P-331 - Examining the impact of ACC deaminase mediated modulation of ethylene in bioenergy and model plants

Microbiomes play important roles for their plant hosts by impacting nutrient acquisition, phytohormone modulation, and pathogen suppression. ACC-deaminase, a microbial enzyme in both bacteria and fungi, reduces plant ethylene levels rendering plants more resilient to stress. While this plant growth promoting trait has efficacy across diverse plants, the importance of ACC deaminase in diverse microbial communities across developmental stages and during drought remains unclear. Therefore, we created two synthetic communities (SynComs) of bacteria and fungi that differ in their ACC deaminase activity. In Arabidopsis thaliana studies, we inoculated seedlings with our two SynComs and harvested plants at various growth stages to examine differences in ACC-deaminase activity, community composition and plant physiology. We observed plants inoculated with the SynCom with ACC deaminase activity exhibited slower development and increased biomass compared to other treatment groups. In a second set of studies, we inoculated on switchgrass with our two SynComs to determine if microbial ACC deaminase activity again correlates with increased biomass and prolonged vegetative developmental stages during drought in the greenhouse. These studies allow us to establish if microbial ACC-deaminase activity robustly increases biomass for a bioenergy crop that regularly faces drought stress This work expands our knowledge on the translation potential of a microbial mechanism impacting plant health.