Plant stilbenes are phytoalexins which accumulate in a small number of plant species, including grapevine, in response to biotic and abiotic stresses and have been implicated in many beneficial effects on human health. In particular, resveratrol as basic unit of all other complex stilbenes, has received widespread attention because of its cardio-protective, anti-carcinogenic, and anti-oxidant properties. Although stilbene synthases (STSs), the key enzymes responsible for resveratrol biosynthesis, have been isolated and characterized from several plant species, the transcriptional regulation underlying stilbene biosynthesis is still unknown. Here we report the identification and functional characterization of two R2R3-MYB type transcription factors (TFs) from grapevine, which regulate the stilbene biosynthetic pathway. These TFs, designated VvMYB14 and VvMYB15, strongly co-express with VvSTS genes, both in leaf tissues under biotic and abiotic stress, and in the skin and seed of healthy developing berries during maturation. In transient gene reporter assays, VvMYB14 and VvMYB15 were demonstrated to specifically activate the promoters of VvSTS genes and the ectopic expression of VvMYB15 in grapevine hairy roots resulted in increased VvSTS expression and in the accumulation of glycosylated stilbenes in planta. These results demonstrate the involvement of VvMYB14 and VvMYB15 in the transcriptional regulation of stilbene biosynthesis in grapevine.
The R2R3-MYB Transcription Factors MYB14 and MYB15 Regulate Stilbene Biosynthesis in Vitis vinifera
D'ONOFRIO, CLAUDIO;
2013-01-01
Abstract
Plant stilbenes are phytoalexins which accumulate in a small number of plant species, including grapevine, in response to biotic and abiotic stresses and have been implicated in many beneficial effects on human health. In particular, resveratrol as basic unit of all other complex stilbenes, has received widespread attention because of its cardio-protective, anti-carcinogenic, and anti-oxidant properties. Although stilbene synthases (STSs), the key enzymes responsible for resveratrol biosynthesis, have been isolated and characterized from several plant species, the transcriptional regulation underlying stilbene biosynthesis is still unknown. Here we report the identification and functional characterization of two R2R3-MYB type transcription factors (TFs) from grapevine, which regulate the stilbene biosynthetic pathway. These TFs, designated VvMYB14 and VvMYB15, strongly co-express with VvSTS genes, both in leaf tissues under biotic and abiotic stress, and in the skin and seed of healthy developing berries during maturation. In transient gene reporter assays, VvMYB14 and VvMYB15 were demonstrated to specifically activate the promoters of VvSTS genes and the ectopic expression of VvMYB15 in grapevine hairy roots resulted in increased VvSTS expression and in the accumulation of glycosylated stilbenes in planta. These results demonstrate the involvement of VvMYB14 and VvMYB15 in the transcriptional regulation of stilbene biosynthesis in grapevine.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
