Light as a regulatory environmental factor

Sunlight regulates many environmental processes, but in particular the high-energy blue light region represents a threat that has to be detected with high confidence and to which organisms have to respond in an appropriate physiological manner. Based on in vitro investigations that reveal the molecular processes of blue light (BL)-sensitive photoreceptors, their regulatory function for microbial communities is outlined. Interestingly, the presence of BL photoreceptors coincides with blue light-induced photolyases that repair DNA lesions, and also with proteins involved in the iron metabolism pathway.