A plant-pathogen-microbiome disease triangle concept   
J. KREMER (1), B. Paasch (2), S. He (3), J. Tiedje (4), B. Kvitko (5), J. Jerome (2) (1) Michigan State University, U.S.A.; (2) DOE Plant Research Laboratory, Michigan State University, U.S.A.; (3) Howard Hughes Medical Institute, Michigan State University DOE Plant Research Laboratory, U.S.A.; (4) Michigan State University Center for Microbial Ecology, U.S.A.; (5) University of Georgia Department of Plant Pathology, U.S.A.

Historically, plant-microbe interaction studies have been performed in the presence of endogenous microbiota. It is not known whether observed plant immunity and pathogen virulence phenotypes are dependent on the presence and composition of the plant microbiome. We are interested in understanding the “hidden” role of endogenous microbiota in the context of a tritrophic plant-pathogen-microbiome interaction. To perform a functional analysis of microbe-free versus colonized Arabidopsis, we developed the FlowPot axenic soil-based plant growth system. Herein, we report that endogenous plant microbiota contribute to (i) host immunocompetency and (ii) the infectious potential of Pseudomonas syringae pv tomato DC3000 (Pst). Transcriptome profiling of microbe-free and colonized Arabidopsis revealed colonized plants have significantly more “defense-associated” transcripts involved in innate immunity, SA signaling, and REDOX homeostasis. Upon Pst infection, dual RNA-seq revealed microbiome-influenced host and pathogen gene expression. Via gene-targeted metagenomics, we identified correlations between host transcripts and microbiome composition. Phenotypic analyses and immune perturbations revealed microbe-free plants are partially compromised in the ability to respond to MAMPs and benzothiadiazole, and exhibit defense hormone dysbiosis. Collectively, we suggest a plant-pathogen-microbiome disease triangle concept for future study of microbial pathogenesis and plant disease resistance.

Abstract Number: P4-97
Session Type: Poster