Transcriptome Analysis of Oleoresin-Producing Tree Sindora glabra and Characterization of Sesquiterpene Synthases
Transcriptome Analysis of Oleoresin-Producing Tree Sindora glabra and Characterization of Sesquiterpene Synthases
复制标题
油树脂生产树 Sindora Glabra 的转录组分析和倍半萜烯合成酶的表征
DOI：
10.3389/fpls.2018.01619
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发表时间：
2018
影响因子：
5.6
通讯作者：
Rong-Shen
中科院分区：
文献类型：
--
作者：
Niu Yu;Jin-Chang Yang;Guang-Tian Yin;Rong-Shen
萜类化合物在植物中具有重要的生理和生态功能。光叶番荔枝茎中积累了大量富含倍半萜的油树脂。利用转录组方法确定了独特的萜类生物合成途径，并探索了导致萜类含量个体差异的不同调控机制。对重新组装的重叠群的分析揭示了一套完整的萜类生物合成基因。在高产和低产植物之间共发现了23261个差异表达的Uniges(Deg)。DG富集度分析表明，萜类的生物合成过程和植物激素信号转导途径可能在决定光肩星天萜的变异中发挥重要作用。通过定量RT-PCR实验进一步验证了候选基因的表达模式。参与萜类生物合成途径的关键基因主要在韧皮部和根组织中表达。系统发育分析和亚细胞定位表明，光皮菌萜烯合酶可能是从一个共同的祖先进化而来的。此外，还对两个倍半萜合成酶基因SgSTPS1和SgSTPS2进行了功能分析。SgSTPS1主要由金合欢基焦磷酸合成b-石竹烯。SgSTPS2是一种多用途的酶，它催化由焦磷酸法尼基生成12个顺丁烯，以及利用焦磷酸香叶基合成3个单萜烯。这些结果为阐明光肩星天萜生物合成的分子机制和探索倍半萜的生态功能提供了巨大的储备库。
Terpenes serve important physiological and ecological functions in plants. Sindora glabra trees accumulate copious amounts of sesquiterpene-rich oleoresin in the stem.A transcriptome approach was used to determine the unique terpene biosynthesis pathway and to explore the different regulatory mechanisms responsible for the variation of terpene content among individuals. Analysis of de novo-assembled contigs revealed a complete set of genes for terpene biosynthesis. A total of 23,261 differentially expressed unigenes (DEGs) were discovered between high and low oil-yielding plants. DEG enrichment analysis suggested that the terpene biosynthesis process and the plant hormone signal transduction pathway may exert a major role in determining terpene variation in S. glabra. The expression patterns of candidate genes were further verified by quantitative RT-PCR experiments. Key genes involved in the terpene biosynthesis pathway were predominantly expressed in phloem and root tissues. Phylogenetic analysis and subcellular localization implied that S. glabra terpene synthases may evolve from a common ancestor. Furthermore, two sesquiterpene synthase genes, SgSTPS1 and SgSTPS2, were functionally characterized. SgSTPS1 mainly generated b-caryophyllene from farnesyl pyrophosphate. SgSTPS2 is a versatile enzyme that catalyzes the formation of 12 sequiterpenes from farnesyl pyrophosphate and synthesis of three monoterpenes using geranyl pyrophosphate. Together, these results provide large reservoir for elucidating the molecular mechanism of terpene biosynthesis and for exploring the ecological function of sesquiterpenes in S. glabra.