Evolution of the Cp-Actin-based Motility System of Chloroplasts in Green Plants.

Noriyuki Suetsugu,Masamitsu Wada

doi:10.3389/fpls.2016.00561

Noriyuki Suetsugu, Masamitsu Wada

Open Access

https://doi.org/10.3389/fpls.2016.00561

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Abstract

During the course of green plant evolution, numerous light responses have arisen that optimize their growth under fluctuating light conditions. The blue light receptor phototropin mediates several photomovement responses at the tissue, cellular and organelle levels. Chloroplast photorelocation movement is one such photomovement response, and is found not only in most green plants, but also in some red algae and photosynthetic stramenopiles. In general, chloroplasts move toward weak light to maximally capture photosynthetically active radiation (the chloroplast accumulation response), and they move away from strong light to avoid photodamage (the avoidance response). In land plants, chloroplast movement is dependent on specialized actin filaments, chloroplast-actin filaments (cp-actin filaments). Through molecular genetic analysis using Arabidopsis thaliana, many molecular factors that regulate chloroplast photorelocation were identified. In this Perspective, we discuss the evolutionary history of the molecular mechanism for chloroplast photorelocation movement in green plants in view of cp-actin filaments.

Highlights

Green plants have made many evolutionary innovations, moving from aquatic to terrestrial habitats, with multiple evolutions of multicellularity, and complex multicellular development
We have demonstrated that these eight proteins are essential for chloroplast movement and positioning via cp-actin filaments
Because chloroplast movement is found universally in green algae and land plants, we subsequently investigated whether the molecular factors identified in A. thaliana are conserved across green algae and land plants

Summary

Introduction

Green plants (land plants and green algae) have made many evolutionary innovations, moving from aquatic to terrestrial habitats, with multiple evolutions of multicellularity, and complex multicellular development. MOVEMENT IMPAIRED 1 (PMI1; DeBlasio et al, 2005); a glutaredoxin-like protein THRUMIN 1 (THRUM1; Whippo et al, 2011); an auxilin-like protein J-DOMAIN PROTEIN REQUIRED FOR CHLOROPLAST ACCUMULATION RESPONSE 1 (JAC1; Suetsugu et al, 2005); two related coiledcoil proteins WEB1 (WEAK CHLOROPLAST MOVEMENT UNDER BLUE LIGHT 1) and PMI2 (PLASTID MOVEMENT IMPAIRED 2; Luesse et al, 2006; Kodama et al, 2010).

Results

Conclusion