Microbial Community Interactions Affect Induced Systemic Resistance in Arabidopsis thaliana
S. HARRIS (1), J. Corwin (1), M. Feltcher (1), E. Shank (1), J. Dangl (1) (1) University of North Carolina at Chapel Hill, U.S.A.

Healthy plants maintain complex microbiomes, wherein microorganisms confer traits that increase the plant's overall fitness. Root colonization by certain microbes primes defense responses to increase resistance against foliar pathogens, a phenomenon termed Induced Systemic Resistance (ISR). Although ISR was originally discovered by isolating the biological agent of disease-suppressive soils and characterizing plant protection, field trials to recapitulate the protective phenotype often fail. This may be due to a preexisting soil microbiome, although mechanisms for the effects are unknown. Microorganisms elicit ISR by secretion of microbial volatile organic compounds (MVOCs). Recent work shows that bacteria produce different MVOCs when cultured under differing conditions or in combination with other bacteria. Our results suggest neighboring microbes influence production of MVOCs by ISR-eliciting bacteria, subsequently affecting the disease-resistance phenotype. We screened for native phytobiome bacteria that modulate ISR induction by MVOCs of Pseudomonas simiae WCS417r in the model plant Arabidopsis thaliana. Using mutants of both the bacteria and the plant, we explored genetic and biochemical bases for host response. Finally, we tested effects of abiotic environmental conditions on the ISR phenotype to better understand how the ISR response varies by growth setting. We anticipate this research may increase understanding of microbial interactions that affect plant phenotypes.

Abstract Number: P4-93
Session Type: Poster