Optogenetic tools derived from plant photoreceptors

Nonvascular plants including algae possess an additional array of photoresponsive proteins since their aquatic environment has unique properties of light transmission. For instance, the unicellular green alga Chlamydomonas reinhardtii contains two archaeal types of rhodopsin that are activated by blue and green light, respectively [8-10]. Other unicellular photosynthetic organisms such as euglenids possess a novel class of photoreceptor identiƒed as a blue-light-activated adenylyl cyclase [11]. is wide selection of photoreceptors from both plant and algal sources o™ers diverse starting templates for synthetic engineering. Successful strategies based on the plant photoreceptors so far have been largely based on phototropin-related photoreceptors and the red-light-responding PHYs. Other notable examples have exploited the light-sensing mechanism of algal channelrhodopsin. e following sections aim to provide a brief summary regarding the structure and function of these photoreceptors before discussing their utility as tools to photomodulate and monitor cellular activities.