The transcription factor BoCOL15 mediates ABA-induced sulforaphane accumulation in broccoli sprouts via a dual-action regulatory mechanism

Sulforaphane (SFN), a high-value nutraceutical derived from glucosinolates (GSLs) in broccoli sprouts, can be enhanced by the plant hormone abscisic acid (ABA). However, the underlying molecular mechanism is poorly understood, limiting its practical application. Here, we used an integrated approach combining metabolomics, time-series transcriptomics, and molecular validation to elucidate how exogenous ABA regulates GSLs metabolism in broccoli sprouts. Treatment with 50 μmol/L ABA resulted in a 1.89-fold increase in SFN content. Metabolomics revealed that ABA selectively remodeled the GSLs profile, preferentially promoting short-chain aliphatic GSLs while inhibiting indolic GSLs. Transcriptomics uncovered a dual-action mechanism: ABA upregulated key GSL biosynthesis genes ( BCAT2 , SUR1 , SOT17 ) and simultaneously downregulated the epithiospecifier protein ( ESP ) gene, which diverts hydrolysis away from SFN. This coordinated regulation ensures efficient SFN accumulation. Weighted Gene Co-expression Network Analysis (WGCNA) identified BoCOL15 as a key ABA-responsive transcription factor. Yeast one-hybrid and dual-luciferase assays confirmed that BoCOL15 directly binds to and activates the promoters of two core biosynthesis genes, BoGGP1 and BoSOT17 . In conclusion, ABA enhances SFN through a BoCOL15 -mediated dual mechanism that both boosts precursor synthesis and guides metabolic flux. BoCOL15 is a novel molecular hub connecting ABA signaling to GSLs metabolism and represents a prime target for the molecular breeding and biofortification of broccoli.