Wang Yong-Xin, Teng Rui-Min, Wang Wen-Li, Wang Ying, Shen Wei, Zhuang Jing
Tea Science Research Institute, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.
Protoplasma. 2019 Mar;256(2):359-370. doi: 10.1007/s00709-018-1299-9. Epub 2018 Aug 18.
Lignin is a complex aromatic heteropolymer that plays essential roles in mechanical support, water transport, and response to biotic and abiotic stresses. The tea plant is a leaf-type beverage crop, which serves as a resource for non-alcoholic beverage tea. The content and distribution of lignin in tea plant leaves seriously affect the quality of tea. However, the biosynthetic pathways of lignin remain to be characterized in the tea plant. In the present study, lignin accumulation was investigated in tea plant leaves and stems at three developmental stages. The lignin content continuously increased during leaf and stem development in both tea plant cultivars 'Fudingdabai' and 'Suchazao.' The lignin distribution and anatomical characteristics of the tea plant leaves coincided with lignin accumulation and showed that lignin is mainly distributed in the epidermis, xylem, and vascular bundle sheath. 'Suchazao' exhibits a low lignin content and lacks a vascular bundle sheath. Twelve genes encoding the enzymes involved in the lignin biosynthesis of tea plant were identified and included CsPAL, CsC4H, Cs4CL, CsHCT, CsC3H, CsCCoAOMT, CsCCR, CsCAD, CsF5H, CsCOMT, CsPER, and CsLAC. The expression profiling of lignin biosynthesis-related genes and analysis of lignin accumulation may help elaborate the regulatory mechanisms of lignin biosynthesis in tea plant.
木质素是一种复杂的芳香族杂聚物，在机械支撑、水分运输以及对生物和非生物胁迫的响应中发挥着重要作用。茶树是一种叶用饮料作物，是生产非酒精饮料茶的资源。茶树叶片中木质素的含量和分布严重影响茶叶品质。然而，茶树中木质素的生物合成途径仍有待阐明。在本研究中，对茶树叶片和茎在三个发育阶段的木质素积累进行了研究。在茶树品种‘福鼎大白’和‘舒茶早’的叶片和茎发育过程中，木质素含量持续增加。茶树叶片的木质素分布和解剖特征与木质素积累情况相符，表明木质素主要分布在表皮、木质部和维管束鞘中。‘舒茶早’的木质素含量较低且缺乏维管束鞘。鉴定出了12个编码参与茶树木质素生物合成的酶的基因，包括CsPAL、CsC4H、Cs4CL、CsHCT、CsC3H、CsCCoAOMT、CsCCR、CsCAD、CsF5H、CsCOMT、CsPER和CsLAC。木质素生物合成相关基因的表达谱分析和木质素积累分析可能有助于阐明茶树中木质素生物合成的调控机制。
