Unraveling the regulation of floral fragrance biosynthesis

Floral volatiles are biologically and economically important plant derived chemical compounds. In petunia, floral volatile benzenoid/phenylpropanoid (FVBP) biosynthesis is controlled spatially, developmentally, and hormonally at molecular, metabolic, and biochemical levels. Over the last years, numerous genes have been shown to encode proteins that either directly catalyze a biochemical reaction yielding FVBP compounds, or are involved in metabolite flux prior to the formation of FVBP compounds. This FVBP gene network is specifically and coordinately transcribed. Multiple R2R3-MYB transcription factors are involved in the regulation of genes in the core metabolic pathways leading to a very unique mixture of emitted floral volatiles. The molecular puzzle is not complete, since the functions of the few FVBP transcription factors identified to date do not fully explain the transcriptional regulation of the entire gene network.