Trans-Acting Small Interfering RNA4: key to nutraceutical synthesis in grape development?

The facility and versatility of microRNAs to evolve and change likely underlies how they have become dominant constituents of eukaryotic genomes. TAS4 evolution may be important for biosynthesis of polyphenolics, transport of auxins and biosynthesis of abscisic acid, arbuscular symbiosis, bacterial pathogen etiologies, and the diversification of dicotyledonous flowering plants. Expression-based and phylogenetic evidence shows that TAS4 targets two novel grape MYB transcription factors (VvMYBA6, MYBA7) that spawn phased siRNAs and likely function in nutraceutical bioflavonoid biosynthesis and fruit development. Characterization of the molecular mechanisms of TAS4 control of plant development and integration into biotic and abiotic stress- and nutrient signaling regulatory networks is important for understanding the functions and evolution of miRNAs, non-coding RNAs, and their targets, and has applicability to molecular breeding and development of strategies for engineering healthier