The Arabidopsis leaf transcriptome reveals distinct but also overlapping responses to colonization by phyllosphere commensals and pathogen infection with impact on plant health.
Plants are colonized by a variety of bacteria, most of which are not pathogenic. Currently, the plant responses to phyllosphere commensals or to pathogen infection in the presence of commensals are not well understood. Here, we examined the transcriptional response of Arabidopsis thaliana leaves to colonization by common commensal bacteria in a gnotobiotic system using RNA sequencing and conducted plant mutant assays. Arabidopsis responded differently to the model bacteria Sphingomonas melonis Fr1 (S.Fr1) and Methylobacterium extorquens PA1 (M.PA1). Whereas M.PA1 only marginally affected the expression of plant genes (< 10), S.Fr1 colonization changed the expression of almost 400 genes. For the latter, genes related to defense responses were activated and partly overlapped with those elicited by the pathogen Pseudomonas syringae DC3000 (Pst). As S.Fr1 is able to mediate plant protective activity against Pst, we tested plant immunity mutants and found that the pattern-recognition co-receptor mutant bak1/bkk1 showed attenuated S.Fr1-dependent plant protection. The experiments demonstrate that the plant responds differently to members of its natural phyllosphere microbiota. A subset of commensals trigger expression of defense-related genes and thereby may contribute to plant health upon pathogen encounter.
['Vogel|Christine|C|', 'Bodenhausen|Natacha|N|', 'Gruissem|Wilhelm|W|', 'Vorholt|Julia A|JA|']
D017360:Arabidopsis D053898:Biosynthetic Pathways D015169:Colony Count, Microbial D003300:Copper D018506:Gene Expression Regulation, Plant D017343:Genes, Plant D006706:Homeostasis D020580:Methylobacterium D009154:Mutation D018384:Oxidative Stress D018515:Plant Leaves D044224:Pseudomonas syringae D012333:RNA, Messenger D015398:Signal Transduction D020578:Sphingomonas D014158:Transcription, Genetic D059467:Transcriptome
Arabidopsis commensal bacteria plant protection microbe-associated molecular pattern (MAMP) plant microbiota plant pathogen transcriptional profiling