Terpene synthases in cucumber (Cucumis sativus) and their contribution to herbivore-induced volatile terpenoid emission

背景+问题：Terpenoids play important roles in flavour, pollinator attraction and defence of plants. In cucumber (Cucumis sativus) they are important components of the herbivore-induced plant volatile blend that attracts natural enemies of herbivores. 

主要研究：We annotated the cucumber TERPENE SYNTHASE gene (CsTPS) family and characterized their involvement in the response towards herbivores with different feeding guilds using a combined molecular and biochemical approach. 

结果1-转录水平：Transcripts of multiple CsTPS genes were upregulated in leaves upon herbivory and the products generated by the expressed proteins match the terpenoids recorded in the volatile blend released by herbivore-damaged leaves. 

结果2-诱导表达：Spatial and temporal analysis of the promoter activity of CsTPS genes showed thatcell-content-feeding spider mites (Tetranychus urticae) and thrips (Frankliniella occidentalis) induce promoter activity of CsTPS9 and CsTPS19 within hours after initiation of infestation, while phloem-feeding aphids (Myzus persicae) induced CsTPS2 promoter activity. 

结论：Our findings present detailed insight into the involvement of the TPS gene family in the dynamics and fine-tuning of the emission of herbivore-induced plant volatiles in cucumber, and open a new avenue to understand molecular mechanisms that affect plant-herbivore interactions.

 摘 要 

萜类化合物在植物的风味、吸引传粉者以及防御方面发挥重要作用。在黄瓜中，萜类化合物是植食性昆虫诱导的植物挥发性混合物的重要组成部分，其可以吸引植食性昆虫的天敌。本文中，作者鉴定了黄瓜中的萜类合酶CsTPS基因家族，并鉴定了这些基因在黄瓜响应具有不同进食习性的植食性昆虫中的参与和功能。多个CsTPS基因的转录本在植食性昆虫采食后的叶片中上调表达，并且这些表达的蛋白所产生的产物与植食性昆虫采食后损伤叶片所释放的挥发性混合物中已知的萜类化合物一致。对CsTPS基因启动子活性的时空分析表明，在侵噬开始后数小时内，以细胞内含物为食的叶螨和蓟马会诱导CsTPS9和CsTPS19启动子活性，而主要以韧皮部为食的蚜虫则会诱导CsTPS2的启动子活性。本文的研究结果详细揭示了黄瓜TPS基因家族在植食性昆虫诱导的植物挥发物释放的动态和精细调控中的作用，并为理解影响植物-植食性昆虫之间相互作用的分子机制开辟了一条新途径。