CmWRKY41 activates CmHMGR2 and CmFPPS2 to positively regulate sesquiterpenes synthesis in Chrysanthemum morifolium

Abstract

Chrysanthemum morifolium is one of the most significant multipurpose crops with ornamental, medicinal, and edible value. Terpenoids, an essentials component of volatile oils, are abundant in chrysanthemum. However, the transcriptional regulation of terpenoid biosynthesis in chrysanthemums remains unclear. In the present investigation, we identified CmWRKY41, whose expression pattern is similar to that of terpenoid content in chrysanthemum floral scent, as a candidate gene that may promote terpenoid biosynthesis in chrysanthemum. Two structural genes 3-hydroxy-3-methylglutaryl-CoA reductase 2 (CmHMGR2) and farnesyl pyrophosphate synthase 2 (CmFPPS2), play key role in terpene biosynthesis in chrysanthemum. CmWRKY41 can directly bind to the promoters of CmHMGR2 or CmFPPS2 through GTGACA or CTGACG elements and activate its expression to promote sesquiterpene biosynthesis. In summary, these results indicate that CmWRKY41 targets CmHMGR2 and CmFPPS2 to positively regulate sesquiterpene biosynthesis in chrysanthemums. This study preliminarily revealed the molecular mechanism of terpenoid biosynthesis in chrysanthemum while enriching the secondary metabolism regulatory network.

Keywords: Chrysanthemum; CmWRKY41; Terpenoid biosynthesis; Transcriptional regulation.