Expression of flavonoid 3’-hydroxylase is controlled by P1, the regulator of 3-deoxyflavonoid biosynthesis in maizeReport as inadecuate

Expression of flavonoid 3’-hydroxylase is controlled by P1, the regulator of 3-deoxyflavonoid biosynthesis in maize - Download this document for free, or read online. Document in PDF available to download.

BMC Plant Biology

, 12:196

Biochemistry and physiology


BackgroundThe maize Zea mays red aleurone1 pr1 encodes a CYP450-dependent flavonoid 3’-hydroxylase ZmF3’H1 required for the biosynthesis of purple and red anthocyanin pigments. We previously showed that Zmf3’h1 is regulated by C1 Colorless1 and R1 Red1 transcription factors. The current study demonstrates that, in addition to its role in anthocyanin biosynthesis, the Zmf3’h1 gene also participates in the biosynthesis of 3-deoxyflavonoids and phlobaphenes that accumulate in maize pericarps, cob glumes, and silks. Biosynthesis of 3-deoxyflavonoids is regulated by P1 Pericarp color1 and is independent from the action of C1 and R1 transcription factors.

ResultsIn maize, apiforol and luteoforol are the precursors of condensed phlobaphenes. Maize lines with functional alleles of pr1 and p1 Pr1;P1 accumulate luteoforol, while null pr1 lines with a functional or non-functional p1 allele pr1;P1 or pr1;p1 accumulate apiforol. Apiforol lacks a hydroxyl group at the 3’-position of the flavylium B-ring, while luteoforol has this hydroxyl group. Our biochemical analysis of accumulated compounds in different pr1 genotypes showed that the pr1 encoded ZmF3’H1 has a role in the conversion of mono-hydroxylated to bi-hydroxylated compounds in the B-ring. Steady state RNA analyses demonstrated that Zmf3’h1 mRNA accumulation requires a functional p1 allele. Using a combination of EMSA and ChIP experiments, we established that the Zmf3’h1 gene is a direct target of P1. Highlighting the significance of the Zmf3’h1 gene for resistance against biotic stress, we also show here that the p1 controlled 3-deoxyanthocyanidin and C-glycosyl flavone maysin defence compounds accumulate at significantly higher levels in Pr1 silks as compared to pr1 silks. By virtue of increased maysin synthesis in Pr1 plants, corn ear worm larvae fed on Pr1; P1 silks showed slower growth as compared to pr1; P1 silks.

ConclusionsOur results show that the Zmf3’h1 gene participates in the biosynthesis of phlobaphenes and agronomically important 3-deoxyflavonoid compounds under the regulatory control of P1.

KeywordsAnthocyanins Flavones Flavonoids F3’H Maysin Phlobaphenes Electronic supplementary materialThe online version of this article doi:10.1186-1471-2229-12-196 contains supplementary material, which is available to authorized users.

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Author: Mandeep Sharma - Chenglin Chai - Kengo Morohashi - Erich Grotewold - Maurice E Snook - Surinder Chopra


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