Biosynthesis and antifungal activity of fungus-induced O-methylated flavonoids in maize. Issue 1 (27th October 2021)

• Record Type: Journal Article
• Authors: Förster, Christiane; Handrick, Vinzenz; Ding, Yezhang; Nakamura, Yoko; Paetz, Christian; Schneider, Bernd; Castro-Falcón, Gabriel; Hughes, Chambers C; Luck, Katrin; Poosapati, Sowmya; Kunert, Grit; Huffaker, Alisa; Gershenzon, Jonathan; Schmelz, Eric A; Köllner, Tobias G
• Is Part Of: Plant physiology. Volume 188:Issue 1(2022)
• Page Start: 167
• Page End: 190
• Publication Date: 2021-10-27
• Subjects: Plant physiology -- Periodicals; Botany -- Periodicals; Periodicals; Electronic journals; 571.2
• DOI: 10.1093/plphys/kiab496
• Languages: English
• ISSNs: 0032-0889

Abstract

Abstract: Fungal infection of grasses, including rice ( Oryza sativa ), sorghum ( Sorghum bicolor ), and barley ( Hordeum vulgare ), induces the formation and accumulation of flavonoid phytoalexins. In maize ( Zea mays ), however, investigators have emphasized benzoxazinoid and terpenoid phytoalexins, and comparatively little is known about flavonoid induction in response to pathogens. Here, we examined fungus-elicited flavonoid metabolism in maize and identified key biosynthetic enzymes involved in the formation of O -methylflavonoids. The predominant end products were identified as two tautomers of a 2-hydroxynaringenin-derived compound termed xilonenin, which significantly inhibited the growth of two maize pathogens, Fusarium graminearum and Fusarium verticillioides . Among the biosynthetic enzymes identified were two O -methyltransferases (OMTs), flavonoid OMT 2 (FOMT2), and FOMT4, which demonstrated distinct regiospecificity on a broad spectrum of flavonoid classes. In addition, a cytochrome P450 monooxygenase (CYP) in the CYP93G subfamily was found to serve as a flavanone 2-hydroxylase providing the substrate for FOMT2-catalyzed formation of xilonenin. In summary, maize produces a diverse blend of O -methylflavonoids with antifungal activity upon attack by a broad range of fungi. Abstract : Upon fungal infection, maize produces a complex mixture of O -methylated flavonoids, which are biosynthesized by regiospecific O -methyltransferases and that contribute to the blend of defense-related specialized metabolites.