title: HYPERSENSITIVE TO HIGH LIGHT1 interacts with LOW QUANTUM YIELD OF PHOTOSYSTEM II1 and functions in protection of photosystem II from photodamage in Arabidopsis.
abstract: Under high-irradiance conditions, plants must efficiently protect photosystem II (PSII) from damage. In this study, we demonstrate that the chloroplast protein HYPERSENSITIVE TO HIGH LIGHT1 (HHL1) is expressed in response to high light and functions in protecting PSII against photodamage. Arabidopsis thaliana hhl1 mutants show hypersensitivity to high light, drastically decreased PSII photosynthetic activity, higher nonphotochemical quenching activity, a faster xanthophyll cycle, and increased accumulation of reactive oxygen species following high-light exposure. Moreover, HHL1 deficiency accelerated the degradation of PSII core subunits under high light, decreasing the accumulation of PSII core subunits and PSII-light-harvesting complex II supercomplex. HHL1 primarily localizes in the stroma-exposed thylakoid membranes and associates with the PSII core monomer complex through direct interaction with PSII core proteins CP43 and CP47. Interestingly, HHL1 also directly interacts, in vivo and in vitro, with LOW QUANTUM YIELD OF PHOTOSYSTEM II1 (LQY1), which functions in the repair and reassembly of PSII. Furthermore, the hhl1 lqy1 double mutants show increased photosensitivity compared with single mutants. Taken together, these results suggest that HHL1 forms a complex with LQY1 and participates in photodamage repair of PSII under high light.
authors.affiliation: State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275 Guangzhou, People's Republic of China.
authors.forename: Honglei
authors.initials: H
authors.lastname: Jin
authors.forename: Bing
authors.initials: B
authors.lastname: Liu
authors.forename: Lujun
authors.initials: L
authors.lastname: Luo
authors.forename: Dongru
authors.initials: D
authors.lastname: Feng
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Qingen
authors.initials: Q
authors.lastname: Da
authors.forename: Yanming
authors.initials: Y
authors.lastname: He
authors.forename: Kangbiao
authors.initials: K
authors.lastname: Qi
authors.forename: Jinfa
authors.initials: J
authors.lastname: Wang
authors.forename: Hong-Bin
authors.initials: HB
authors.lastname: Wang
mesh_terms: D017360:Arabidopsis / Q000378:metabolism* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D009154:Mutation; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D011485:Protein Binding; D019704:Protein Disulfide-Isomerases / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C577259:LQY1 protein, Arabidopsis; D008565:Membrane Proteins; D045332:Photosystem II Protein Complex; D017382:Reactive Oxygen Species; D019704:Protein Disulfide-Isomerases