Subcellular localization of flavonoid natural products A signaling function?

In a recent paper in Proceedings of the National Academy of Sciences USA, we described genetic mechanisms for the mobilization of pre-formed vacuolar glycoconjugates of isoflavone intermediates for phytoalexin biosynthesis in response to the wound signal methyl jasmonate. While addressing the cellular localizations of glycosyl hydrolases (GHs) that could function in this mobilization, we observed that one jasmonate-induced GH localized to the nucleus, along with a potential product of its activity (7,4'-dihydroxyflavone). These and other observations on the nuclear localization of flavonoids suggest the possibility of as yet unidentified signaling functions for natural products to regulate pathways necessary for plant defense.