Variation in promoter of a CYP450 gene contributes to flavonoids and pathogen resistence in Tartary buckwheat

Buckwheat is rich in flavonoid compounds, which not only confer pharmacological value to humans, but also modulate the plant ability to adapt to environmental stresses. This study identified a cytochrome P450 gene (FtCYP81) associated with quercetin through a genome-wide association analysis, which exhibited higher levels of quercetin in hairy root overexpression lines. The gene was significantly induced in the jasmonic acid transcriptome, and the results revealed that the OE-FtCYP81 line in Arabidopsis exhibited enhanced resistance to Rhizoctonia. solani. Further analysis of the promoter sequence showed that a 276-bp deletion in the Hap.2 affected its expression levels, leading to variations in flavonoid content and pathogen resistance among different buckwheat cultivars. Indeed, the upstream region contains a MYB binding element that can directly interact with FtMYB2, thereby activating the expression of FtCYP81 and increasing flavonoid content while enhancing disease resistance. In summary, our study provides insights into the potential relationship between flavonoids and disease resistance, offering promising candidates for the development of new buckwheat varieties with superior agronomic traits.