Postdoc Unravelling the Role of the Plant Microbiota in Hydathodes for Disease Resistance

Are you intrigued by the interactions between plants, their microbiota and pathogens? Do you have a passion for unravelling the function of the plant microbiota going beyond descriptive studies and obtain a mechanistic understanding of how commensal microbes contribute to disease resistance? We invite enthusiastic and dedicated post-doctoral candidates to join our curiosity-driven research team to delve into the fascinating world of plant hydathodes, commensal bacteria, and Xanthomonas pathogens.

Join us!
Vascular Xanthomonas pathogens have a unique leaf-infection strategy. These bacteria exploit hydathodes to enter the xylem vasculature and to spread systemically resulting in disease development. Hydathodes are tiny organs at the leaf margin acting as water pores providing access to a sub-epidermal cavity filled with epithem cells interspersed with xylem vein-endings. The organs function as overpressure valves to release excess water by excreting xylem sap. Hydathode pores are constitutively open, and the excreted xylem sap contains nutrients that support microbial growth. Therefore, hydathodes represent an important interface between the leaf surface and its interior and are likely colonised by commensal bacteria as well. The underlying hypothesis of this project is that hydathode-adapted commensals play a role in protecting a plant against vascular pathogens.

Tasks and responsibilities
The goal of this project is to identify commensal bacteria in hydathodes, and to characterize their role in plant protection. Going beyond descriptive microbiota analysis from entire leaves, you will isolate bacteria exclusively from hydathode tissue using laser-microdissection to establish a dedicated collection of hydathode-adapted bacteria. Fluorescence in situ hybridization (FISH) probes and highly sensitive 16S rRNA amplicon sequencing will allow us to assess the spatial distribution and taxonomic diversity of the hydathode microbiota. The bacterial isolates will be used in microbiota reconstitution experiments to test their involvement in disease resistance under controlled conditions.

Our model system is the bacterial pathogen Xanthomonas campestris pv. campestris (Xcc), which causes black rot disease in cabbage (Brassica oleracea) and in Arabidopsis thaliana. Both plant species will be used in the project.

In complementary projects in our group, we are investigating the molecular mechanism of plant immunity in hydathodes. The combined insights in hydathode immunity and the microbiota will contribute to a comprehensive understanding of plant resistance against Xcc and will potentially lead to novel strategies for plant protection and resistance breeding.

This project will be carried out in the Molecular Plant Pathology group, part of the Green Life Sciences theme at the Swammerdam Institute for Life Sciences. Research in our group aims at advancing fundamental knowledge of the interactions between plants and their pathogens, using state-of-the-art methods in molecular biology, genetics, biochemistry, and microbiology. In addition, we seek opportunities to translate fundamental insights of plant-pathogen interactions into solutions to enhance disease resistance in crops by collaborating with plant breeding companies. The position is supported by a recently awarded ERC Starting grant.

You will:

• Isolate bacteria specifically from hydathodes using laser-microdissection and establish a strain collection from cabbage-associated bacteria;
• apply 16S rRNA amplicon sequencing and fluorescence in situ hybridization (FISH) staining of leaf thin-sections to characterize the diversity of bacteria inside hydathodes;
• use microbiota reconstitution experiments to test the role of commensal bacteria in disease protection against Xcc;
• perform your experiments in a systematic and controlled manner and keep records by properly documenting and organizing your work;
• be an active member of the research group, give feedback to others and take responsibility for shared tasks;
• discuss your work with members of the group and the UvA plant science community to incorporate feedback;
• take a leading role in writing manuscripts for publication in peer-reviewed journals;
• supervising Bachelor and Master internships, as well as co-supervising a lab technician.

Ownership and Initiative: We are particularly interested in candidates who can take ownership of their research project and demonstrate initiative in driving their work forward. As postdoc, you will have the opportunity to shape the direction of your research and contribute novel ideas to the field.

You will get the opportunity to:

• present your results at (inter)national scientific conferences;
• expand you academic, professional, and personal skills;
• thrive in a team that values impactful research and mutual support;
• contribute to science communication and outreach activities;
• get access to state-of-the art research facilities at UvA and collaboration partners;
• participate in training courses of the University of Amsterdam and the Dutch Experimental School of Plant Sciences (EPS).

Your profile
You are passionate about science and have a particular interest in plant microbiomes with a special focus on plant protection against pathogens. You enjoy performing experimental lab work (e.g. microbiota profiling, large-scale isolation of bacteria, disease assays with plants and constructing synthetic communities), as well as metagenome data analysis. You have a creative mind and look forward to learning and applying your skills and knowhow in your project. Finally, you are a team player and a pleasant colleague who enjoys being part of an international team of plant scientists.

Your experience
You have/are

• a PhD degree in molecular plant biology, microbiology or host-associated microbiomes;
• demonstrated hands-on experience with some of the following techniques and skills: 16S amplicon sequencing, fluorescent/confocal microscopy, FISH staining, large-scale isolation/culturing of bacteria, synthetic community experiments, plant growth and inoculations;
• fluent in English, both written and spoken.

Our offer
We offer a temporary contract for 38 hours per week for the duration of 12 months. Upon a good evaluation this will be extended with another 24 months/ The preferred starting date is February 1st 2026.

The gross monthly salary, based on 38 hours per week and dependent on relevant experience, ranges between €3.546 to €5.538. This does not include 8% holiday allowance and 8,3% year-end allowance. The UFO profile PhD candidate applicable.

The Collective Labour Agreement of Universities of the Netherlands is applicable.

Besides the salary and a vibrant and challenging environment at Amsterdam Science Park we offer you multiple fringe benefits:

• 232 holiday hours per year (based on fulltime);
• multiple courses to follow from our Teaching and Learning Centre;
• a pension at ABP for which UvA pays two third part of the contribution;
• the possibility to follow courses to learn Dutch;
• help with housing for a studio or small apartment when you’re moving from abroad.

Are you curious to read more about our extensive package of secondary employment benefits, take a look here.

Where you will work
The Swammerdam Institute for Life Sciences (SILS) is located at the vibrant Amsterdam Science Park. SILS is one of eight institutes of the University of Amsterdam's Faculty of Science (FNWI). With around 240 employees, SILS carries out internationally high-quality life science research and provides education within various university programs. Research is also carried out in close cooperation with the medical, biotech, chemical, flavor, food & agricultural, and high-tech industries, and revolves around 4 main themes, Cell & Systems biology, Neurosciences, Microbiology and Green Life Sciences.

If you feel the profile fits you, and you are interested in the job, we look forward to receiving your application. We accept applications until and including 30 November 2025. Applications should include the following information (all files besides your CV should be submitted in one single pdf file):

• a detailed CV including the months (not just years) when referring to your education and work experience;
• a letter of motivation;
• the names and email addresses of two references (will be contacted later during the interview process).

A knowledge security check can be part of the selection procedure (for details: National knowledge security guidelines).

Do you have any questions or do you require additional information? Please contact:

• dr. Sebastian Pfeilmeier, Assistant Professor
• Email: j.s.pfeilmeier@uva.nl