Growth promotion of a deep‐sea bacterium by sensing infrared light through a bacteriophytochrome photoreceptor

Summary Photoreceptors are found in all kingdoms of life and bacteriophytochromes (Bphps) are the most abundant photo‐sensing receptors in bacteria. Interestingly, BphPs have been linked to some bacterial physiological responses, yet most of the biological processes they regulate are still elusive, especially in non‐photosynthetic bacteria. Here, we show that a bacteriophytochrome (CmoBphp) from a deep‐sea bacterium Croceicoccus marinus OT19 perceives infrared light (wavelength at 940 nm) and transduces photo‐sensing signals to a downstream intracellular transduction cascade for better growth. We discover that the infrared light‐mediated growth promotion of C. marinus OT19 is attributed partly to the enhancement of pyruvate and propanoate metabolism. Further study suggests that CmoBphp plays a crucial role in integrating infrared light with intracellular signalling to control the bacterial growth and metabolism. This is the first report that deep‐sea non‐photosynthetic bacteria can sense infrared light to control growth through a bacteriophytochrome photoreceptor, thus providing new understandings towards light energy utilization by microorganisms.