Tea Science Research Institute, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.
Mol Genet Genomics. 2021 Jan;296(1):165-177. doi: 10.1007/s00438-020-01737-y. Epub 2020 Oct 28.
Shading can effectively reduce photoinhibition and improve the quality of tea. Lignin is one of the most important secondary metabolites that play vital functions in plant growth and development. However, little is known about the relationship between shading and xylogenesis in tea plant. To investigate the effects of shading on lignin accumulation in tea plants, 'Longjing 43' was treated with no shading (S0), 40% (S1) and 80% (S2) shading treatments, respectively. The leaf area and lignin content of tea plant leaves decreased under shading treatments (especially S2). The anatomical characteristics showed that lignin is mainly distributed in the xylem of tea leaves. Promoter analysis indicated that the genes involved in lignin pathway contain several light recognition elements. The transcript abundances of 12 lignin-associated genes were altered under shading treatments. Correlation analysis indicated that most genes showed strong positive correlation with lignin content, and CsPAL, Cs4CL, CsF5H, and CsLAC exhibited significant positively correlation under 40% and 80% shading treatments. The results showed that shading may have an important effect on lignin accumulation in tea leaves. This work will potentially helpful to understand the regulation mechanism of lignin pathway under shading treatment, and provide reference for reducing lignin content and improving tea quality through shading treatment in field operation.
遮荫可以有效降低光抑制，提高茶叶品质。木质素是植物生长发育过程中最重要的次生代谢产物之一，具有重要的功能。然而，关于遮荫与茶树木质素形成之间的关系知之甚少。为了研究遮荫对茶树木质素积累的影响，分别用不遮荫（S0）、40%遮荫（S1）和 80%遮荫（S2）处理龙井 43 茶树。遮荫处理下，茶树叶片的叶面积和木质素含量下降（尤其是 S2）。解剖学特征表明，木质素主要分布在茶树叶片的木质部中。启动子分析表明，木质素途径相关基因含有几个光识别元件。12 个木质素相关基因的转录丰度在遮荫处理下发生改变。相关性分析表明，大多数基因与木质素含量呈强正相关，CsPAL、Cs4CL、CsF5H 和 CsLAC 在 40%和 80%遮荫处理下表现出显著的正相关性。结果表明，遮荫可能对茶树叶片木质素积累有重要影响。这项工作有助于理解遮荫处理下木质素途径的调控机制，并为通过田间操作遮荫处理降低木质素含量和提高茶叶品质提供参考。
