title: Chloroplast avoidance movement reduces photodamage in plants.
abstract: When plants are exposed to light levels higher than those required for photosynthesis, reactive oxygen species are generated in the chloroplasts and cause photodamage. This can occur even under natural growth conditions. To mitigate photodamage, plants have developed several protective mechanisms. One is chloroplast avoidance movement, in which chloroplasts move from the cell surface to the side walls of cells under high light conditions, although experimental support is still awaited. Here, using different classes of mutant defective in chloroplast avoidance movement, we show that these mutants are more susceptible to damage in high light than wild-type plants. Damage of the photosynthetic apparatus and subsequent bleaching of leaf colour and necrosis occur faster under high light conditions in the mutants than in wild-type plants. We conclude that chloroplast avoidance movement actually decreases the amount of light absorption by chloroplasts, and might therefore be important to the survival of plants under natural growth conditions.
authors.affiliation: Division of Biological Regulation and Photobiology, National Institute for Basic Biology, Okazaki 444-8585, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kasahara
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Kagawa
authors.forename: Kazusato
authors.initials: K
authors.lastname: Oikawa
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Suetsugu
authors.forename: Mitsue
authors.initials: M
authors.lastname: Miyao
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Wada
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D002736:Chloroplasts / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects*; D017343:Genes, Plant / Q000235:genetics; D007700:Kinetics; D008027:Light; D045342:Light-Harvesting Protein Complexes; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009068:Movement / Q000528:radiation effects*; D009154:Mutation; D010641:Phenotype; D010788:Photosynthesis; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism; D018515:Plant Leaves / Q000166:cytology / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000975:Antioxidants; D029681:Arabidopsis Proteins; D045342:Light-Harvesting Protein Complexes; D008840:Microfilament Proteins; C423903:PHOT2 protein, Arabidopsis; D045322:Photosynthetic Reaction Center Complex Proteins; D017382:Reactive Oxygen Species; D002734:Chlorophyll