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Constitutive accumulation of zeaxanthin in tomato alleviates salt stress-induced photoinhibition and photooxidation

Authors

  • Qiu-Yu Zhang,

    1. College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an, Shandong 271018, P.R. China
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  • Li-Yan Wang,

    1. College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an, Shandong 271018, P.R. China
    2. Department of Biology, Dezhou University, Dezhou, Shandong 253023, P.R. China
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  • Fan-Ying Kong,

    1. College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an, Shandong 271018, P.R. China
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  • Yong-Sheng Deng,

    1. College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an, Shandong 271018, P.R. China
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  • Bin Li,

    1. College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an, Shandong 271018, P.R. China
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  • Qing-Wei Meng

    Corresponding author
    1. College of Life Science, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an, Shandong 271018, P.R. China
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e-mail: qwmeng@sdau.edu.cn

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 (H2O2), superoxide anion radical (O2•−) 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.

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