title: The stromal chloroplast Deg7 protease participates in the repair of photosystem II after photoinhibition in Arabidopsis.
abstract: Light is the ultimate source of energy for photosynthesis; however, excessive light leads to photooxidative damage and hence reduced photosynthetic efficiency, especially when combined with other abiotic stresses. Although the photosystem II (PSII) reaction center D1 protein is the primary target of photooxidative damage, other PSII core proteins are also damaged and degraded. However, it is still largely unknown whether degradation of D1 and other PSII proteins involves previously uncharacterized proteases. Here, we show that Deg7 is peripherally associated with the stromal side of the thylakoid membranes and that Deg7 interacts directly with PSII. Our results show that Deg7 is involved in the primary cleavage of photodamaged D1, D2, CP47, and CP43 and that this activity is essential for its function in PSII repair. The double mutants deg5 deg7 and deg8 deg7 showed no obvious phenotypic differences under normal growth conditions, but additive effects were observed under high light. These results suggest that Deg proteases on both the stromal and luminal sides of the thylakoid membranes are important for the efficient PSII repair in Arabidopsis (Arabidopsis thaliana).
authors.affiliation: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Xuwu
authors.initials: X
authors.lastname: Sun
authors.forename: Tingjiao
authors.initials: T
authors.lastname: Fu
authors.forename: Ning
authors.initials: N
authors.lastname: Chen
authors.forename: Jinkui
authors.initials: J
authors.lastname: Guo
authors.forename: Jinfang
authors.initials: J
authors.lastname: Ma
authors.forename: Meijuan
authors.initials: M
authors.lastname: Zou
authors.forename: Congming
authors.initials: C
authors.lastname: Lu
authors.forename: Lixin
authors.initials: L
authors.lastname: Zhang
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D008027:Light; D016254:Mutagenesis, Insertional; D009154:Mutation; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism*; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000378:metabolism* / Q000528:radiation effects; D020524:Thylakoids / Q000201:enzymology* / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D018744:DNA, Plant; D045332:Photosystem II Protein Complex; C036483:T-DNA; D010447:Peptide Hydrolases