Council members

PhD candidate at Plant Stress Resilience, Utrecht University & Plant Systems Physiology, Radboud University
Project: Mapping out site of action for ethylene-related root meristem hypoxia pre-adaptation

About my research
As climate change progresses, flooding events have become more frequent and intense. Flooding subjects plant roots to hypoxic (low oxygen) conditions, hindering gas exchange and leading to the accumulation of ethylene (volatile plant hormone), making this an important flood detection cue. Plant plasticity is especially important for plants in order to survive sub-optimal and stress conditions. Meristematic cells are key players in this because they are undifferentiated cells found at shoot and root tips with the potential to generate organs. The mechanisms behind meristem tolerance to stress conditions have yet remained underexplored. Previous experiments have shown that, in Arabidopsis, an ethylene pre-treatment following subsequent hypoxic stress can enhance root survival. While it is clear that the activating mechanism caused by ethylene accumulation boosts the regrowth capacity of roots after hypoxia, it is yet unknown how meristem protection is conferred. Is ethylene mediated by specific cell layers in the root? Do specific cell layers communicate signals in order to coordinate meristem protection?

My project focuses on elucidating the role of ethylene in conferring meristematic protection and to understand where exactly this is carried out in the root. For this, I use cell-type specific lines that have a disruption in ethylene signaling, and through imitating flooding conditions, study the survival effect on root tips. This is coupled with other reporter lines in order to be able to further understand what other players are involved in this meristematic protection during flooding conditions.

PhD candidate, Laboratory of Entomology, Wageningen University and Research
Project: Static but Plastic : Exploring plant defence strategies to deal with attack by multiple insect herbivores

About my research
In nature, plants are confronted with a plethora of insect herbivores which have been driving the evolution of plant defences for more than 400 million years. Plants have developed plastic defensive strategies to be resistant or tolerant against their diverse and, sometimes, unpredictable antagonist communities. While our understanding on plant-insect interactions has greatly improved over the past decade, most studies have focused on single or dual herbivore attack which do not capture the complexity of interactions occurring in natural ecosystems. Which growth-defence strategies plants may deploy to defend themselves under situation of attack by multiple herbivorous insects is largely unexplored. The aim of my PhD project is to investigate the plasticity of these defensive strategies within the Brassicaceae family, to understand the evolution of plant defences. Specifically, I explore how plants deal with sequential attack by multiple insects from different feeding guilds, how variation in time and space affects plant defence plasticity and how the different defence strategies vary between related plant species. For this, I am using transcriptomic and metabolic approaches, coupled with phenotypic measures on plant growth, reproduction, and insect performance.

PhD candidate in Evolutionary Plant Ecophysiology, University of Groningen
Project: It’s all about that pace; carbon distribution under resource limitation to maintain source-sink homeostasis.

About my research
Plants must adjust their growth rate or pace to ensure use of limited resources (sink strength) fits the environmental conditions (source capacity). For plants, growth and pacing concerns the production rate of new leaves, hence determining sink strength. Pace-control is a complex, highly plastic trait that involves a plethora of temporal changes across genetic, metabolic and physiological levels. For example, in harsh environments plants must drop their pace so sink strength aligns with the reduced source, and ensuring resource homeostasis. By adjusting pace, plants may adopt conservative or risky strategies to either avoid starvation or maximize resources, thus pacing is intrinsically linked to carbon metabolism and distribution throughout the plant. My PhD aims to dissect the mechanisms plants utilise to adjust their pace upon a drop source strength. I am currently focused on tracking carbon allocation/investment patterns throughout A. thaliana as well as exploring bi and perennial species that are able to utilize greater carbon storage flexibility than annuals. I will subsequently use transcriptomic approaches to start disentangling the underlying gene regulatory network in A. thaliana. Thus, hopefully bringing the highly plastic and resilient crops of the future one step closer.

PhD candidate, Plant Hormone Biology group, University of Amsterdam
Project: How do root-colonizing fungi sense plant roots?

About my research
Plants spend up to a third of their energy on the production of metabolites that are then exuded from the roots. These so-called root exudates act to shape the rhizosphere to the needs of the plant. For example, by modifying soil properties to be more favorable, but also by attracting and promoting the growth of certain microbes, leading to the establishment of a unique root microbiome. Some of these microbes are thought to be beneficial to the plant, whereas other can be detrimental. Root colonizing fungi are an important part of the root microbiome. Trichoderma species, for example, can benefit the plant by facilitating nutrient uptake and by attacking pathogenic fungi. Certain varieties of Fusarium species on the other hand, are pathogenic and can lead to devastating agricultural losses.

My work is focused on the signaling that occurs between lettuce and the root-colonizing fungi Trichoderma and Fusarium in the soil. I am trying to identify which molecules are present in lettuce root exudate, how the composition of this exudate changes during stress, and which molecules can elicit biological responses from the fungi. Simultaneously, I am trying to identify and characterize the receptors that the fungi use to perceive these signals.

PhD candidate, Laboratory of Entomology, Wageningen University & Research
Project: The plant-mediated ecological effects of parasitoids and their symbionts

About my research
Plants are under constant threat of attack by a wide range of insects herbivores. One way plants cope with this threat, is by releasing a “cry for help”: the plant will excrete volatile compounds to attract the natural enemies of the herbivore that is attacking. Parasitoid wasps are an example of such natural enemies and are widely used as a biocontrol agent in agriculture. Parasitoid wasps are carnivorous insects that lay their eggs in or on an insect host, sometimes with the help of symbiotic agents such as polydnaviruses and venom.  When a parasitoid wasp parasitises its host, the host undergoes a series of changes in both behaviour and physiology. Because of these behavioural and physiological changes, a plant may perceive a parasitised herbivore differently from a non-parasitised one and change its defensive response. An altered plant response following parasitism could influence the other organisms that are living on or in proximity of the affected plant. We know very little about what ecological consequences this change in plant response has on the rest of the insect-plant community, or what role these symbiotic agents may play in this effect.

In my project, I aim to explore the plant-mediated ecological effects that parasitoids and their symbionts have on the insect-plant community. By isolating the symbiotic agents of the parasitoids and micro-injecting them into the caterpillar host, I can specifically research their effect. I perform greenhouse studies to research the plant-mediated effect parasitoids have on the performance of insect herbivores; behavioral studies to look at the preference of heterospecific parasitoids; laboratory experiments to thoroughly explore the altered plant response through RNAseq, phytohormone-, glucosinolate- and volatile analyses; and finally, field studies to relate the results of the greenhouse and lab to the outside in practice.

PhD Candidate, Plant Stress Resilience & Experimental and Computational Plant Development, Utrecht University
Project: SIMs4StRes: Suberin Inducing Microbes for plant Stress Resilience?

About my research
Suberin deposition in the root has been proven to help the plant retain water under drought conditions, prevent oxygen loss in submerged plants, and block pathogens from infecting the roots. Suberin is thus a promising trait for enhancing plant multi-stress resilience. However, the effect of suberin is only beneficial when it is deposited in a specific spatial pattern, which also depends on environmental conditions. Engineering suberized barriers in plant remains thus challenging. Recently a novel class of microbes has been identified – Suberin Inducing Microbes (SIMs). Arthrobacter isolate VK49 enhanced suberin deposition in sorghum endodermis. The soil, from which SIMs were isolated was also suppressing infection with a parasitic plant, Striga. We aim to further test the potential of SIMs to promote resilience to other stresses and identify their mechanism of action.

PhD candidate, Plant Stress Resilience, Utrecht University
Project: Molecular Adaptation of Plants to High Altitude: Unravelling Genetic Survival Mechanisms

Climate change is a pressing issue, with rising temperatures affecting plants. A potential mitigating solution is cultivating crops at higher altitudes, where temperatures are lower. However, there are multiple environmental conditions that change across altitudes, such as partial pressure of oxygen, light and temperature. Temperature and light vary with latitude, while oxygen availability is primarily linked to altitude. This suggests that oxygen might play a key role in regulating the sensory mechanisms for both light and temperature at different altitudes. Plants detect oxygen through the PCO N-degron pathway, which regulates the ETHYLENE RESPONSE FACTOR (ERFVIIs) transcription factors. Under low atmospheric O₂ conditions, ERFVIIs become stabilized. Previous experiments have shown that plants from different altitudes display varying sensitivities to oxygen levels, resulting in differences in the stability of the ERFVIIs. Since the ERFVIIs are transcription factors, their target genes are differentially regulated contributing to plant adaptation at higher altitudes, which includes adaptation to higher light intensities and low temperature conditions.

Therefore, the main aim of my project is to understand how oxygen and the oxygen sensing mechanism regulate light and temperature responses, in terms of altitude adaptation. To investigate  this, I am using transcriptomic approaches and targeted proteomic tools to explore the interplay between those environmental factors and their role in driving altitude adaptation.

PhD candidate, Genetics, Wageningen University & Research
Project: LettuceKnow Project 2.2 “Genetics of abiotic stress resilience in lettuce”

About my research
It is well known that environmental factors such as light intensity, salinity levels and nutrient availability play an important role in plant growth and yield, yet the molecular mechanisms and genetic architecture that underline the responses of plants to said conditions are still largely unknown. With climate change causing erratic weather patterns, arable land with ideal environmental conditions is becoming an increasingly scarce resource. This necessitates the need to identify stress resilience loci and develop stress resistant crops. An important, yet underutilized avenue that can be used for identification of novel stress resilience loci is by mining the extended germplasm of crops thus exploring and exploiting its existing natural genetic variation. This approach has been used extensively in Arabidopsis thaliana but in the case of lettuce the use has been limited to the search for immunity related traits. With the advent of high throughput phenotyping technologies that can phenotype a large number of plants continuously across multiple days, phenotyping complex traits linked to abiotic stress can be more robustly captured. This, combined with powerful integrative bioinformatics and machine learning could help describe the genetic background of abiotic stress resilience in lettuce.

In a nutshell, my project a part of the larger LettuceKnow project aims “To identify and exploit natural variation in the LK500 population to improve lettuce resilience to abiotic stress conditions specifically fluctuating light and tipburn inducing growth conditions while reducing the trade-off towards plant growth”.

PhD candidate, Plant Breeding, Wageningen University & Research
Project: Breeding for improved yield and attachment of the sugar kelp Saccharina latissima

About my research
We currently need almost half of the land surface to produce plant and animal based food and this percentage has to increase to ensure food security in the future. The world population continues to grow and simultaneously agricultural yield is expected to decrease due to soil degradation, exhaustion of natural resources and extreme weather events. The sea provides opportunity to produce seaweed for food without relying on irrigation with fresh water, high quality arable land, and in some cases fertilisers. However, seaweed farming in the North Sea is not yet economically feasible. The challenge to make the seaweed sector profitable is two-fold – unpredictable, low yields and high production costs. Limited breeding efforts for Saccharina latissima, the sugar kelp species native to the North Sea, hampered improvement of yield and yield stability. There is currently little understanding of the genetics determining complex yield traits and there are limited tools available for high-throughput screening of yield of S. latissima. By high-throughput screening the natural variation that exists we can unravel yield related physiological processes that evolved naturally. Besides low yields, production costs associated with the current cultivation method predominantly used in Asia are high. To reduce production costs, the European seaweed sector wants to shift to a so-called direct seeding method, however farmers have observed high losses of up to 99% of the seeding material. To reduces these losses, attachment of seaweed to the ropes should be enhanced. By acquiring knowledge of the genetics underlying the complex traits yield and attachment, breeders will be able to provide farmers with more robust starting material. During my PhD, I will develop a high-throughput phenotyping method for yield and perform a genome-wide association study (GWAS) for yield and attachment with over 200 different S. latissima genotypes from 34 locations.

PhD candidate, Plant Develpmental Systems, Wageningen University & Research
Project: Machine learning-based prediction of transcription factor protein-protein interactions

About my research
Plants use transcription factors to regulate all developmental processes occurring throughout their lifecycle. One family of transcription factors seems to be overly present in these proteins, namely: the MADS-box proteins. These proteins are all highly similar in structure, but have a highly diverse interaction pattern. SOC1, for instance, is capable of interacting with circa 25 other MADS box transcription factors, whereas the highly similar AGL14 interacts with only 4 proteins. In my research, the aim is to understand where the specificity of these protein-protein interactions comes from. We use machine learning to predict what motifs could be of influence. Ultimately, this research should contribute to predicting interaction specificity for other transcription factors.

PhD Candidate, Cell & Developmental Biology, Wageningen University & Research
Project: At the root of drought resilience: genetic adaptation of Arabidopsis root systems to mild drought

About my research
Annual drought is becoming increasingly frequent and less predictable. Shortage of water at any point during a plant’s life cycle is detrimental, causing yield losses or growth delays. To survive and thrive periods of these suboptimal environmental conditions, plants use their roots to scavenge for water. Their root system architecture determines how much of the soil is available to them to scavenge in. Therefore, a robust and adaptable root system might be part of the key to a plant capable of withstanding water shortages for longer with less detriment to its growth. To this end, I study how Arabidopsis thaliana has adapted its root systems to survive across different climates with varying levels of water availability. I hope to find genetic adaptations that allow for changes in the root system architecture and how these changes in root system architecture can alleviate drought stress during a plant’s life cycle. To do so, I am doing a large-scale GWAS in rhizotrons, combined with transcriptomics to find out which genes are responsible for drought responsive changes in a plant’s root system architecture.

PhD candidate, Plant-Microbe Interactions, Utrecht University
Project: The identification of candidate genes in the interaction between Arabidopsis and plant-growth promoting rhizobacteria.

Beneficial microbes in the microbiome of plants can serve as their allies, by stimulating plant growth and enhancing defense against pathogens. These beneficial microbes are collectively referred to as plant-growth promoting rhizobacteria (PGPR). The PGPR Pseudomonas simiae WCS417 can colonize Arabidopsis thaliana roots, resulting in morphological changes in both its roots and shoots. These changes include an increase in shoot fresh weight, alongside an increase in primary root length and the number of lateral roots. It has been established that not all Arabidopsis accessions respond equally to WCS417; the morphological changes in some accessions are much more pronounced than in others. This indicates natural variation in the ability of Arabidopsis to benefit from an interaction with WCS417.

The aim of my project is to improve our understanding of what Arabidopsis genes are important in its response to WCS417. We expect to find candidate genes by conducting a Genome-wide association study (GWAS) on a large collection of natural Arabidopsis accessions. I will use the high-throughput imaging facilities from NPEC to generate the large amount of phenotypic data required for the GWAS. My research may contribute to the development of future crops optimized in benefiting from the positive effect from PGPR’s.