Salicylic acid regulates biosynthesis of floral fragrance (E)-β-farnesene via NPR3-WRKY1 module in chrysanthemum.

Floral fragrance is essential for the attraction of pollinators and responses to biotic and abiotic stresses. It also enhances the quality and economic value of plants. Phytohormones, acting as key signaling molecules, are crucial roles in regulating plant growth and development. However, the molecular mechanisms underlying the biosynthesis of fragrance-related volatiles and their crosstalk with other endogenous signals within plants remain largely unknown. Here, we identified a sesquiterpene synthase gene, CmEβFS, in chrysanthemum, which encodes a catalytic enzyme responsible for synthesizing the key fragrance-related compound (E)-β-farnesene. We demonstrated that CmEβFS is negatively regulated by CmWRKY1, thereby inhibiting (E)-β-farnesene biosynthesis. Furthermore, CmWRKY1 interacts with the salicylic acid (SA) receptor CmNPR3 to regulate SA-mediated CmEβFS transcription. Our findings reveal that SA regulates (E)-β-farnesene biosynthesis by controlling CmEβFS expression via the CmWRKY1-CmNPR3 module during floral development. These findings enhanced our understanding of the mechanisms underlying SA-mediated regulation of volatile organic compounds (VOCs) biosynthesis and provided insights into improving floral fragrance.