title: Constitutive accumulation of zeaxanthin in tomato alleviates salt stress-induced photoinhibition and photooxidation.
abstract: Zeaxanthin (Z) has a role in the dissipation of excess excitation energy by participating in non-photochemical quenching (NPQ) and is essential in protecting the chloroplast from photooxidative damage. To investigate the physiological effects and functional mechanism of constitutive accumulation of Z in the tomato at salt stress-induced photoinhibition and photooxidation, antisense-mediated suppression of zeaxanthin epoxidase transgenic plants and the wild-type (WT) tomato were used. The ratio of Z/(V + A + Z) and (Z + 0.5A)/(V + A + Z) in antisense transgenic plants were maintained at a higher level than in WT plants under salt stress, but the value of NPQ in WT and transgenic plants was not significantly different under salt stress. However, the maximal photochemical efficiency of PSII (Fv/Fm) and the net photosynthetic rate (Pn) in transgenic plants decreased more slowly under salt stress. Furthermore, transgenic plants showed lower level of hydrogen peroxide (H(2)O(2)), superoxide anion radical (O(2)(•-)) and ion leakage, lower malondialdehyde content. Compared with WT, the content of D1 protein decreased slightly in transgenic plants under salt stress. Our results suggested that the constitutive accumulation of Z in transgenic tomatoes can alleviate salt stress-induced photoinhibition because of the antioxidant role of Z in the scavenging quenching of singlet oxygen and/or free radicals in the lipid phase of the membrane.
authors.affiliation: College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong 271018, PR China.
authors.forename: Qiu-Yu
authors.initials: QY
authors.lastname: Zhang
authors.forename: Li-Yan
authors.initials: LY
authors.lastname: Wang
authors.forename: Fan-Ying
authors.initials: FY
authors.lastname: Kong
authors.forename: Yong-Sheng
authors.initials: YS
authors.lastname: Deng
authors.forename: Bin
authors.initials: B
authors.lastname: Li
authors.forename: Qing-Wei
authors.initials: QW
authors.lastname: Meng
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D006861:Hydrogen Peroxide / Q000378:metabolism; D008027:Light; D015227:Lipid Peroxidation; D018551:Solanum lycopersicum / Q000187:drug effects / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D008315:Malondialdehyde / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D010788:Photosynthesis / Q000187:drug effects / Q000528:radiation effects*; D045332:Photosystem II Protein Complex / Q000235:genetics; D018515:Plant Leaves; D030821:Plants, Genetically Modified; D016372:RNA, Antisense / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D036226:Seedlings; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological; D013481:Superoxides / Q000378:metabolism; D024341:Xanthophylls / Q000032:analysis / Q000378:metabolism*; D065146:Zeaxanthins
chemical_list: D000975:Antioxidants; D045332:Photosystem II Protein Complex; D016372:RNA, Antisense; D018749:RNA, Plant; D024341:Xanthophylls; D065146:Zeaxanthins; D013481:Superoxides; D002734:Chlorophyll; D012965:Sodium Chloride; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D010088:Oxidoreductases; C097153:zeaxanthin epoxidase