Photomovements based on the flagellar motility in the green alga Chlamydomonas reinhardtii

Abstract

The freshwater unicellular green alga Chlamydomonas reinhardtii is a model organism in various research fields such as flagellar motility, photosynthesis, and photomovements. Its photomovements (phototaxis and photophobic response) are remarkable cellular responses that include photoreception at the eyespot and following modulation of flagellar motility. Regulation of photomovements is important for cells to inhabit under suitable light conditions for photosynthesis; however, its molecular basis is poorly understood. We have studied how phototaxis and photophobic response are regulated, and found that cellular redox (reduction-oxidation) poise, which alters in response to changes in photosynthesis/respiratory activities, is a key signal. Here we summarize our recent study on redox regulation of Chlamydomonas photomovements.