EbMYBP1, a R2R3-MYB transcription factor, promotes flavonoid biosynthesis in Erigeron breviscapus

<i>Erigeron breviscapus</i>, a traditional Chinese medicinal plant, is enriched in flavonoids that are beneficial to human health. While we know that R2R3-MYB transcription factors (TFs) are crucial to flavonoid pathway, the transcriptional regulation of flavonoid biosynthesis in <i>E. breviscapus</i> has not been fully elucidated. Here, <i>EbMYBP1</i>, a R2R3-MYB transcription factor, was uncovered as a regulator involved in the regulation of flavonoid accumulation. Transcriptome and metabolome analysis revealed that a large group of genes related to flavonoid biosynthesis were significantly changed, accompanied by significantly increased concentrations of the flavonoid in <i>EbMYBP1-</i>OE transgenic tobacco compared with the wild-type (WT). <i>In vitro</i> and <i>in vivo</i> investigations showed that <i>EbMYBP1</i> participated in flavonoid biosynthesis, acting as a nucleus-localized transcriptional activator and activating the transcription of flavonoid-associated genes like <i>FLS</i>, <i>F3H</i>, <i>CHS</i>, and <i>CHI</i> by directly binding to their promoters. Collectively, these new findings are advancing our understanding of the transcriptional regulation that modulates the flavonoid biosynthesis.