Leaf transcriptomics reveals differing responses of Arabidopsis to colonization by ubiquitous phyllosphere colonizers with potential implications for plant health upon pathogen encounter
C. VOGEL (1), N. Bodenhausen (2), W. Gruissem (3), J. Vorholt (2) (1) Institute of Microbiology, ETH Zurich, Switzerland; (2) Institute of Microbiology, ETH Zurich, Switzerland; (3) Institute of Agricultural Sciences, ETH Zurich, Switzerland

Plants are colonized by a variety of microorganisms, the plant microbiota. At present the plant responses to its microbiota or to pathogen infection in the presence of commensals are not well understood. We examined the transcriptional response of Arabidopsis thaliana leaves to colonization by representatives of the bacterial phyllosphere core microbiota in a gnotobiotic system using RNA sequencing. Arabidopsis responded differently to colonization by the two model bacteria Sphingomonas melonis Fr1 and Methylobacterium extorquens PA1. Whereas little change in gene expression was observed in plants colonized by PA1, the expression of almost 400 plant genes was altered in response to Fr1. The transcriptional response of Arabidopsis to Fr1 partly overlapped with the one elicited by the pathogen Pseudomonas syringae DC3000. Fr1 is known to confer protection against P. syringae to its host. We have therefore started to investigate whether plant protection is affected in different plant hormone signaling and immune system mutants. Our experiments demonstrate that the plant responds to its microbiota and a subset of commensals may increase expression of defense-related genes and contribute to plant health and performance.

Abstract Number: C16-3, P5-135
Session Type: Concurrent