Terpenoids are the main components contributing to the fragrance of Lilium ‘Siberia’, and LiTPS2 plays a critical role in the biosynthesis of monoterpenoids. Although the major terpene synthases in Lilium ‘Siberia’ have been identified, how these TPS genes are transcriptionally regulated remains elusive in this distinguished flower. This study aimed to identify transcription factors that regulate the terpene synthesis in Lilium, and disclose the related underlying transcriptional regulation mechanism. In this study, we identified three R2R3-MYB TFs—LiMYB1, LiMYB305 and LiMYB330, which were involved in regulating the biosynthesis of terpenes in Lilium ‘Siberia’. Quantitative real-time PCR showed spatial and temporal expression patterns consistent with the emission patterns of terpene compounds. When LiMYB1, LiMYB305 and LiMYB330 were overexpressed in flowers, the release of some main monoterpenes, such as linalool and ocimene, as well as the expression of TPS genes, especially for LiTPS2, were enhanced. A virus-induced gene silencing (VIGS) assay showed that silencing these three LiMYBs decreased the level of monoterpenes by down-regulating the expression of the TPS genes. The yeast one-hybrid and transient expression assays indicated that all three LiMYBs could bind to and activate the promoter of LiTPS2. Moreover, the yeast two-hybrid assay verified that LiMYB1 could interact with LiMYB308 and LiMYB330, indicating their synergistic roles in the regulation of floral terpene biosynthesis. In general, these results indicated that LiMYB1, LiMYB305, and LiMYB330 might play essential roles in terpene biosynthesis in Lilium and would provide a new perspective for the transcriptional regulation of volatile terpenes in flowers.

萜类化合物是西伯利亚百合香味的主要成分，而LiTPS2在单萜类化合物的生物合成中起着至关重要的作用。尽管“西伯利亚”百合中的主要萜烯合酶已被鉴定，但这些TPS基因在这种独特的花朵中如何进行转录调控仍然难以捉摸。本研究旨在鉴定百合中调节萜烯合成的转录因子，并揭示相关的转录调控机制。在这项研究中，我们鉴定了三个 R2R3-MYB 转录因子——LiMYB1、LiMYB305 和 LiMYB330，它们参与调节百合中萜烯的生物合成。“西伯利亚”。实时定量 PCR 显示空间和时间表达模式与萜烯化合物的发射模式一致。当LiMYB1、LiMYB305和LiMYB330在花中过表达时，一些主要单萜的释放，如芳樟醇和罗勒烯，以及TPS基因的表达，特别是LiTPS2的表达增强。病毒诱导的基因沉默 (VIGS) 测定表明，沉默这三种LiMYB可通过下调TPS基因的表达来降低单萜水平。酵母单杂交和瞬时表达测定表明，所有三种 LiMYB 都能结合并激活LiTPS2 的启动子。此外，酵母双杂交实验验证了LiMYB1可以与LiMYB308和LiMYB330相互作用，表明它们在调节花萜生物合成中发挥协同作用。总的来说，这些结果表明LiMYB1、LiMYB305和LiMYB330可能在百合萜烯生物合成中发挥重要作用，并为花卉中挥发性萜烯的转录调控提供新的视角。