Cell type-Specific Disease Resistance Against Vascular Xanthomonas Plant Pathogens

Descripción del proyecto

Un campo de batalla oculto contra las enfermedades vegetales

Las plantas no están indefensas, ya que cuenta con una coraza cerosa y una inmunidad de respuesta rápida. Sin embargo, algunos microorganismos patógenos pueden atravesar estas defensas sin ser detectados. Por ejemplo, las bacterias del género «Xanthomonas» aprovechan los hidatodos (pequeños poros que excretan savia en los márgenes de las hojas) y pueden burlar las defensas y secuestrar la vasculatura. Estos puntos de entrada no se han estudiado lo suficiente, lo que limita la comprensión de los mecanismos mediante los cuales las plantas protegen sus tejidos más vulnerables. El objetivo del proyecto XANTHORESIST, financiado por el Consejo Europeo de Investigación, es identificar receptores inmunitarios únicos y microbios protectores. Los investigadores llevarán a cabo estudios a escala celular empleando herramientas como la microdisección láser y la secuenciación de ARN de núcleos individuales. En conjunto, los investigadores diseñarán un plan genético para proteger el suministro mundial de alimentos.

Objetivo

Plants restrict entry of pathogens through physical barriers, and via Plants restrict the entry of pathogens through physical barriers and an innate immune system that recognizes pathogenic activity and initiates immune responses to halt the infection. As pathogens employ distinct infection strategies to invade plant tissues, immune responses are not uniform but rather specific for different cell and tissue types. This highlights the need to challenge the current concept of plant immunity and expand it towards a tissue-specific perspective. Vascular pathogens belonging to the bacterial genera Xanthomonas and Clavibacter exploit hydathodes –small multicellular organs at the leaf margin, which extrude xylem sap and are directly connected to the vasculature– as entry point into the plant.
Currently, we have little understanding of the immune mechanisms in hydathodes. To address this knowledge gap and overcome technical challenges of studying molecular processes in localized and low abundant hydathode tissue, I propose an ambitious and timely project using state-of-the-art approaches: 1) My goal is to identify elicitors, which are perceived by receptors in hydathodes, triggering immunity by using activity-guided screening of pathogen extracts and mass spectrometry. 2) I aim to isolate and characterise hydathode-inhabiting commensal microbes that play a role in plant protection by, amongst others, laser-microdissection of hydathode tissue and (spatial) microbiota profiling. 3) To dissect cell-specific responses towards pathogens and commensals and to identify hydathode-specific immune pathways, recently available single nucleus RNA sequencing combined with live-cell imaging of fluorescent reporters will be applied. Overall, hydathodes are a unique system to study both tissue-specificity of plant immunity and microbiota-mediated protection. Hence, this project will contribute to a comprehensive view of plant immunity and opens a path to novel plant protection strategies.