Transcriptomic and metabolomic profiling reveal the role of BoMYB2 in flavor regulation mechanism and coloration in the postharvest purple cauliflower

Purple (Pr) mutant cauliflower has a bright color and high nutritional value. During postharvest storage, purple cauliflower fades in color and gradually develops a pungent flavor, which directly affects its commercial value. In this study, six anthocyanin-related metabolites were identified in postharvest Pr mutants via metabolomic analyses. Gene-metabolite association analysis revealed that 6-gingerol was the main component responsible for the pungent flavor of the Pr mutant, and that this compound was a component of the stilbenoid, diarylheptanoid, and gingerol biosynthesis pathways. The pungent flavor was correlated with the expression level of caffeoyl coenzyme A O-methyltransferase (CCoAOMT). In vitro experiments confirmed that the transcription factor (TF) BoMYB2 specifically binds to the BoCCoAOMT promoter through the MBS site. Additionally, transient expression analysis confirmed that BoMYB2 negatively regulates BoCCoAOMT transcription and promotes 6-gingerol accumulation, thereby influencing flavor formation in the Pr mutant. Our findings reveal the key genes and TF for the flavor-related transcriptional regulatory mechanism of postharvest Pr mutant cauliflower, and provide a valuable basis for developing postharvest preservation technology for commercial crops.

Automated summary

This study identified six anthocyanin-related metabolites in postharvest Pr mutants of purple cauliflower using metabolomic analyses. The main component responsible for the pungent flavor of the Pr mutant was found to be 6-gingerol, which is involved in several biosynthesis pathways. The expression level of caffeoyl coenzyme A O-methyltransferase (CCoAOMT) was correlated with the pungent flavor, and the transcription factor (TF) BoMYB2 was found to negatively regulate BoCCoAOMT transcription and promote 6-gingerol accumulation.