Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology/Laboratory of Fruit Quality Biology, Zhejiang University, Hangzhou 310058, China.
Zhejiang Agricultural Technology Extension Center, Hangzhou 310029, China.
Molecules. 2019 Jul 15;24(14):2564. doi: 10.3390/molecules24142564.
Finger citron ( var. ) is a popular ornamental tree and an important source of essential oils rich in terpenoids, but the mechanisms behind volatile formation are poorly understood. We investigated gene expression changes combined with volatile profiling of ten samples from three developing organs: flower, leaf, and fruit. A total of 62 volatiles were identified with limonene and γ-terpinene being the most abundant ones. Six volatiles were identified using partial least squares discriminant analysis (PLS-DA) that could be used as markers for distinguishing finger citron from other citrus species. RNA-Seq revealed 1,611,966,118 high quality clean reads that were assembled into 32,579 unigenes. From these a total of 58 terpene synthase (TPS) gene family members were identified and the spatial and temporal distribution of their transcripts was measured in developing organs. Transcript levels of transcription factor genes (251), (169), (76), (155), (184), and (66) during finger citron development were also analyzed. From extracted subnetworks of three modules constructed by weighted gene co-expression network analysis (WGCNA), thirteen genes and fifteen transcription factors were suggested to be related to volatile terpenoid formation. These results provide a framework for future investigations into the identification and regulatory network of terpenoids in finger citron.
佛手（变种）是一种受欢迎的观赏树种，也是富含萜类化合物的重要精油来源，但挥发性形成的机制仍知之甚少。我们通过对来自三个发育器官（花、叶和果实）的十个样本进行基因表达变化结合挥发性成分分析，进行了研究。共鉴定出 62 种挥发物，其中柠檬烯和γ-萜品烯含量最丰富。使用偏最小二乘判别分析（PLS-DA）鉴定出 6 种可用于区分佛手与其他柑橘属物种的挥发性物质作为标志物。RNA-Seq 共获得 1611966118 条高质量清洁reads，组装成 32579 条unigenes。从中总共鉴定出 58 个萜烯合酶（TPS）基因家族成员，并测量了它们在发育器官中的转录时空分布。还分析了佛手发育过程中转录因子基因（251）、（169）、（76）、（155）、（184）和（66）的转录水平。通过加权基因共表达网络分析（WGCNA）构建的三个模块的提取子网络，提出了 13 个基因和 15 个转录因子与挥发性萜类化合物的形成有关。这些结果为进一步研究佛手萜类化合物的鉴定和调控网络提供了框架。
