Lathyrus odoratus (sweet pea) is an ornamental plant with exceptional floral scent, previously used as an experimental organism in the early development of Mendelian genetics. However, its terpene synthases (TPS), which act as metabolic gatekeepers in the biosynthesis of volatile terpenoids, remain to be characterized. Auto-Headspace Solid-phase Microextraction/GC-MS analysis of floral volatile terpene constituents from seven sweet pea cultivars identified α-bergamotene, linalool, (-)-α-cubebene, geraniol, β-caryophyllene and β-sesquiphellandrene as the dominant compounds. RNA sequencing was performed to profile the transcriptome of Lathyrus odoratus flowers. Bioinformatic analysis identified eight TPS genes (acronymed as LoTPS) that were successfully cloned, heterologously expressed and functionally analyzed. LoTPS4 and LoTPS7, belonging to the TPS-b clade, biochemically catalyzed the formation of monoterpenes and sesquiterpenes. LoTPS3 and LoTPS8, placed in the TPS-a clade, also generated monoterpenes and sesquiterpenes, while LoTPS12 belonging to the TPS-g clade showed linalool/nerolidol synthase activity. Notably, biochemical assays of the recombinant LoTPS proteins revealed their catalytic promiscuity, and the enzymatic products were basically consistent with major volatile compounds released from sweet pea flowers. The data from our study lay the foundation for the chemical ecology, molecular genetics and biotechnological improvement of sweet pea and other legumes (Fabaceae).

中文翻译：

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萜烯合酶的功能表征，解释了山thy豆栽培品种中挥发萜的异质性。

山thy豆（香豌豆）是一种具有特殊花香的观赏植物，以前曾在孟德尔遗传学的早期发展中用作实验生物。然而，其萜烯合酶（TPS）在挥发性萜类化合物的生物合成中充当代谢的守门员，仍有待表征。自动顶空固相微萃取/ GC-MS分析来自七个甜豌豆品种的花卉挥发性萜烯成分，确定了α-香柠檬烯，芳樟醇，（-）-α-立方丁香，香叶醇，β-石竹烯和β-倍半萜烯为主要成分。进行RNA测序以分析山thy豆花的转录组。生物信息学分析确定了8个TPS基因（简称LoTPS）），成功克隆，异源表达和功能分析。属于TPS- b进化枝的LoTPS4和LoTPS7生化催化了单萜和倍半萜的形成。LoTPS3和LoTPS8，放置在TPS-一个进化枝，也产生单萜和倍半萜烯，而LoTPS12属于TPS-克进化枝表明芳樟醇/橙花叔醇合酶活性。值得注意的是，重组LoTPS蛋白的生化分析显示了它们的催化混杂性，并且酶促产物与从豌豆花中释放的主要挥发性化合物基本一致。我们研究的数据为香豌豆和其他豆类（豆科）的化学生态学，分子遗传学和生物技术改进奠定了基础。