Transcriptomic and metabolomic analysis reveals the difference between large and small flower taxa of Herba Epimedii during flavonoid accumulation

Herba Epimedii, as a traditional Chinese herb, is divided into large and small flower taxa, and can invigorate sexuality and strengthen muscles and bones. Herba Epimedii is rich in flavonoids, which largely contribute to its medicinal benefits. In our previous studies, we have found that the flavonoids content was much more in small than large flower taxa. To further identify molecular mechanisms of flavonoids metabolism in Herba Epimedii, combined metabolome and transcriptomic analyses were performed to profile leaves and flowers. Association analysis revealed that the expression of genes involved in flavonoid biosynthesis showed significant differences between small and large flower taxa. Eleven flavonols significantly increased in small compared to large flower taxa. Moreover, genes encoding O-methyltransferase played crucial roles in flavonoids metabolism by an integrated analysis. Taken together, these data highlight the breeding tendency of small flower taxa to improve the quality of Herba Epimedii.