s)

• Promoter: Prinsen Els
• Co-promoter: Manuel Y Keenoy Begona

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

In this project we want to set up a model system for both physiological and molecular purposes and use Physcomitrella for a functional genetic analysis of the regulation of the physiology of cell division and elangation by ASC and GSH.

Researcher(s)

• Promoter: Caubergs Roland
• Co-promoter: Horemans Nele
• Co-promoter: Potters Geert

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project aims the study of the effects of a range of abiotic factors (level of mineral nutrition and water) as well as inoculation of plants with cytokinin producing microorganisms on dynamics of cytokinin content and metabolism in plants. We plan to test a hypothesis that (1) long-term effect of unfavorable environment leads to a deficit in cytokinins limiting growth of plants when they return to optimal conditions and that (2) inoculation of plants, which have experienced detrimental effect of the environment, with cytokinin producing microorganisms might compensate this deficit of cytokinins and in this way to accelerate growth and increase productivity of plants.

Researcher(s)

• Promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Guisez Yves
• Fellow: Horvath Joeri

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Guisez Yves
• Fellow: Van Nieuwenhove Liesbeth

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Guisez Yves
• Fellow: De Goeyse Ine

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

From a huge collection of enhancer-trap plants with GFP expression under a plant-own promoter/enhancer, only these plants with expression in the root elongation zone will be studied. The trapped genes will be identified using TAIL-PCR, knock-out plants will be phenotypically characterized and the gene products will be localized. This research will identify genes/proteins that initiate and terminate cell elongation.

Researcher(s)

• Promoter: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Vitamin C (ascorbate) plays an essential role in numerous physiological processes in animals and plants. In this project, role of a newly described class of ubiquitous membrane proteins, cytochromes b561, in ascorbate and iron metabolism is investigated. Arabidopsis thaliana is used as a model organism. Results will contribute to our understanding of iron and ascorbate metabolism in plants and mammals.

Researcher(s)

• Promoter: Asard Han

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Microorganisms present in the rhizosphere secrete phytohormones. Although plants synthesize their own phytohormones, also phytohormones present in the rhizosphere penetrate into the plant. In this research project, we will analyze a Bacillus subtilis strain, characterized to be a high cytokinin producer. This rhizosphere bacterium induces growth and development of the plant as well as increases the plant's resistance toward drought, heavy metals and infection diseases.

Researcher(s)

• Promoter: Prinsen Els
• Fellow: Arkhipova Tatyana

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Prinsen Els
• Promoter: Van Onckelen Harry
• Promoter: Vissenberg Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Caubergs Roland
• Promoter: Guisez Yves

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

In the present study, we propose a detailed analysis of the function of the Arabido~is PPR-Iike 1 protein. Our preliminary data indicate that this protein might operate as an integrator of multiple pathways. The PPR-Iike1 gene encodes a pentatricopeptide repeat (PPR) protein. The PPR motif has recently been described and found to be occurring in one of the largest Arabido~is gene families (Small and Peeters, 2000). So far, very little is known about the function of this motif, but it is clearly related to the widespread TPR (tetratricopeptide repeat) protein-binding motif. The latter is present in the SPY protein, a negative regulator of gibberellin action in Arabido~is, and has recently been shown to participate in protein-protein interactions essential for the proper functioning of SPY (Tseng etal. , 2001; Izhaki et al. , 2001 ). Like TPR, the PPR motif is predicted to consist of two a-helices and thereby may have protein-binding propel1ies. To date, several PPR-containing genes have been cloned, and all these PPR proteins were found to be targeted into either the mitochondria or the chloroplasts. Their function appears rather diverse. For instance, Arabidopsis HCF152 is involved In processing of chloroplast psbB-psbT -psbH-petB-petD RNAs as a homodimer with RNA- binding properties (Meierhoff et al., 2003; Nakamura et al., 2003). Likewise, maize CRP1, is involved in chloroplast petD RNA processing and petD and petA translation (Fisk et al., 1999). Petunia Rf is mitochondrially targeted and capable of restoring fertility to cytoplasmic male-sterile plants (Bentolila et al., 2002). Two radish male fertility restorer genes Orf687 and Rfo also encode PPR proteins (Koizuka et al., 2003; Brown et al., 2003). Because of the prevalence of the huge number of different PPR genes in Arabidopsis genome, one can hypothesize that the functions of these PPR proteins could be rather divergent.

Researcher(s)

• Promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project envisages identifying components of the signal transduction cascades during oxidative stress in plants by means of an integrated immunological and proteomic approach. During its development a plant is continuously exposed to various kinds of stress. Its ability to react to these changes in a fast and appropriate manner is essential for its survival. Very often, changes in hormone homeostasis play an important role. Our knowledge regarding the role of plant growth regulators such abscisic acid (ABA), ethylene, jasmonic acid (JA) and salicylic acid (SA) as important signal molecules in stress responses is already substantial. Stress induced auxin and cytokinin action has been described in a restricted set of stress phenomena. Various studies point to oxidative stress as a central component in many cellular responses (Desikan et al., 2001; Neill et al., 2002). Oxidative stress results from an imbalance in the production and metabolism of reactive oxygen species (ROS). ROS are produced as a response to exposure to biotic and abiotic stress and act as a signal that triggers a variety of molecular, biochemical and physiological events. Nitrogen monoxide (NO) is very often an important component in the underlying signal transduction cascades. NO, a gaseous free radical, can interact with ROS in a number of ways and as such influences the response to biotic and abiotic stress factors (Delledonne et al., 1998; Neill et al., 2002; Neill et al., 2003). As is the case in animal models, cyclic GMP and cyclic ADPR are put forward as signal molecules in the plant NO signal transduction system. Cyclic GMP is produced in plants as a response to NO application (Pfeiffer et al., 1994) and in turn cADPR synthesis is thought to be induced by cGMP. Both have been shown to mimic certain functions of NO (Durner et al., 1998), and a specific inhibitor of guanylyl cyclase (ODQ) inhibits Arabidopsis thaliana NO-induced cell death. A membrane permeable cGMP-analog, 8-Br-cGMP, eliminates this inhibitory effect (Clarke et al., 2000). In animal systems, stress induced cADPR synthesis is activated via cGMP-dependent protein kinase. Until now, the existence of such a protein in higher plants has not been reported yet. The recent isolation of the gene for a putative cyclic nucleotide dependent protein kinase in our lab is a convincing candidate for this function. In its promoter region a considerable number of stress-regulated elements are found, such as the ABA-response element (ABRE), the "heat shock"-response element, the ABRE related "GC-repeat" (Litis et al., 1992) and the cold and water stress regulated dehydration (DRE)/"C-repeat"-response elements (Baker et al., 1994). The additional presence of a salicylic acid regulated promoter element (TCA), a wound induced response element, (WUN) (Pastuglia et al., 1997), and of the "TC-rich repeat", a stress and defence induced response element (Klotz en Lagrimini 1996), strengthens our proposition for a stress related function of this putative cyclic nucleotide dependent protein kinase.

Researcher(s)

• Promoter: Prinsen Els
• Promoter: Van Onckelen Harry
• Co-promoter: Laukens Kris
• Co-promoter: Roef Luc
• Co-promoter: Witters Erwin

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project fits within the context of the proteome-analytical study of the regulation of the plant cell-cycle, using the tobacco BY-2 cell cuspension culture. This research continuously yields large and complex data-sets, of which the processing, integration and analysis are a major challenge. The project aims at bringing together all databases and tools on a central bioinformatics platform in order to achieve efficient data-handling. The new platform consists of a computer-cluster with sufficient processing power and storage capacity, on which a range of bioinformatics tools will be installed. The platform enables a number of new applications: construction of relational proteome databases, clustering of proteins based on parameters such as observerd expression levels, in silico proteolytic cleavage of complete databases to aid the interpretation of experimental data, etcetera. Although the analysis of tobacco BY-2 proteome data is the primary focus of this project, the platform will be valuable to other projects as well.

Researcher(s)

• Promoter: Laukens Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

A lot of physiological processes are carried out by protein complexes. Complex formation between cyclin dependent kinases with varying regulatory cyclins is considered the major driving forces of the cell cycle. The formation and activity of such complexes is strongly regulated by different parameters such as the participating components, phosphorylation/dephosphorylation events, interaction with inhibitory (eg. KIP-related protein) and activating (CDK subunit protein) proteins. Complementary to genomical data, achieved by cDNA-AFLP and microarrays, a proteome technical analysis of these cell cycle related complexes is necessary that can give information about the dynamical changes of their activity and structure.The goal of this study is to optimise a bioanalytical method for the purification and isolation of protein complexes in order to study their dynamics during the cell cycle. This can reveal new complexes or constituents, active during a certain phase of the cell cycle. As model species, the highly synchronisable Nicotiana tabacum cv. Bright Yellow-2 (BY-2) or an Arabidopsis thaliana cell suspension culture is used. Samples from different phases are ground in liquid nitrogen or sonicated, and a fraction of a whole cell lysate is subjected to non-denaturing `Blue native polyacrylamide gelelectrophoresis (BN-PAGE)'(Schägger et al., 1991). In this first dimension, protein complexes are separated on the basis of their size. To exclude co-migration of several complexes, a second native dimension (ionexchange 'FPLC) will be incorporated. Samples are subsequently subjected to a denaturing second dimension, SDS-PAGE, in which the complexes will break up into their constituents. With this strategy, the dynamics of the complexes can by followed accurately during their progression through the cell cycle. Together with the TAP-technology group of dr. Geert De Jaeger, the cell cycle interactome will be studied and this can reveal new players during the cell cycle. Post-translational modifications like phosphorylation and glycosylation are important for the activity, stability and formation of protein complexes and will be studied.Identification of protein complexes with changes in abundancy or/and modifications is done by mass spectromectric analysis.

Researcher(s)

• Promoter: Prinsen Els
• Promoter: Van Onckelen Harry
• Co-promoter: Witters Erwin
• Fellow: Remmerie Noor

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Caubergs Roland

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Guisez Yves
• Fellow: Rogé Stijn

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Prinsen Els
• Promoter: Van Onckelen Harry
• Fellow: Swiatek Agnieszka

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Since the use of the chemical growth regulator CCC has been omitted for pear, the optimal balance between vegetative and generative growth of pear trees is impaired. Fruitsetting is the best controller of vegetative growth. Therefore, there is a trend to control fruitsetting via Gibberellin treatment. A new growth retardant, Prohexadione-Calcium, a blocker of the GA biosynthesis, has been developed. Systematic treatment by this GA blocker of exogenous GA's blindly interferes with the natural hormone homeostasis of the trees. This might induce severe risks in the predictability of flower bud induction. This project aims the analysis of (1) fruitsetting, (2) the molecular-physiological background and (3) the phytohormone balance after treatment with GA3, GA4/7 and Prohexadione Calcium on 4-year old Conference pear trees.

Researcher(s)

• Promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

`East coast fever' (ECF) is a tick-borne disease caused by the complex protozoan parasite Theileria parva. This parasite is related to Plasmodium spp. and causes an high mortality of cows in Eastern and Central Africa. The sporozoites of T. parva infect the B- and T-lymphocytes upon wich the host reacts with a cytotoxic T-cell (CTL) response. This cellular CD8+ immune reaction in ECF is very strong and probably determined by a limited amount of antigens, in contrast to the weak and complex immune reaction in case of Plasmodium. Most probably one of these antigens is situated in the polymorphic immunodominant molecule (PIM), a membrane protein that is coded by a single copy gene and that is abundantly present in the pathogenic schizont stadium. Vaccines composed of recombinant proteins are often weakly immunogenic and are therefore mostly administered together with so called adjuvants. Self-assembling particles that are coupled to specific antigens can enhance the supply of these antigens to antigen presenting cells and can also function as an adjuvant of the co-expressed proteins. Hepatitis B core antigen (HBcAg) is such kind of carrier and behaves as an immuno-stimulating molecule consisting of 180 subunits, each folding into a spike. After insertion of an antigen in such a spike, the immunological properties of the core are transferred to the insert. During the time course of this project recombinant hybrid particles of the HBcAg and the truncated PIM of T. parva will be applied as a vaccine injection for cows. The outcome of our experiments can be useful for the development of a safe immunization technique for ECF but will hopefully also contribute to the improvement of vaccination strategies in humans.

Researcher(s)

• Promoter: Guisez Yves
• Fellow: Janssens Michiel

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

A lot of physiological processes are carried out by protein complexes. Complex formation between cyclin dependent kinases with varying regulatory cyclins is considered the major driving forces of the cell cycle. The formation and activity of such complexes is strongly regulated by different parameters such as the participating components, phosphorylation/dephosphorylation events, interaction with inhibitory (eg. KIP-related protein) and activating (CDK subunit protein) proteins. Complementary to genomical data, achieved by cDNA-AFLP and microarrays, a proteome technical analysis of these cell cycle related complexes is necessary that can give information about the dynamical changes of their activity and structure.The goal of this study is to optimise a bioanalytical method for the purification and isolation of protein complexes in order to study their dynamics during the cell cycle. This can reveal new complexes or constituents, active during a certain phase of the cell cycle. As model species, the highly synchronisable Nicotiana tabacum cv. Bright Yellow-2 (BY-2) or an Arabidopsis thaliana cell suspension culture is used. Samples from different phases are ground in liquid nitrogen or sonicated, and a fraction of a whole cell lysate is subjected to non-denaturing `Blue native polyacrylamide gelelectrophoresis (BN-PAGE)'(Schägger et al., 1991). In this first dimension, protein complexes are separated on the basis of their size. To exclude co-migration of several complexes, a second native dimension (ionexchange 'FPLC) will be incorporated. Samples are subsequently subjected to a denaturing second dimension, SDS-PAGE, in which the complexes will break up into their constituents. With this strategy, the dynamics of the complexes can by followed accurately during their progression through the cell cycle. Together with the TAP-technology group of dr. Geert De Jaeger, the cell cycle interactome will be studied and this can reveal new players during the cell cycle. Post-translational modifications like phosphorylation and glycosylation are important for the activity, stability and formation of protein complexes and will be studied.Identification of protein complexes with changes in abundancy or/and modifications is done by mass spectromectric analysis.

Researcher(s)

• Promoter: Van Onckelen Harry
• Co-promoter: Witters Erwin
• Fellow: Remmerie Noor

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Caubergs Roland

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Caubergs Roland

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Van Onckelen Harry
• Fellow: Remmerie Noor

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Using a proteomics based phenotyping strategy the metabolic profiling of a fermentation reaction will be investigated. For this purpose Candida bombicola is used as a model for the fermentation of renewable vegetable oils and the production of sophorolipids. By optimizing the culture parameters the production will be correlated with the phenotype with the aim to select a strain suitable for industrial fermentation.

Researcher(s)

• Promoter: Van Onckelen Harry

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Several clues exist for the involvement of the NO-cGMP-cADPR transduction pathway in responses to stress conditions in plants. This transduction pathway is possibly analogous to the one already known in animals. A proper characterisation of the mechanism by which the cyclic GMP signal activates a cyclic ADPR signal is currently missing for plants. For several years now, the laboratory for plant biochemistry and physiology of the university of Antwerpen has been researching cyclic nucleotides in plants. During the course of this research it was shown that Nicotiana tabacum 'BY-2' cells and Arabidopsis thaliana express a putative cyclic nucleotide dependent protein kinase/phosphatase gene. Based on sequence homology we expect the encoded protein to contain a domain resembling protein phosphatase 2C, followed by a cyclic nucleotide binding domain and a catalytical kinase domain (=> PP2C-PKNR-PKNC). This is a surprising digression from the prototypical cyclic nucleotide dependent protein kinases as they are known in yeasts or animals. Several alternative transcripts appear and preliminary data seem to indicate a fluctuation during the cell cycle. An analysis of the putative promoter regions of this gene showed several response elements regulated not only by the cell cycle, but by light and stress as well. The aim of this project is to determine the relation of this protein to the elements of the proposed NO-cGMP-cADRP transduction pathway, based on the previously described observations. To achieve this we plan to use plants (Arabidopsis en BY-2) available to us in the lab, in which (several variant forms) of the protein are either over-expressed or knocked-out. Plants (Arabidopsis en BY-2) containing promoter-EGFP-GUS constructs will be used as well. These organisms, both wild-type and transformant, will be subjected to different kinds of biotic and abiotic stress and the different signalling molecules (NO, cGMP, cADPR) will be individually administered to them. Each time the signalling molecules will be observed using biochemical, microscopical and proteomics techniques. Observation of differences in these molecules and morphological differences between wild-type and mutant plants, with the knocked-out or the constitutively activated gene, should provide us with indications about the functioning of the gene in the proposed transduction pathway.

Researcher(s)

• Promoter: Van Onckelen Harry
• Co-promoter: Roef Luc
• Fellow: Van Ingelgem Carl

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Each plant starts from a minimal embryo. Plant growth is the result of a defined process where each tissue generates new cells, which on their turn expand and differentiate. This research community will focus on the role of phytohormones on cell division, cell expansion, root development, flower induction, apical dominance, dormancy, UV tolerance and photosynthesis. The research community groups 14 research units from 12 different universities/research institutes.

Researcher(s)

• Promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

An essential characteristic of plants is their ability to respond to stress conditions. Plants raised under solar radiation are acclimated to ambient UV-B levels, a response that prevents damaging UV-driven reactions. The aim of this project is to test the hypothesis that the expression levels of a small number of peroxidase isozymes control both UV-protection and, via effects on auxin homeostasis, UV-B induced morphogenesis. We will identify UV-regulated peroxidase isozymes using proteomic analysis, and study UV-protection and phytohormone metabolism in Arabidopsis thaliana overexpressing these isozymes.

Researcher(s)

• Promoter: Guisez Yves

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Bacterial leaf nodulation is a model of exceptional collaboration of bacteria and higher plants. The presence of the endosymbiont is absolutely required to ascertain survival of the host. Several possible factors might be involved in leaf nodulation, including nitrogen fixation and production of plant growth promoting substances by the bacteria. By looking for the presence of bacterial genes encoding nitrogen fixation and/or hormone synthesis, we will provide this research with a genetic basis to evaluate the extend to which these two organisms mutually interact.

Researcher(s)

• Promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Horemans Nele

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

This project aims to elucidate the molecular mechanisms, by which cyclic nucleotides and cytokinins regulate the higher plant cell cycle. Earlier research yielded some interesting binding proteins, among which cAMP-binding Nucleoside Diphosphate Kinases and a cytokinin-binding Adenosine Kinase. By using Nicotiana tabacum BY-2 (Bright Yellow-2) cell suspension cultures as well as Arabidopsis thaliana whole plants and cell cultures, the interactions of cyclic nucleotides and cytokinins with the plant proteome are further investigated. This study consists of three major parts. The first part focusses on searching and identifying proteins that are affected by cyclic nucleotides or cytokinins. Either affinity chromatography and photo-affinity labeling techniques are used to find proteins that interact directly with these signalling molecules. By means of two-dimensional electrophoresis and specific detection techniques, proteins undergoing post-translational modifications, affected by cAMP or cytokinins, are revealed. Differential proteome analysis can show which gene products are up- or downregulated by these regulators. Potentially interesting proteins are systematically identified with several mass spectrometrical techniques. The second part of this study consists of cloning the relevant genes, by means of a PCR strategy. Transcript levels of these individual genes are studied. Recombinant GFP-fusion constructs are expressed in suspension cells as well as in whole plants, to investigate the spatio-temporal distribution of the gene products. In the third part of the project, gene products that show potential cAMP or cytokinin regulated functions, will be thoroughly characterised. The proteins are therefore produced in an expression system. Interacting partners are searched by means of affinity chromatography and biosensor techniques, and subsequently identified. All identity data arising from this project will be continuously implemented in the tobacco BY-2 proteome database, which has already been published online. Besides identity data, information regarding relevant interactions with other components, post-translational modifications and expression information are added. The combination of these approaches will provide a comprehensive picture of the signal transduction chain of cAMP and cytokinins in relation to the plant cell cycle.

Researcher(s)

• Promoter: Van Onckelen Harry
• Fellow: Laukens Kris

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The project aims at establishing the biochemical properties and physiological role of a number of splice variants of a totally new putative hybrid cyclic nucleotide dependent protein kninase/phosphatase from higher plants by means of a combination of state of the art methods in genetic analysis and proteome analysis. A focus is put on a presumed role in the regulation of the plant cell cycle.

Researcher(s)

• Promoter: Roef Luc

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Caubergs Roland

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Guisez Yves

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Van der Auweraert Ann

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Caubergs Roland
• Co-promoter: Guisez Yves
• Fellow: Pasternak Taras

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Prinsen Els
• Promoter: Van Onckelen Harry

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Preliminary data from a genetic analysis point at an increased photorespiratory activity in tomato plants treated with a low dosage of cadmium. To confirm of contradict th is hypothesis, we will study photosynthesis, phÇ)torespiration, anti-xenobiotic defences (glutathione and phytochelatins) in intact plants, or through a combination of biochemical and molecular techniques, in function of cadmium stress.

Researcher(s)

• Promoter: Caubergs Roland
• Co-promoter: Potters Geert

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The importance of class 111 peroxidases in the UV -b protection respons of plants bas recently been discovered. However, it bas become clear that only specific peroxidase isozymes contribute to the protection respons. To understand the molecular basis ofthis specificity, it is essential to isolate and characterise (proteomics) the UV induced peroxidase(s). We will study expression and regulation of the UV -induced peroxidases in transgenic Arabidopsis thaliana.

Researcher(s)

• Promoter: Guisez Yves
• Co-promoter: Jansen Marcel

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Caubergs Roland

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Caubergs Roland

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Caubergs Roland

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Abscisic acid is a phytohormone that, besides ethylene and jasmonate, plays an important role in the interaction between plants and pathogenic micro-organisms. Research at the RUG has shown that ABA mutants of tomato are much more resistant to Botridis cinerea and Sclerotinia sclerotiorum than WT plants, but they do not show a changed susceptibility to the biotrophic pathogen Oidium lycopersici. The hypothesis that we want to test in this project is that certain broad spectrum pathogens interfere with a decrease in ABA after infection by producing ABA or stimulating ABA production by the host (or suppress ABA breakdown by the host). Because of this, defence reactions of the plant are suppressed. This could explain why interactions with these pathogens are generally compatible. We want also to study whether broad spectrum AM use similar mechanisms to suppress plant defense.

Researcher(s)

• Promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Auxins, specifically indole-3-acetic Acid (IAA), are synthesized by plants, fungi and bacteria. The physiological role as well as the signal transduction cascade in plants has been studies intensively yet. However, auxin biosynthesis is poorly understood. This project aims to understand the IAA biosynthesis by Azospirillum brasilense. The experimental plan has 3 levels: (1) Regulation of ipdC expression, (2) biochemical analsis of purified IPyA-decarboxylase and (3) Quantitative analysis of IAA- metabolites and mRNA's, corresponding with IPyP-decarboxylase and regulatory proteins involved in ipdC gene expression, of cells grown under strictly controlled conditions.

Researcher(s)

• Promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Guisez Yves

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Guisez Yves
• Co-promoter: Horemans Nele

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Van der Auweraert Ann

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Caubergs Roland
• Fellow: D'Haese David

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

In the present proposal, different emerging technologies will be applied and integrated to create innovative, sensitive and discriminating technologies for environmental toxicity assessments: DNA array technology and bio-informatics. The global objective of the present proposal is to develop an expert system linked to a bio-informatics platform that can distinguish the mode of action of chemicals based on the gene expression profile it induces within in vitro cell systems. This model will be developed in two steps: we will first start to evaluate the potential to classify the toxic effects of a group of highly (structurally) diverse environmental contaminants representing the major toxicological modes of action. Using the gene expression profiles, measured using micro-arrays, we will construct a bio-informatics classifier as an expert model. This model will then be assessed on its robustness (how does the system recognize known molecules?), its correctness (how are chemicals with the same mode of action classified?) and its discriminatory power (how good can theoretically distinct modes of actions be recognised?) Once the initial version of the model works we will, in a second tiered step, further refine the classifier by studying chemicals with a defined mode of action: endocrine disrupting chemicals. Testing these highly similar working chemicals displaying more structural similarity on the in vitro system will be the ultimate challenge to explore the full potential of this promising technology.

Researcher(s)

• Promoter: Van Onckelen Harry

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Van Onckelen Harry
• Fellow: Witters Erwin

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Caubergs Roland
• Fellow: Potters Geert

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Guisez Yves

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Guisez Yves
• Co-promoter: Horemans Nele

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The objective of the IUAP proposal "Growth and development of higher plants" is to understand how plant roots develop and interact with the environment. To this end 14 research groups from 6 universities and 1 research institute will join forces and integrate their respective expertises in genomics, proteomics, map-based cloning of mutants, morphology, hormone analysis, physiology and bio-informatics.

Researcher(s)

• Promoter: Van Onckelen Harry
• Co-promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The project aims at elucidating a number of signal transduction processes involved in cell cycle and programmed cell death in higher plants through implementation and integration of the state of the art expertice in genomics (RUG) and a highly performant infrastructure for proteomics at the recently inaugurated centre for mass spectrometry (CEMOVA) at the University of Antwerp. Specifically the signal transduction chains for cytokinins, cyclic nucleotides and jasmonic acid will be put under scrutiny.

Researcher(s)

• Promoter: Van Onckelen Harry

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Asard Han
• Co-promoter: De Coen Wim
• Co-promoter: Saluja Jyoti

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The project aims to analyse the variety of metabolic proteins and binding proteins involved in the cytokinin and cyclic nucleotide metabolism using proteomics. The strategies are based on an analytical sequence of high resolution protein separation, applied bioinformatics in protein analysis and mass spectrometric identification, and will be tested in two physiological models of Nicotiana tabacum.

Researcher(s)

• Promoter: Witters Erwin

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Tocotrienols constitute a novel and powerful antioxidant with a broad range of application. These molecules are structurally related to tocopherols (vitamin E) and are involved in the scavenging of reactive oxygen molecules that are damaging to the cell. The tocotrienol biosynthesis in higher plants will be studied, with particular attention to the enzymes involved and their subcellular localisation.

Researcher(s)

• Promoter: Caubergs Roland
• Fellow: Horvath Joeri

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Horemans Nele

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

About the role of plant hormones in nodulation no direct data are available but it seems plausible that auxins and especially cytokinins are involved in the nodulation proces. It is not known whether this occurs via altered hormone balances or via altered hormone susceptibilities. Moreover, it can not be excluded that bacterial production of plant hormones could contribute to certain aspects of nodule development. The aim of the present project on the Azorhizobium caulinodans-Sesbania rostrata symbiosis is to answer the following questions : (i) Nod-factor producing bacteria do they induce a local redistribution in the endogenous auxin-cytokinin balance and (ii) how does bacterial phytohormone synthesis contributes in nodule development?

Researcher(s)

• Promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Clubroot is a gal!-forming pathogen of brassicas which can have devastating effects on crop yield. The aim of this project is to measure the changes in the amounts and ratios of the diffe.rent forms of plant hormones during clubroot infection and subsequent gal! formation. This information is critica' to an understanding of (a) how alterations in plant hormones lead to gal! formation in the susceptible cultivar and (b) to the basis of tolerance to clubroot.

Researcher(s)

• Promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Using synchronized tobacco cell suspension cultures a causal relation between a required and transient cytokinin peak and the mitotic maximum was observed. Likewise, a required and transient cyclic nucleotide peak during the GIS-phase ofthe cell cycle was detected. This research topic aims to identify the metabolic proteins and the binding protein and or receptor complex switched on at a specific stage of the cell cycle by either one ofthe analytes or its precursors. Using affinity chromatography and or 2D gel electrophoresis protein mixtures will be purified and separated. By means of optical spot-analysis of the 2D gels phase specific 'candidate' proteins can be isolated for further identification. Mass spectrometric identification of those proteins will be made possible either by using protein-fingerprinting and or sequence tag database mining or by de novo sequence analysis.

Researcher(s)

• Promoter: Witters Erwin

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Van Onckelen Harry

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

The aim of this project is the analysis of primary action of light during photomorfogenesis and kinetic study of the endogenous content and metabolism of cAMP and phytohormones in higher plants (Phaseolus vulgaris) and Crown gall tissue (tobacco and Helianthus).

Researcher(s)

• Promoter: Van Onckelen Harry
• Fellow: Van Onckelen Harry

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Ascorbate (vitamin C) plays an essential role in the scavenging of reactive oxygen species. This function is being investigated in plant cells. Special attention is given to aspects of ascorbate transport at the plant plasma membrane, the effect of ascorbate on growth of cell cultures and its involvement against various stress factors (e.g. heavy metals, biotic stress factors).

Researcher(s)

• Promoter: Caubergs Roland
• Fellow: Horemans Nele

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Plasma membranes of higher plants contain specific electron transporting redox components, including a specific b-type cytochrome. The physiological function of these components is being investigated by altering their expression levels in Arabidopsis and by investigating their specific distribution in different tissues. The cytochrome will be purified and its primary structure will be analyzed.

Researcher(s)

• Promoter: Asard Han
• Co-promoter: Guisez Yves
• Fellow: Asard Han

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

A panoplia of microorganisms are associated with higher plants. The interactions can be very diverse going from associated to intimate and from benificial to pathogenic. In this Research Community, Plant-microbe interactions are studied multidisciplinary : (i) ecological aspects, (ii) molecular mechanisms of the mode of recognition, (iii) changes in behaviour en/or gene expression of both partners. This research community is the follow up of a research community called 'Molecular aspects of Plant-Microbe Interactions' directed by prof. Dr. J. Vanderleyden (KUL).

Researcher(s)

• Promoter: Prinsen Els

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

Plant growth regulators play a crucial role in controlling growth and development of higher plants. It is the aim of this research community to study the specific function and interactions of these hormones. In order to approach this subject from several angles a broad scoop of expertise was brought together in this research community.

Researcher(s)

• Promoter: Van Onckelen Harry

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project