Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing 100193, China.
Agricultural and Rural Bureau of Qingxian in Hebei Province, Qingxian 062650, China.
Plant Physiol. 2023 Aug 3;192(4):2723-2736. doi: 10.1093/plphys/kiad236.
Glandular trichomes (GTs) are outgrowths of plant epidermal cells that secrete and store specialized secondary metabolites that protect plants against biotic and abiotic stresses and have economic importance for human use. While extensive work has been done to understand the molecular mechanisms of trichome organogenesis in Arabidopsis (Arabidopsis thaliana), which forms unicellular, nonglandular trichomes (NGTs), little is known about the mechanisms of GT development or regulation of secondary metabolites in plants with multicellular GTs. Here, we identified and functionally characterized genes associated with GT organogenesis and secondary metabolism in GTs of cucumber (Cucumis sativus). We developed a method for effective separation and isolation of cucumber GTs and NGTs. Transcriptomic and metabolomic analyses showed that flavonoid accumulation in cucumber GTs is positively associated with increased expression of related biosynthesis genes. We identified 67 GT development-related genes, the functions of 7 of which were validated by virus-induced gene silencing. We further validated the role of cucumber ECERIFERUM1 (CsCER1) in GT organogenesis by overexpression and RNA interference transgenic approaches. We further show that the transcription factor TINY BRANCHED HAIR (CsTBH) serves as a central regulator of flavonoid biosynthesis in cucumber GTs. Work from this study provides insight into the development of secondary metabolite biosynthesis in multicellular GTs.
腺毛（GTs）是植物表皮细胞的突起，能够分泌和储存专门的次生代谢产物，这些产物可以保护植物免受生物和非生物胁迫的影响，并且对人类的利用具有经济重要性。虽然已经进行了广泛的研究来理解拟南芥（Arabidopsis thaliana）中单细胞非腺毛（NGTs）的毛状体发生的分子机制，但对于多细胞 GTs 中 GT 发育或次生代谢物调控的机制知之甚少。在这里，我们鉴定并功能表征了与黄瓜（Cucumis sativus）GTs 中的 GT 器官发生和次生代谢相关的基因。我们开发了一种有效分离黄瓜 GTs 和 NGTs 的方法。转录组和代谢组学分析表明，黄瓜 GTs 中类黄酮的积累与相关生物合成基因的表达增加呈正相关。我们鉴定了 67 个与 GT 发育相关的基因，其中 7 个基因的功能通过病毒诱导的基因沉默得到了验证。我们进一步通过过表达和 RNA 干扰转基因方法验证了黄瓜 ECERIFERUM1（CsCER1）在 GT 器官发生中的作用。我们进一步表明，转录因子 TINY BRANCHED HAIR（CsTBH）作为黄瓜 GTs 中类黄酮生物合成的中央调控因子。这项研究的工作为多细胞 GTs 中次生代谢物生物合成的发展提供了深入的了解。
