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.

遮荫可以有效减少光抑制作用并提高茶的质量。木质素是最重要的次生代谢产物之一，在植物的生长发育中起着至关重要的作用。然而，关于茶树的遮光和木糖异生之间的关系知之甚少。为了研究遮光对茶树木质素积累的影响，对“龙井43号”分别进行了不遮光（S0），40％（S1）和80％（S2）遮光处理。在遮光处理下（尤其是S2），茶树叶片的叶面积和木质素含量降低。解剖特征表明，木质素主要分布在茶叶的木质部中。启动子分析表明，木质素途径中涉及的基因含有几种光识别元件。12种木质素相关基因的转录丰度在遮光处理下发生了变化。相关分析表明，大多数基因与木质素含量呈强正相关，而在40％和80％遮光处理下，CsPAL，Cs4CL，CsF5H和CsLAC表现出显着的正相关。结果表明，遮光可能对茶叶中木质素的积累有重要影响。这项工作可能有助于了解遮光处理下木质素途径的调控机制，并为在野外作业中通过遮光处理降低木质素含量和改善茶叶质量提供参考。