Liu Haoran, Duan Lingxiao, Tang Chaqin, Ma Jianqiang, Jin Ji-Qiang, Chen Jiedan, He Weizhong, Yao Mingzhe, Chen Liang
Key Laboratory of Biology, Genetics and Breeding of Special Economic Animals and Plants, Ministry of Agriculture and Rural Affairs, Tea Research Institute of the Chinese Academy of Agricultural Sciences, No. 9, Meiling South Road, Hangzhou, Zhejiang 310008, China.
Yunnan Key Laboratory of Tea Germplasm Conservation and Utilization in the Lancang River Basin, West Yunnan University, No. 2, Xuefu Road, Lincang, Yunnan 677000, China.
Hortic Res. 2025 Mar 25;12(7):uhaf098. doi: 10.1093/hr/uhaf098. eCollection 2025 Jul.
Mechanical harvesting in the tea industry has become increasingly essential due to its advantages in increasing productivity and reducing labor costs. Leaf droopiness caused a high rate of broken leaves, hindering the mechanized harvesting quality. However, the underlying mechanisms remain unclear. We herein identified a quantitative trait locus, designated as , along with three lead single nucleotide polymorphisms (SNPs) located near a gene (), named , through performing a genome-wide association study (GWAS) on 130 tea accessions. Integrated analysis of RNA-seq and ATAC-seq confirmed as a droopiness-associated candidate gene at the transcriptional level. was then proved to negatively regulate brassinosteroid-induced droopiness by using the -silencing tea plant. Whole-genome sequencing (WGS) combined with genome walking further indicated that a single-base mutation (T-A) in the promoter of . ChIP-seq revealed that this mutation occurred within the binding site, E-box, of CsBES1.2 on the promoter. Notably, CsBES1.2 bound the E-box of promoter to repress the expression of , as demonstrated by chromatin immunoprecipitation quantitative polymerase chain reaction (ChIP-qPCR), electrophoretic mobility shift assays (EMSA), and transient assays. The single-base mutation strengthened the inhibitory effect of CsBES1.2 on the expression of via enhancing the binding affinity to the E-box. Altogether, our findings suggest that CsTPR negatively regulates droopiness in tea plants under the transcriptional repression of CsBES1.2 and that a single-base mutation within E-box amplifies the suppression of CsBES1.2 on the expression of .
由于机械采摘在提高茶叶产量和降低劳动力成本方面具有优势，因此在茶叶行业中变得越来越重要。叶片下垂导致大量叶片破碎，影响了机械化采摘的质量。然而，其潜在机制尚不清楚。我们通过对130份茶树品种进行全基因组关联研究（GWAS），鉴定出一个数量性状位点，命名为 ，以及位于一个 基因（命名为 ）附近的三个主要单核苷酸多态性（SNP）。RNA-seq和ATAC-seq的综合分析在转录水平上证实 是一个与下垂相关的候选基因。然后，通过使用沉默 的茶树证明 负调控油菜素内酯诱导的下垂。全基因组测序（WGS）结合基因组步移进一步表明， 在启动子区域存在单碱基突变（T-A）。ChIP-seq显示该突变发生在启动子上CsBES1.2的结合位点E-box内。值得注意的是，染色质免疫沉淀定量聚合酶链反应（ChIP-qPCR）、电泳迁移率变动分析（EMSA）和瞬时分析表明，CsBES1.2结合启动子的E-box以抑制 的表达。单碱基突变通过增强与E-box的结合亲和力，增强了CsBES1.2对 表达的抑制作用。总之，我们的研究结果表明，CsTPR在CsBES1.2的转录抑制下负调控茶树的下垂，并且E-box内的单碱基突变放大了CsBES1.2对 表达的抑制作用。
