As a volatile hormone signal, methyl jasmonate (MeJA) can regulate the biosynthesis of secondary metabolites. But in floral fragrance, the effect and mechanisms of MeJA on monoterpenes, the major components of many plants, are largely unknown. In this paper, we measured the release of monoterpenes from petals of Lilium ‘Siberia’ after MeJA treatment, as well as the expressions of monoterpene pathway genes and Lilium coronatine-insensitive (LiCOI1) gene. Then the LiCOI1 gene was cloned, and using virus-induced gene silencing (VIGS) technology, its function in monoterpene biosynthesis in response to MeJA was validated. The results showed that MeJA significantly improved the release amounts of myrcene, ocimene, and linalool. The expression levels of synthase genes [Lilium myrcene synthase (LiMYS), Lilium ocimene synthase (LiOCS), as well as Lilium linalool synthase (LiLIS)], two pathway genes [Lilium 1-deoxy-D-xylulose 5-phosphate synthase (LiDXS) and Lilium 1-deoxy-D-xylulose-5-phosphate reductoisomerase (LiDXR)] were enhanced. Moreover, the LiCOI1 gene exhibited a remarkably increased expression level, which suggested its signaling role. Based on the analysis, the full length of LiCOI1 gene was 1809 bp, whose deduced protein contained 602 amino acids and was mainly located in the nucleus. Silencing the expression of LiCOI1 in petals significantly depressed not only the gene expressions of LiMYS, LiOCS, LiLIS, LiDXS, and LiDXR, but also the release amounts of myrcene, ocimene, and linalool. These results confirm that LiCOI1 plays an important signaling role in MeJA-induced enhancement of monoterpene biosynthesis in Lilium ‘Siberia’.

作为一种挥发性激素信号，茉莉酸甲酯（MeJA）可以调节次级代谢产物的生物合成。但在花香中，MeJA 对单萜（许多植物的主要成分）的作用和机制尚不清楚。在本文中，我们测量了MeJA处理后‘西伯利亚’百合花瓣中单萜的释放量，以及单萜途径基因和百合冠菌素不敏感( LiCOI1 )基因的表达。然后克隆了LiCOI1基因，并利用病毒诱导基因沉默（VIGS）技术，验证了其在响应MeJA的单萜生物合成中的功能。结果表明，MeJA 显着提高了月桂烯、罗勒烯和芳樟醇的释放量。合酶基因 [百合月桂烯合酶( LiMYS )、百合罗勒烯合酶( LiOCS ) 以及百合芳樟醇合酶( LiLIS )]、两个途径基因 [百合1-脱氧-D-木酮糖 5-磷酸合酶( LiDXS ) 的表达水平) 和百合1-脱氧-D-木酮糖-5-磷酸还原异构酶( LiDXR )] 得到增强。此外，LiCOI1基因的表达水平显着增加，这表明其信号作用。经分析，LiCOI1基因全长1809 bp，推导蛋白含602个氨基酸，主要定位于细胞核。沉默花瓣中LiCOI1的表达不仅显着降低了LiMYS、LiOCS、LiLIS、LiDXS和LiDXR的基因表达，而且显着降低了月桂烯、罗勒烯和芳樟醇的释放量。这些结果证实 LiCOI1 在 MeJA 诱导的西伯利亚百合单萜生物合成增强中发挥重要的信号作用。