OfWRKY33 binds to the promoter of key linalool synthase gene to stimulate linalool synthesis in flowers.

Volatile aroma compounds make significant contributions to human perception of flowers. is a famous aroma plant, and linalool is proved to be the dominant aroma active compound. Although some terpene synthases have been characterized, a comprehensive study of the hub metabolic gene and its transcriptional regulation remain to be revealed. Here, we selected a specific cultivar Boyeyingui with the highest content of linalool among 20-wide-cultivated cultivars for genome and transcriptome sequencings. Among the 25 new putative only , could exclusively produce linalool . Biochemical analysis demonstrated that OfTPS6, OfTPS7 were able to catalyze geranyl diphosphate into linalool and a small proportion of other monoterpenes . Spatial and temporal correlation analysis further confirmed the expression level of was strongly correlated with linalool content in a panel of 20 cultivars, suggesting was the essential linalool synthase gene. Combined with yeast one-hybrid screen and weighted correlation network analysis, a nucleus-localized transcriptional factor OfWRKY33 was identified as a prospective modulator. Y1H, LUC, and EMSA demonstrated that OfWRKY33 directly bound to the W-box of promoter to stimulate its transcription. OfWRKY33 could coordinately induce the expressions of and 1-deoxy-d-xylulose 1, thereby promoting the linalool formation The results first identified the key linalool synthase gene and a novel transcription factor playing a role in the complex regulatory network of linalool biosynthesis in flowers.