The molecular mechanism of transforming red light signal to (E)-β-caryophyllene biosynthesis in Arabidopsis.

Abstract

It is known that red light irradiation enhances the biosynthesis of (E)-β-caryophyllene in plants. However, the underlying mechanism connecting red light to (E)-β-caryophyllene biosynthesis remains elusive. This study reveals a molecular cascade involving the phyB-PIF4-MYC2 module, which regulates (E)-β-caryophyllene biosynthesis in response to the red light signal in Arabidopsis thaliana. In this module, phyB positively regulates (E)-β-caryophyllene biosynthesis under red light, whereas PIF4 negatively regulates it; both regulations require the involvement of MYC2, a transcription factor that can bind directly to the promoter of the TPS21 gene which encodes (E)-β-caryophyllene synthase. Importantly, protein-protein and protein-DNA interaction assays show that PIF4 reduces the binding affinity of MYC2 to the TPS21 promoter through direct interaction with MYC2. We propose that the phyB-PIF4-MYC2 module represents a universal mechanism linking red light to sesquiterpene biosynthesis in plants.