TcMYC2 regulates Pyrethrin biosynthesis in .

Pyrethrins constitute a class of terpene derivatives with high insecticidal activity and are mainly synthesized in the capitula of the horticulturally important plant, Treatment of with methyl jasmonate (MeJA) in the field induces pyrethrin biosynthesis, but the mechanism linking MeJA with pyrethrin biosynthesis remains unclear. In this study, we explored the transcription factors involved in regulating MeJA-induced pyrethrin biosynthesis. A single spray application of MeJA to leaves rapidly upregulated the expression of most known pyrethrin biosynthesis genes and subsequently increased the total pyrethrin content in the leaf. A continuous 2-week MeJA treatment resulted in enhanced pyrethrin content and increased trichome density. , a key gene in jasmonate signaling, was screened at the transcriptome after MeJA treatment. positively regulated expression of the pyrethrin biosynthesis genes , , and by directly binding to E-box/G-box motifs in the promoters. The stable overexpression of in hairy roots significantly increased the expression of and . Further transient overexpression and viral-induced gene-silencing experiments demonstrated that positively promoted pyrethrin biosynthesis. Collectively, the results reveal a novel molecular mechanism for MeJA-induced pyrethrin biosynthesis in involving TcMYC2.