A genome-wide regulatory framework identifies maize Pericarp Color1 controlled gene

MOROHASHI, K.; CASAS, M. I.; FALCONE-FERREYRA, M. L.; MEJÍA GUERRA, M. K.; POURCEL, L.; YILMAZ, A.; FELLER, A.; CARVALHO, B.; EMILIANI, J.; RODRIGUEZ, E.; PELLEGRINET, S.; MCMULLEN, M.; CASATI, P.; GROTEWOLD,E.

PLANT CELL

AMER SOC PLANT BIOLOGISTS

Lugar: Rockville; Año: 2012 vol. 24 p. 2745 - 2764

1040-4651

Pericarp Color1 (P1) encodes an R2R3-MYB transcription factor responsible for the accumulation of insecticidal flavones in maize (Zea mays) silks and red phlobaphene pigments in pericarps and other floral tissues, which makes P1 an important visual marker. Using genome-wide expression analyses (RNA sequencing) in pericarps and silks of plants with contrasting P1 alleles combined with chromatin immunoprecipitation coupled with high-throughput sequencing, we show here that the regulatory functions of P1 are much broader than the activation of genes corresponding to enzymes in a branch of flavonoid biosynthesis. P1 modulates the expression of several thousand genes, and ca. 1500 of them were identified as putative direct targets  of  P1.  Among  them,  we  identified  F2H1,  corresponding  to  a  P450  enzyme  that  converts  naringenin  into 2-hydroxynaringenin, a key branch point in the P1-controlled pathway and the first step in the formation of insecticidal C-glycosyl flavones. Unexpectedly, the binding of P1 to gene regulatory regions can result in both gene activation and repression. Our results indicate that P1 is the major regulator for a set of genes involved in flavonoid biosynthesis and a minormodulator of the expression of a much larger gene set that includes genes involved in primary metabolism and production of other specialized compounds.