Manipulating the accumulation of phenolics in maize cultured cells using transcription factors

Transcription factors are emerging as powerful tools to manipulating plant metabolism. R2R3 Myb genes have expanded dramatically in the plants, where they are involved in the regulation of plant form and metabolic diversity. However, the function of most plant R2R3 Myb genes remains to be determined. We have used a maize cell culture system to investigate the consequences on the accumulation of metabolites of expressing the novel R2R3 Myb transcription factor ZmMyb-IF35. We show here that, despite the high identity in the Myb domain with the P regulator of 3-deoxy flavonoid biosynthesis, ZmMyb-IF35 does not induce the accumulation of flavonoids. However, similar to P, ZmMyb-IF35 induces the accumulation of ferulic and chlorogenic acids as well as several other compounds not found in the control Black Mexican Sweet maize cell lines or in P-expressing lines. Together, our studies show that ZmMyb-IF35 and P activate different biosynthetic pathways, and suggest a promising role of ZmMyb-IF35 for engineering the accumulation of various phenolic compounds. (C) 2003 Elsevier Science B.V. All rights reserved.