Expression Analysis and Functional Verification of the LiMYC1 Related to Lavender (Lavandula × intermedia) Terpenoid Synthesis
XUE Zhi-Hang1,2, Maierziyaguli•ABULAIKEMU1,2, WANG Ai-Fan1,2, LIAO Yan1,2, YAN Zhong-Jian1,2, SU Xiu-Juan1,2,*, GUO Dan-Li3,*
1 College of Agriculture, Xinjiang Agricultural University, Urumqi 830052, China; 2 Lavender Research Institute/Xinjiang Key Laboratory of Crop Biological Breeding, Xinjiang Agricultural University, Urumqi 830052, China; 3 Institute of Agriculture Sciences, the Fourth Agriculture Production Division of Xinjiang Production and Construction Crops, Cocodala 835219, China
Abstract：Lavender (Lavandula angustifolia) is an important spice cash crop in the world. The essential oil extracted from the inflorescence is rich in aromatic compounds. These compounds mainly rely on the methylerythritol-4-phosphate (MEP) pathway in plant plastids for metabolic synthesis. In the MEP pathway, 1-deoxy-D-xylose-5-phosphate synthase (DXS) and 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR), as the first 2 key rate-limiting enzymes, play a decisive role in the smooth progress of the whole metabolic process. The LiMYC1 (myelocytomatosis 1) gene cloned from Lavandula × intermedia was targeted, and its function in the synthesis of volatile terpenoids was verified. In this study, The pCAMBIA3301 and pTRV2 plant expression vectors were constructed, and overexpression and gene-silencing plants were obtained using Agrobacterium-mediated genetic transformation methods. The expression of LiMYC1, LiDXS and LiDXR genes in transgenic plants were detected, and volatile terpenoids in leaves were qualitatively and quantitatively analyzed. The results showed that in the LiMYC1 gene overexpression line, the expression of LiDXS and LiDXR increased significantly, and the contents of linalool and caryophyllene also increased to varying degrees. On the contrary, in the LiMYC1 gene silenced strain, the expression of LiDXS and LiDXR were significantly reduced, and the content of caryophyllene was reduced, but the content of linalool was abnormally increased. The above results indicated that the LiMYC1 gene positively regulated the MEP pathway of terpenoid synthesis, affected the expression of key enzymes LiDXS and LiDXR, and had a certain regulatory effect on the biosynthesis of caryophyllene and linalool. This study has important guiding significance for analyzing the molecular mechanism of lavender aroma formation and optimizing the economic value of lavender.
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