Transcriptomic studies in resistant and susceptible tea cultivars have been performed to reveal the different defense molecular mechanisms of tea after E. onukii feeding. The molecular mechanism by which tea plants respond to small green leafhopper Empoasca onukii (Matsuda) damage is unclear. Using the resistant tea plant cultivar Juyan (JY) and the susceptible tea plant cultivar Enbiao (EB) as materials, this study performed RNA-seq on tea leaf samples collected at three time points (6 h, 12 h, 24 h) during exposure of the plants to leafhopper to reveal the molecular mechanisms that are activated in susceptible and resistant tea plant cultivars in response to leafhopper damage. The numbers of DEGs in the susceptible tea cultivar during early (6 h) and late (24 h) stages of leafhopper induction were higher than those in the resistant cultivar at the same time points. The stress responses to leafhopper were most intense at 12 h in both tea cultivars. Pathway enrichment analysis showed that most up-regulated DEGs and their related metabolic pathways were similar in the two tea cultivars. However, during the early stage of leafhopper induction (6 h), jasmonic acid (JA)-related genes were significantly up-regulated in the resistant cultivar. The terpenoid biosynthetic pathway and the α-linolenic acid metabolic pathway were activated earlier in the resistant cultivar and remained activated until the late stage of leafhopper damage. Our results confirmed that after leafhopper damage, the resistant tea cultivar activated its defense responses earlier than the susceptible cultivar, and these defense responses were mainly related to terpenoid metabolism and JA biosynthetic pathway. The results provide important clues for further studies on resistance strategy of tea plants to pest.

中文翻译：

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抗性和易感茶品种对Empoasca onukii（Matsuda）损害的比较转录组分析

已经对抗性和易感茶品种进行转录组学研究，以揭示茶在 E. onukii 喂养后的不同防御分子机制。茶树响应小绿叶蝉Empoasca onukii (Matsuda) 损害的分子机制尚不清楚。本研究以抗性茶树品种巨燕（JY）和易感茶树品种恩彪（EB）为材料，对暴露期间三个时间点（6 h、12 h、24 h）采集的茶叶样品进行RNA-seq将植物与叶蝉进行比较，以揭示在易感和抗性茶树品种中响应叶蝉损害而被激活的分子机制。叶蝉诱导早期（6 h）和后期（24 h）感病品种的DEGs数量均高于同一时间点的抗病品种。两种茶树对叶蝉的胁迫反应在 12 h 时最为强烈。通路富集分析表明，大多数上调的 DEGs 及其相关代谢通路在两个茶品种中是相似的。然而，在叶蝉诱导的早期（6小时），茉莉酸（JA）相关基因在抗性品种中显着上调。萜类生物合成途径和α-亚麻酸代谢途径在抗病品种中较早被激活，并一直保持激活到叶蝉为害后期。我们的研究结果证实，在叶蝉受损后，抗性茶树品种较易感品种更早地激活其防御反应，这些防御反应主要与萜类代谢和JA生物合成途径有关。研究结果为进一步研究茶树抗病虫害策略提供了重要线索。