PhD in Biochemistry

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The bacterial pathogen Xanthomonas campestris pv. campestris (Xcc) causes black rot disease, a significant threat to cabbage crops worldwide. This pathogen enters the vascular system via hydathodes, tiny water pores of leaves that are connected to the xylem vein endings, and spreads systemically. Plants defend themselves against microbial invaders with an immune system involving pattern recognition receptors (PRR) at the cell surface that perceive immune elicitors (also known as MAMPs or DAMPs) activating plant immunity.

Currently, we have little understanding of the immune mechanisms in hydathodes and in the vasculature. Are there tissue-specific PRRs that contribute to resistance against Xcc? What are the cognate elicitors that activate PRR signalling? Does the plant detect also non-pathogenic bacteria in the hydathode?

Tasks and responsibilities

This project aims to identify immune elicitors (also known as MAMPs or DAMPs) as ligands of PRRs activating plant immunity during Xcc infection in the model plant Arabidopsis thaliana. You will screen for immune-eliciting molecules/proteins using plant immune assays and identify the elicitor by mass spectrometry. The receptor-ligand interaction will be further characterized by applying protein biochemistry methods. In addition, you will study plant resistance in different tissues by employing bioluminescent Xcc reporter strains that allow us to non-invasively track bacterial spread inside leaves. Lastly, you will investigate the relevance of the identified immune signalling pathway against pathogenic and commensal bacteria.

The overarching goal of this research is to deepen our understanding of the molecular interactions between vascular Xanthomonas and host plants. The findings of this project may ultimately support the development of Xanthomonas-resistant cabbage varieties through informed breeding strategies.