RESUMEN
MYBA2 transcription factor (Myb-related gene) affects the coloring in grapevine berry and plays an important role in the biosynthesis of anthocyanin. The MYBA2 gene was cloned from Vitis vinifera L. cv. Cabernet Sauvignon and polyclonal antibodies for VvmybA2 were prepared. The VvmybA2 gene expression patterns were observed in seven tissues (the leaf, stem, flower, bud, root, berry, and tendril) and during the berry development stage at transcriptional and translational levels, respectively. The results indicated that the expression of VvmybA2 was approximately 11-fold higher in the berry than that in the other six tissues, and increased rapidly from 60 days after full bloom reaching a maximum on day 80. Furthermore, both the anthocyanin content and UDP-glucose:flavonoid-3-O-glucosyltransferase (UFGT) gene expression levels increased rapidly 60 days after full bloom. Moreover, correlation analysis indicated that the transcriptional and translational expression levels of the VvmybA2 gene were significantly positively correlated with not only UFGT and DFR genes but also with the anthocyanin content during berry development. These results suggested that VvmybA2 could not only regulate the transcription of both UFGT and DFR but also is involved in the expression of the UFGT gene associated with color determination in grape berries.
Asunto(s)
Antocianinas/biosíntesis , Flavonoles/biosíntesis , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Vitis/metabolismo , Oxidorreductasas de Alcohol/genética , Antocianinas/genética , Clonación Molecular , Flavonoles/genética , Frutas/metabolismo , Regulación de la Expresión Génica de las Plantas , Glucosiltransferasas/genética , Especificidad de Órganos , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Vitis/genéticaRESUMEN
To examine the effect of postharvest ultraviolet C (UV-C) irradiation on flavanol polyphenol accumulation in the grape berry, we investigated total flavanol polyphenol content, the enzyme activity of leucoanthocyanidin reductase (LAR), and transcription of Vv lar1 and Vv lar2 using spectrophotometry, real-time polymerase chain reaction, and western blot analysis in 5-year-old Vitis vinifera L. cv. Cabernet Sauvignon plants. Our results indicated that the accumulation of flavanol polyphenol reached its highest value when exposed to UV-C irradiation for 30 min. Additionally, UV-C irradiation induced the transcription of Vv lar1 and Vv lar2 and the synthesis of LAR1 and LAR2 proteins, resulting in increased accumulation of flavanol polyphenol in the grape berry. Moreover, these effects were associated with the length of time of UV-C irradiation.