title: Positive feedback regulation of a Lycium chinense-derived VDE gene by drought-induced endogenous ABA, and over-expression of this VDE gene improve drought-induced photo-damage in Arabidopsis.
abstract: Violaxanthin de-epoxidase (VDE) plays an important role in protecting the photosynthetic apparatus from photo-damage by dissipating excessively absorbed light energy as heat, via the conversion of violaxanthin (V) to intermediate product antheraxanthin (A) and final product zeaxanthin (Z) under light stress. We have cloned a VDE gene (LcVDE) from Lycium chinense, a deciduous woody perennial halophyte, which can grow in a large variety of soil types. The amino acid sequence of LcVDE has high homology with VDEs in other plants. Under drought stress, relative expression of LcVDE and the de-epoxidation ratio (Z+0.5A)/(V+A+Z) increased rapidly, and non-photochemical quenching (NPQ) also rose. Interestingly, these elevations induced by drought stress were reduced by the topical administration of abamine SG, a potent ABA inhibitor via inhibition of NCED in the ABA synthesis pathway. Until now, little has been done to explore the relationship between endogenous ABA and the expression of VDE genes. Since V serves as a common precursor for ABA, these data support the possible involvement of endogenous ABA in the positive feedback regulation of LcVDE gene expression in L. chinense under drought stress. Moreover, the LcVDE may be involved in modulating the level of photosynthesis damage caused by drought stress. Furthermore, the ratio of (Z+0.5A)/(V+A+Z) and NPQ increased more in transgenic Arabidopsis over-expressing LcVDE gene than the wild types under drought stress. The maximum quantum yield of primary photochemistry of PSII (Fv/Fm) in transgenic Arabidopsis decreased more slowly during the stressed period than that in wild types under the same conditions. Furthermore, transgenic Arabidopsis over-expressing LcVDE showed increased tolerance to drought stress.
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, People's Republic of China.
authors.forename: Chunfeng
authors.initials: C
authors.lastname: Guan
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, People's Republic of China. Electronic address: jijing@tju.edu.cn.
authors.forename: Jing
authors.initials: J
authors.lastname: Ji
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, People's Republic of China.
authors.forename: Xuqiang
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Medical Genetics, Tianjin Medical University General Hospital, Tianjin 300072, People's Republic of China.
authors.forename: Xiaozhou
authors.initials: X
authors.lastname: Li
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, People's Republic of China.
authors.forename: Chao
authors.initials: C
authors.lastname: Jin
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China.
authors.forename: Wenzhu
authors.initials: W
authors.lastname: Guan
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, People's Republic of China. Electronic address: gangwang@tju.edu.cn.
authors.forename: Gang
authors.initials: G
authors.lastname: Wang
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D001483:Base Sequence; D055864:Droughts; D025461:Feedback, Physiological; D018506:Gene Expression Regulation, Plant; D008027:Light; D032305:Lycium / Q000201:enzymology / Q000235:genetics*; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D010788:Photosynthesis / Q000502:physiology; D045332:Photosystem II Protein Complex / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013312:Stress, Physiological; D024341:Xanthophylls / Q000378:metabolism
chemical_list: D045332:Photosystem II Protein Complex; D010937:Plant Growth Regulators; D010940:Plant Proteins; D024341:Xanthophylls; C031140:antheraxanthin; C005613:violaxanthin; D000040:Abscisic Acid; D010088:Oxidoreductases; C023290:violaxanthin de-epoxidase
keywords: Drought stress; Endogenous ABA; L. chinense; Photochemical quenching; VDE