Synthetic communities dissect bacterial contributions to plant phenotypes
S. HERRERA PAREDES (1), G. Castrillo Molina (2), J. Macalino Esteban (2), P. Pereira Lima Teixeira (2), M. Feltcher (2), E. Getzen (2), C. Jones (2), J. Dangl (2) (1) The University of North Carolina at Chapel Hill, U.S.A.; (2) The University of North Carolina at Chapel Hill, U.S.A.

Plants and microbes may form any ecological interaction, from antagonism to mutualism. Research focusing on binary interactions (when one plant and one microbial species are considered) has revealed an impressive amount of molecular details that explain the mechanisms behind these interactions. However, in nature plant-microbe interactions occur in the background of a complex biotic environment. We developed an experimental design approach, termed bacterial combinatorics, that systematically varies the bacterial community faced by the plant, while retaining enough statistical power to identify bacteria that alter specific plant phenotypes. We coupled this approach with image-based plant phenotyping, and showed that we can identify bacteria that alter plant size and color; furthermore, we quantified the degree of bacterial additivity on these phenotypes, and found that plant size differences are explained mainly by additive bacterial effects; in contrast, interactions are needed to explain differences in plant color. A variant of these approach, termed bacterial rolling circle, demonstrated that data from binary association experiment (one plant and one bacteria species ) informs synthetic community designs to alter phosphate accumulation in plants; in line with our results for plant size, we found that bacterial additive effects are sufficient to explain most differences. Plant transcriptomes will indicate what plant genes and pathways mediate the bacterial effects, and ultimately lead to genetic and molecular mechanisms that are representative of interactions in nature's complexity.

Abstract Number: P4-94
Session Type: Poster