Aquilaria sinensis MYB-Like Transcription Factor AsMYB1 Promotes 2-(2-Phenylethyl)Chromone Biosynthesis Through Interacting With 14-3-3 Family Protein AsGRF1.

2-(2-Phenylethyl)chromones (PECs) are the primary constituents of agarwood, a valuable aromatic resin widely used in traditional oriental medicine and incense production, exhibiting diverse pharmacological activities. While we have previously reported a polyketide synthase (AsPECPS) playing a crucial role in the biosynthesis of PECs in agarwood, the intrinsic regulatory mechanisms underlying PEC biosynthesis remain largely elusive. Here, we successfully characterised a new 1R-subtype myeloblastosis (MYB) transcription factor (AsMYB1) from Aquilaria sinensis whose expression is significantly induced under salt treatment. Further overexpression, RNA interference (RNAi) and gene-editing experiments confirmed the positive regulatory role of AsMYB1 in PEC biosynthesis. AsMYB1 specifically bound to cis-elements in the promoter of AsPECPS to enhance its transcription, thereby promoting PEC accumulation under salt stress. A 14-3-3 family protein designated AsGRF1 was characterised to interact with AsMYB1 both in vivo and in vitro, and knockdown or knockout of AsGRF1 led to a dramatic reduction in AsPECPS expression and PECs' accumulation. Furthermore, AsGRF1 may positively facilitate AsMYB1-mediated activation of PEC production under salt stress by elevating AsPECPS expression through increasing the transcriptional activity, nuclear localisation and stability of AsMYB1. Our findings suggest that the AsGRF1-AsMYB1-AsPECPS module synergistically facilitates salt-induced PEC metabolism, inspiring potential biotechnological strategies to improve agarwood quality through metabolic engineering.