Council members
Members of the PhD Student Council of EPS
Jennifer de Jonge (CHAIRWOMAN), also member of the Wageningen PhD CouncilPhD, BU Bioscience, Plant Research International, Wageningen University and Research Centre
About my Research
Description: Loss of meristematic activity in the embryonic or plantlet stage can occur with several vegetable crops, including tomato, pepper, broccoli and kohlrabi. This phenomenon can cause a severe loss of production and reduction of quality of the plantlets. This loss of meristematic activity has both a genetic and an environmental origin.
Research objectives: The project aims to understand the genetic and physiological factors that influence the response of the shoot apical meristem (SAM) to environmental conditions. This acquired knowledge will support seed companies to breed for varieties that are adapted to growth under low energy input conditions, including varieties that are less susceptible to shoot apical meristem determination (blindness, budless or shoot-less).
The project will also enable seed companies to improve their seed treatment protocols for varieties susceptible for blindness and will provide nurseries with information regarding critical environmental factors which induce shoot apical meristem determination during transplant production. Brassica and tomato are chosen as model species because they allow a combination of physiological and genetic approaches and the fact that with both crop species considerable economic losses occur as the result of the appearance of blind plants.
Most Dutch seed companies and plant raisers are actively involved in the project.
Cindy ten BroekePhD, Entomology, Wageningen University and Research Centre
About my research
Problem: The black current-lettuce aphid, Nasonovia ribisnigri, is an economically important pest of lettuce. The control of the lettuce aphid in cultivated lettuce is largely based on genetic host plant resistance, considered to be the most desirable control measure for this aphid. Host plant resistance is based on a single gene, the Nr-gene, which provides absolute resistance against N. ribisnigri in lettuce. Despite its importance in controlling N. ribisnigri, the resistance mechanism is not known.
Principles: The penetration behavior of N. ribisnigri and the location of the mechanism causing resistance inside the lettuce will be studied using the electrical penetration graph technique (EPG). Bioassays will be performed to further study the behavior of the aphids. In order to validate any causal effects of differentially expressed proteins or metabolites, an artificial feeding assay will be developed, by which the effects of putative resistance factors on aphid behavior and performance will be quantified.
Goal: To unravel the resistance mechanism of the Nr-gene in lettuce by behavioral and performance studies of the aphid.
Wilma van EssePhD, Biochemistry, Wageningen University and Research Centre
About my research
Modelling receptor recruitment into different signalling pathways
The Brassinosteroid Insensitive 1 (BRI1)-associated receptor Kinase 1 (BAK1) also referred to as SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE 3 (SERK3), is a co-receptor of the main plant steroid hormone (brassinolide) perceiving receptor BRI1. Interestingly, next to its involvement in plant development, BAK1/SERK3 is also an important component of the innate immunity system (e.g., PAMP signaling) acting as a co-receptor of the flagellin perceiving receptor FLS2. These two pathways, development and defense function independently yet use the same co-receptor. It is unknown how BAK1 is divided over different signals pathways that employ BAK1. In my project the overall aim is to establish a mathematical model for BAK1 distribution over the different signaling pathways. The first question that will be addressed is how many BAK1 receptors are used in Brassinosteroid signaling pathway. To achieve this goal several disciplines ranging from quantitative fluorescence microscopy and biochemistry are applied in a systems biology type of approach.
Tila Romina MenzelPhD, Entomology, Wageningen University
About my Research
As sessile organisms, plants are under the constant threat of suffering a fatal attack by herbivorous arthropods and all kinds of pathogens. Hence, plants possess different defense mechanisms that serve to protect them from these attackers. In general, a distinction is made between direct and indirect protective mechanisms. Direct defenses immediately interfere with the attacker and are often delivered as toxins and deterrents, but can also be composed of morphological features such as thorns and trichomes. In contrast, indirect defenses exploit the action of higher trophic levels, i.e. predators and/or parasitoids of the attacker, which are summoned by the plants via release of herbivore-induced plant volatiles (HIPV). In my project I will use Lima bean plants to study the effects of a preceding attack or application of phytohormones on subsequent attacks by herbivorous insects in terms of indirect defense. Moreover, I aim to investigate how this manifests itself in the plants and how the plant response differs when initiated by different types of herbivores.
Pierre-Yves ChibonPhD, Plant Breeding, Wageningen University
Pádraic FloodPhD, Laboratory of Genetics and Horticultural Production Chains, Wageningen University and Research Centre
About my Research
Natural Genetic Variation in Plant Photosynthesis
My Interest: Photosynthesis and genetics are essential, together providing the energy and the data with which life can be built, without either, life as we know it would not exist. Statements like this have been said so often that they have become clichéd, but this does not lessen their veracity and should not lessen their impact. For me cliché or not both photosynthesis and genetics are fascinatingly complex and fundamental, their complexity means there is lots to discover and their fundamentality gives such discoveries meaning.
My Research: My project bridges both of these topics, I am interested in natural genetic variation in plant photosynthesis and am using Arabidopsis thaliana as my model for this investigation. I work with a population of 350 Arabidopsis genotypes which were collected from all over the world, and as such represent a considerable portion of the diversity present in this species. I hope to screen this population for genetic diversity in photosynthesis and use this information to perform a genome wide association mapping study in order to find QTLs. Once such QTLs have been identified I hope to do more detailed genetic analysis in order to find the underlying genes or transcription factors which give rise to the variation in photosynthesis present in this population.
My Aim: The ultimate aim of my project is to find genes and describe genetic networks associated with photosynthesis. In addition to this main aim I hope that an understanding of the genetics of photosynthetic variation in the model organism Arabidopsis can also be used to improve crops and aid ecophysiological investigations into variation in photosynthesis in natural systems.
Juliane TeapalPhD, Laboratory of Plant Cell Biology, Wageningen University and Research Centre
About my Reseach
Microtubules (MTs) are connected to one another to form elaborate networks in living cells. The polarity of MTs within networks is exploited by proteins and organelles to attain asymmetric cellular distributions. In this project the regulation of MT polarity in fission yeast cells will be studied. In these cells, MTs are transported along one another by molecular motors whose action is opposed by a static MT crosslinker, ase1p. How cells regulate the counter opposing activities of sliding and crosslinking is largely unknown. The focus is on the formation of a bipolar array of MTs in interphase cells that is used as a model system for the more complex bipolar mitotic spindle. Using genetics tools the existing organization will be interfered. Molecular motors of different directionality will be expressed in combination with crosslinkers to investigate the spectrum of patterns that can be organized. In addition the role of direct molecular linkages between motors and crosslinkers will be investigated. It is not understood how these links contribute to pattern formation.
Julio Maia de OliveiraPhD, Laboratory of Plant Physiology, Wageningen University and Research Centre
Project title: Loss and reestablishment of desiccation tolerance in resurrection plants and seeds: new genes and networks
About my research
Anhydrobiosis ("life without water") is found across all biological kingdoms and desiccation tolerance of organisms is a highly relevant phenomenon in an ecological, social and economic context. It seems clear that global warming influences temperature extremes, thereby magnifying dry and wet seasons. This underlines DT as a relevant trait for crops, as well as wild plant species conservation. Many studies have aimed at understanding the mechanisms involved in the loss and acquisition of desiccation tolerance. However, in this field of research a knowledge gap still exists and many questions still need to be addressed: how can any organism survive complete drying? Why can some organisms tolerate extreme loss of water whereas others simply die after losing relatively small amounts of it? What are the structural, molecular, biochemical and genetic principles involved in this fascinating phenomenon? By bringgin light into these topics my aim is to find new genes and genetic networks involved on desiccation tolerance. This knowledge will be ultimatelly used in order to produce drought tolerant crops and new strategies for wild plant species conservation.
Nelson Davila OlivasPhD, Laboratory of Entomology, Wageningen University and Research Centre
Project title: Exploiting plant responses to combinatorial stresses
About my research
Biotic and abiotic stresses are major factors that impact the yielding capacity of our crops; reducing almost up to 80% of the yield potential in some crops. Considerable progress has been made towards the identification of genes that code for resistance to a single biotic or abiotic agent. Studies on mutants impaired in signalling through the phytohormones jasmonic acid, salicylic acid, abscisic acid and ethylene, triggered by biotic and abiotic stresses, have revealed antagonistic and synergistic interactions among them. It has been hypothesized that these interactions allow plants to respond to a combination of stresses in a tailor-made manner. However, until now both biotic and abiotic stresses have been addressed separately. By studying combinations of stresses have the potential of unravelling epistatic interactions between these signalling pathways. Since plants in natural conditions are exposed to a plethora of biotic and abiotic stresses simultaneously, they must hold a broad reservoir of adaptive mechanisms to multiple stresses. In this project we aim to explore natural variation in A. thaliana in adaptive defense to the necrotrophic fungus Botrytis cinerea, the chewing herbivore Pieris rapae and drought. For this purpose we will phenotype a collection of 360 A. thaliana ecotypes for resistance to individual and combined stresses. QTL’s responsible for the phenotypes will be mapped by Genome Wide Associations. Furthermore, -omics and signalling profiles will be generated for contrasting lines (i.e. susceptible vs. resistant). Mutants and overexpression lines will be generated for genes mapped by GWA. The integration of all data will help us to foster new insights into how plants adapt to the combined effect of pathogen infection, insect herbivores, and exposure to drought, and to convert this knowledge into novel tools for developing crops that are resistant to multiple stresses.
Jordi BoshovenPhD, Laboratory of Phytopathology, Wageningen University and Research Centre
Project title: The role of Verticillium dahliae Ave1 in fungal virulence and its recognition by the tomato Ve1 immune receptor.
About my research: V. dahliae is one of the most important plant pathogenic Verticillium species and causes wilt in artichoke, eggplant, pepper, potato, tomato, grape, olive, strawberry, chrysanthemum, sunflower, cotton, and flax. We study the interaction between V. dahliae and tomato (Solanum lycopersicum). A resistance locus was identified in tomato denoted as the Ve locus. Ve1 gives resistance to Verticillium race 1 but not to race 2 strains. Sequencing of race 1 and race 2 Verticillium strains resulted in a 50 kb region that is unique for race 1 strains. Subsequent RNA sequencing resulted in a single expressed open reading frame in this region which was called Ave1 (Avirulence on Ve1 tomato). Ave1 is recognized by tomato Ve1 and acts as a virulence factor. Ave1 homologs were mostly found in plants and only a few were found in fungi including Fusarium oxysporum f.sp. lycopersici, Cercospora beticola and Colletotrichum higginsianum suggesting that Ave1 is derived from plants by horizontal gene transfer. The goal of this project is to find out what the role of Ave1 is and if the Ave1 homologs are virulence factors.
Kathrin Lauss PhD, Nuclear Organization Group, Swammerdam Institute for Life Sciences, University of Amsterdam
Project title: Epigenetic mechanisms in plants.
About my research: Already since my early studies, regulation of gene expression and epigenetic mechanisms were quite fascinating for me. Despite extensive studies over the last years, many epigenetic mechanisms and phenomena (small RNA regulation, DNA methylation, paramutation etc) and their role in genome regulation are still not fully understood. Within Plant Sciences many questions related to epigenetics are still open, e.g. what effects does epigenetic regulation have on heterotic plant phenotypes? In my project, I am studying the contribution of epigenetic mechanisms to hybrid vigour in A. thaliana. I am focusing on small regulatory RNAs and DNA methylation profiles.