Chloroplast Photorelocation Movement

Abstract

Chloroplast photorelocation movement is one of the best-characterized plant organelle movements and is found in various plant species from alga to flowering plants. In general, low-intensity blue light induces a chloroplast accumulation response for efficient light capture and high-intensity blue light induces an avoidance response so that chloroplasts can avoid photodamage. Red light is also effective in some alga, moss, and fern species. It was shown that phototropin (phot) is a blue light receptor in land plants and neochrome (neo), which is a chimera photoreceptor between phytochrome and phototropin, is a red light receptor in ferns and possibly in alga. Although the signal transduction pathways and motility system of chloroplast movement is not clearly understood, several components involved in signaling or motility were identified through molecular genetic research using Arabidopsis thaliana and the involvement of actin filaments in the motility system is obvious in most plant species. This chapter summarizes the current progress in research on chloroplast photorelocation movement.