Transcription activator involved in the spatiotemporal regulation of flavonoid biosynthesis specifically in the corms of Montbretia (PubMed:31004005). Activates the promoters of enzymes involved in the biosynthesis of the flavonol myricetin and the flavonol-glycoside montbretin A (MbA) (PubMed:31004005). MbA is a potent inhibitor of human pancreatic alpha-amylase and is being developed as drug candidate to treat type-2 diabetes (PubMed:31004005).