Tea Research Institute, Qingdao Agricultural University, Qingdao, Shandong 266109, China.
Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China.
J Plant Physiol. 2017 Dec;219:91-99. doi: 10.1016/j.jplph.2017.10.001. Epub 2017 Oct 20.
Drought is a crucial limiting factor for tea yield and quality. To systematically characterize the molecular response of tea plants to drought stress and its capacity to recover, we used iTRAQ-based comparative proteomic approach to investigate the effects of drought on protein expression profiles in tea seedlings subjected to different drought treatments. A total of 3274 proteins were identified, of which 2169 and 2300 showed differential expressions during drought and recovery, respectively. Functional annotation showed that multiple biological processes were regulated, suggesting that tea plants probably employed multiple and synergistic resistance mechanisms in dealing with drought stress. Hierarchical clustering showed that chlorophyll a/b-binding proteins were up-regulated in DB and RE, suggesting that tea plants might regulate expression of chlorophyll a/b-binding proteins to maintain the photosystem II function during drought stress. Abundant proteins involved in sulfur-containing metabolite pathways, such as glutathione, taurine, hypotaurine, methionine, and cysteine, changed significantly during drought stress. Among them, TL29 interacted with LHCb6 to connect S-containing metabolites with chlorophyll a/b-binding proteins. This suggests that sulfur-containing compounds play important roles in the response to drought stress in tea plants. In addition, the expression of PAL was up-regulated in DA and down-regulated in DB. Cinnamyl alcohol dehydrogenase, caffeic acid O-methyltransferase, and 4-coumarate-CoA ligase also showed significant changes in expression levels, which regulated the biosynthesis of polyphenols. The results indicate that slight drought stress might promote polyphenol biosynthesis, while serious drought stress leads to inhibition. The expression of lipoxygenase and short-chain dehydrogenase increased during slight drought stress and some volatile metabolite pathways were enriched, indicating that drought stress might affect the tea aroma. The study provides valuable information that will lay the foundation for studies investigating the functions of drought response genes in tea leaves.
干旱是影响茶叶产量和品质的关键限制因素。为了系统地描述茶树对干旱胁迫的分子响应及其恢复能力，我们采用 iTRAQ 基于比较蛋白质组学方法研究了干旱对不同干旱处理下茶树幼苗蛋白质表达谱的影响。共鉴定到 3274 种蛋白质，其中 2169 种和 2300 种在干旱和恢复过程中分别表现出差异表达。功能注释表明，多个生物学过程受到调控，表明茶树可能采用多种协同的抗性机制来应对干旱胁迫。层次聚类表明，叶绿素 a/b 结合蛋白在 DB 和 RE 中上调，表明茶树可能通过调节叶绿素 a/b 结合蛋白的表达来维持干旱胁迫下的光系统 II 功能。大量参与含硫代谢物途径的蛋白质，如谷胱甘肽、牛磺酸、次牛磺酸、蛋氨酸和半胱氨酸，在干旱胁迫过程中变化显著。其中，TL29 与 LHCb6 相互作用，将含硫代谢物与叶绿素 a/b 结合蛋白连接起来。这表明含硫化合物在茶树应对干旱胁迫中发挥重要作用。此外，PAL 的表达在 DA 中上调，在 DB 中下调。肉桂醇脱氢酶、咖啡酸 O-甲基转移酶和 4-香豆酸辅酶 A 连接酶的表达水平也发生了显著变化，调控了多酚的生物合成。结果表明，轻度干旱胁迫可能促进多酚的生物合成，而严重干旱胁迫则导致抑制。在轻度干旱胁迫下，脂氧合酶和短链脱氢酶的表达增加，一些挥发性代谢物途径被富集，表明干旱胁迫可能影响茶叶香气。该研究提供了有价值的信息，为研究干旱响应基因在茶叶中的功能奠定了基础。
