A Bacteriophytochrome Mediates Interplay between Light Sensing and the Second Messenger Cyclic Di-GMP to Control Bacterial Social Behaviors

Abstract

Bacteriophytochromes are the most abundant and ubiquitous light sensing receptors in bacteria and are involved in time-of-day behavior or responses. However, their biological and regulatory role in non-photosynthetic bacteria is poorly understood, and even less is known about how it regulates diverse cellular processes. Here we show that a bacteriophytochrome (XooBphP), from the plant pathogen Xanthomonas oryzae pv. oryzae, perceives light signal and transduces through its EAL-mediated phosphodiesterase activity, modulating the intracellular level of the ubiquitous bacterial second messenger c-di-GMP. We discover that the light mediated fine-tuning of the intracellular c-di-GMP levels by XooBphP regulate the production of virulence associated functions, iron metabolism and transition of sessile to free-swimming motile lifestyle, contributing to the host colonization and virulence. Altogether, our results reveal that XooBphP plays a crucial role in integrating photo-sensing with intracellular signaling to control pathogenic lifestyle and bacterial social behaviors.