The Function and Regulon of Transcription Factor RcsA in <i>Pantoea</i> sp. YR343

Plants have a microbiome that hosts a variety of microorganisms, including pathogenic, neutral, and beneficial bacterial strains. These strains can influence the plant’s growth and health. Determining how the microbiome is recruited and structured and how these microbes communicate and interact with each other is needed to understand, and, ultimately, manipulate the effect of the microbiome on plant health. In order to pursue this goal, we are studying the plant-associated microbe Pantoea sp. YR343. Pantoea sp. YR343 is a motile and rod-shaped bacterium isolated from the roots of Populus deltoides- a promising source for biofuels. It possesses the ability to solubilize phosphate as well as produce the phytohormone indole-3-acetic acid (IAA). Moreover, Pantoea sp. YR343 shows both swimming and swarming motility, is a robust root colonizer, and induces lateral root production in Arabidopsis thaliana and Populus deltoides. As part of a genetic screen to identify factors that promote root colonization, we identified a transposon mutant that mapped to a gene encoding the transcription regulator RcsA. The transposon mutant displayed defects in biofilm formation, capsule production, and colonization of wheat roots, suggesting that it may influence the ability of Pantoea sp. YR343 to associate with plants. Understanding the function of this gene in Pantoea sp. YR343 provides insights into the regulation and mechanisms of plant association.