Erich Grotewold

Dept. of Plant Biology and Plant Biotechnology Center

The Ohio State University, Columbus, OH 43210

The possibility to utilize transcription factors to manipulate the accumulation of plant compounds is attractive, as it provides an opportunity to induce entire metabolic pathways, overcoming flux limitations, by introducing into plants a single transgene. We have previously demonstrated that this approach works, using maize flavonoid biosynthesis as a model system. In maize, two branches of flavonoid biosynthesis are independently regulated by the Myb-domain proteins P and C1, providing one of the best understood regulatory networks in plants. The ectopic expression of the P and C1 regulators in cultured maize Black Mexican Sweet (BMS) cells induced the accumulation of two different classes of flavonoids. Moreover, analysis of the compounds induced by the ectopic expression of these Myb factors indicated that they play novel regulatory functions, not obvious from previous studies. Thus, the ectopic expression of transcription factors in cultured plant cells provides a convenient mean to engineer plant metabolism and to elucidate the function of transcriptional regulators.