"A genome-wide regulatory framework identifies maize Pericarp Color1 (P1) controlled genes"

KENGO MOROHASHI; MARÍA ISABEL CASAS; LORENA FALCONE FERREYRA; MARÍA KATHERINE MEJÍA-GUERRA; LUCILLE POURCEL; ALPER YILMAZ; ANTJE FELLER; BRUNA CARVALHO; JULIA EMILIANI; EDUARDO RODRIGUEZ; SILVINA PELLEGRINET; MICHAEL MCMULLEN; PAULA CASATI; ERICH GROTEWOLD

PLANT CELL

AMER SOC PLANT BIOLOGISTS

Lugar: Rockville; Año: 2012

1040-4651

Pericarp Color1 (P1) encodes an R2R3-MYB transcription factor responsible for the accumulation of insecticidal flavones inmaize (Zea mays) silks and red phlobaphene pigments in pericarps and other floral tissues, which makes P1 an importantvisual marker. Using genome-wide expression analyses (RNA sequencing) in pericarps and silks of plants with contrasting P1alleles combined with chromatin immunoprecipitation coupled with high-throughput sequencing, we show here that theregulatory functions of P1 are much broader than the activation of genes corresponding to enzymes in a branch of flavonoidbiosynthesis. P1 modulates the expression of several thousand genes, and ;1500 of them were identified as putative directtargets of P1. Among them, we identified F2H1, corresponding to a P450 enzyme that converts naringenin into2-hydroxynaringenin, a key branch point in the P1-controlled pathway and the first step in the formation of insecticidalC-glycosyl flavones. Unexpectedly, the binding of P1 to gene regulatory regions can result in both gene activation andrepression. 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 ofother specialized compounds.