Yu Shuwei, Li Penghui, Zhao Xuecheng, Tan Mangmang, Ahmad Muhammad Zulfiqar, Xu Yujie, Tadege Million, Zhao Jian
State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, 230036, China.
Department of Plant and Soil Sciences, Institute for Agricultural Biosciences, Oklahoma State University, 3210 Sam Noble Parkway, Ardmore, OK, 73401, USA.
Hortic Res. 2021 May 1;8(1):104. doi: 10.1038/s41438-021-00538-7.
The growth of leaves and biosynthesis of characteristic secondary metabolites are critically important for tea production and quality control. However, little is known about the coordinated regulation of leaf development and catechin biosynthesis in tea plants. Here, we reported that TCP TFs are involved in both catechin biosynthesis and leaf development. An integrated analysis of catechin profiling and CsTCP expression in different tissues of plants under various environmental conditions at different developmental stages indicated significant correlations between the transcript levels of CIN-type TCPs and catechin production. CIN-type CsTCP3 and CsTCP4 and PCF-type CsTCP14 interacted with the MYB-bHLH-WD40 repeat (MBW) complex by forming a CsTCP3-CsTT8 heterodimer and modulating the transactivation activity of the promoters of anthocyanin synthase (CsANS1) and anthocyanidin reductase (CsANR1). Four types of microRNA/target modules, miR319b/CsTCP3-4, miR164b/CsCUC, miR396/CsGRF-GIF, and miR165b/HD-ZIPIII ones, were also identified and characterized for their functions in the regulation of the development of tea plant shoot tips and leaf shape. The results of these modules were reflected by their different expression patterns in developing buds and leaves that had distinctly different morphologies in three different tea plant varieties. Their roles in the regulation of catechin biosynthesis were also further verified by manipulation of microRNA319b (miR319b), which targets the transcripts of CsTCP3 and CsTCP4. Thus, CsTCPs represent at least one of these important groups of TFs that can integrate tea plant leaf development together with secondary metabolite biosynthesis. Our study provides new insight into shoot tip development and catechin production in tea plants and lays a foundation for further mechanistic understanding of the regulation of tea plant leaf development and secondary metabolism.
叶片生长和特征性次生代谢产物的生物合成对于茶叶生产和质量控制至关重要。然而，关于茶树叶片发育和儿茶素生物合成的协同调控知之甚少。在此，我们报道TCP转录因子参与儿茶素生物合成和叶片发育。对不同发育阶段各种环境条件下植物不同组织中的儿茶素谱和CsTCP表达进行综合分析表明，CIN型TCP的转录水平与儿茶素产生之间存在显著相关性。CIN型CsTCP3和CsTCP4以及PCF型CsTCP14通过形成CsTCP3-CsTT8异二聚体并调节花青素合酶（CsANS1）和花青素还原酶（CsANR1）启动子的反式激活活性，与MYB-bHLH-WD40重复（MBW）复合体相互作用。还鉴定并表征了四种类型的microRNA/靶标模块，即miR319b/CsTCP3-4、miR164b/CsCUC、miR396/CsGRF-GIF和miR165b/HD-ZIPIII模块，它们在调控茶树茎尖发育和叶片形状方面的功能。这些模块的结果通过它们在三个不同茶树品种中形态明显不同的发育芽和叶片中的不同表达模式得以体现。通过操纵靶向CsTCP3和CsTCP4转录本的microRNA319b（miR319b），进一步验证了它们在儿茶素生物合成调控中的作用。因此，CsTCPs代表了至少一组重要的转录因子，它们可以将茶树叶片发育与次生代谢产物生物合成整合在一起。我们的研究为茶树茎尖发育和儿茶素产生提供了新的见解，并为进一步从机制上理解茶树叶片发育和次生代谢调控奠定了基础。
