title: The unsaturation of phosphatidylglycerol in thylakoid membrane alleviates PSII photoinhibition under chilling stress.
abstract: Over-expression of chloroplast glycerol-3-phosphate acyltransferase gene (LeGPAT) in tomato increased cis-unsaturated fatty acid content in phosphatidylglycerol (PG) of the thylakoid membrane. Under chilling stress, the oxygen evolving activity, the maximal photochemical efficiency of PSII (F (v)/F (m)), and superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities decreased less in sense lines than in antisense lines compared to wild-type (WT) plants. Consistently, the relative electric conductivity, O⁻₂and H(2)O(2) contents in sense lines were lower than those of WT and antisense lines. The antisense lines with low level of unsaturated fatty acids in PG were extremely susceptible to photoinhibition of PSII and had a significant reduction in the D1 protein content of PSII reaction center under chilling stress. However, in the presence of streptomycin (SM), the degradation of D1 protein was faster in sense lines than in WT and antisense plants. These results suggested that, under chilling stress conditions, increasing cis-unsaturated fatty acids in PG through over-expression of LeGPAT can alleviate PSII photoinhibition by accelerating the repair of D1 protein and improving the activities of antioxidant enzymes in chloroplasts.
authors.affiliation: College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, 271018, People's Republic of China.
authors.forename: Xiao-lin
authors.initials: XL
authors.lastname: Sun
authors.forename: Sha
authors.initials: S
authors.lastname: Yang
authors.forename: Li-Yan
authors.initials: LY
authors.lastname: Wang
authors.forename: Qiu-Yu
authors.initials: QY
authors.lastname: Zhang
authors.forename: Shi-Jie
authors.initials: SJ
authors.lastname: Zhao
authors.forename: Qing-Wei
authors.initials: QW
authors.lastname: Meng
mesh_terms: D060387:Ascorbate Peroxidases / Q000378:metabolism; D002734:Chlorophyll / Q000032:analysis; D003080:Cold Temperature; D004553:Electric Conductivity; D005227:Fatty Acids / Q000032:analysis; D005992:Glycerol-3-Phosphate O-Acyltransferase / Q000235:genetics / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D008027:Light; D018551:Solanum lycopersicum / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000528:radiation effects; D010715:Phosphatidylglycerols / Q000378:metabolism*; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000528:radiation effects; D013482:Superoxide Dismutase / Q000378:metabolism; D020524:Thylakoids / Q000378:metabolism*
chemical_list: D005227:Fatty Acids; D010715:Phosphatidylglycerols; D045332:Photosystem II Protein Complex; D002734:Chlorophyll; D006861:Hydrogen Peroxide; D060387:Ascorbate Peroxidases; D013482:Superoxide Dismutase; D005992:Glycerol-3-Phosphate O-Acyltransferase