RNA silencing in white petunia flowers creates pigmentation patterns invisible to the human eye.

Modern commercial petunias exhibit a wide range of flower colors, which can be observed in gardens. In this study, we present a petunia cultivar that exhibits a floral pattern that is invisible to humans but is possibly visible to pollinating insects. We show that this hidden pattern is established by differentially localized accumulation of flavonols and cinnamic acid derivatives in the corolla limb. This accumulation is caused by a combination of two distinct mechanisms that inhibit anthocyanin biosynthesis: a loss-of-function mutation in the ANTHOCYANIN2, and localized RNA-silencing of CHALCONE SYNTHASE-A.