Liu Xuesong, Xu Yinghao, Zhang Yujun, Chen Xiaofei, Li Pengxia
Institute of Agricultural Facilities and Equipment, Jiangsu Academy of Agricultural Sciences, 50 Zhongling Road, Nanjing 210014, Jiangsu, China.
Department of Food Science, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110043, China.
Hortic Res. 2025 Jan 6;12(4):uhaf004. doi: 10.1093/hr/uhaf004. eCollection 2025 Apr.
Brassinosteroids (BRs) are extensively distributed in plants and play crucial roles throughout all stages of plant growth. Nevertheless, the molecular mechanism through which BRs influence postharvest senescence in pakchoi remains elusive. Previous studies have demonstrated that the application of 1.5 μM of the BRs analog 2,4-epibrassinolide (EBR) delayed the leaf senescence in harvested pakchoi. In this study, we constructed the EBR-delayed senescence transcriptome in pakchoi leaves and discovered that EBR modulates the expression of genes involved in the chlorophyll (Chl) metabolism pathway and the BRs pathway in pakchoi. Notably, we identified and characterized an EBR-suppressed, nucleus-localized WRKY transcription factor called . is a highly expressed transcriptional activator in senescent leaves, targeting the promoters of the Chl degradation-associated gene and the BRs degradation-associated gene , thereby promoting their expression. Overexpression of the gene accelerated the senescence process in leaves, while EBR treatment mitigated the leaf senescence phenotype induced by overexpression. Conversely, silencing of through the virus-induced gene silencing extended the postharvest storage period of pakchoi. In conclusion, the newly discovered BRs- regulatory model in this study provides novel insights into BRs-mediated leaf senescence in pakchoi.
油菜素类固醇（BRs）广泛分布于植物中，并在植物生长的各个阶段发挥关键作用。然而，BRs影响小白菜采后衰老的分子机制仍不清楚。先前的研究表明，施用1.5 μM的BRs类似物2,4-表油菜素内酯（EBR）可延缓采收后小白菜叶片的衰老。在本研究中，我们构建了EBR延缓衰老的小白菜叶片转录组，并发现EBR调节小白菜中参与叶绿素（Chl）代谢途径和BRs途径的基因表达。值得注意的是，我们鉴定并表征了一种EBR抑制的、定位于细胞核的WRKY转录因子，称为 。 在衰老叶片中是一种高表达的转录激活因子，靶向叶绿素降解相关基因 和BRs降解相关基因 的启动子，从而促进它们的表达。 基因的过表达加速了 叶片的衰老过程，而EBR处理减轻了由 过表达诱导的叶片衰老表型。相反，通过病毒诱导基因沉默对 进行沉默延长了小白菜的采后贮藏期。总之，本研究新发现的BRs调控模型为BRs介导的小白菜叶片衰老提供了新的见解。
