Kobayashi S, Ishimaru M, Hiraoka K, Honda C
Department of Grape and Persimmon Research, National Institute of Fruit Tree Science, Akitsu, Hiroshima 729-2494, Japan.
Planta. 2002 Oct;215(6):924-33. doi: 10.1007/s00425-002-0830-5. Epub 2002 Jul 16.
Partial cDNAs of myb-related regulatory genes were isolated from the tetraploid Kyoho grape ( Vitis labruscana: V. labrusca x V. vinifera) and the expression patterns of the corresponding genes were studied. Since MybA gene expression is closely related to coloring and/or ripening of the berry (expression increases strongly with the commencement of coloring and berry softening, and is detected only in berry skin and flesh), full-length cDNAs for the gene were isolated from a mature-berry cDNA library. Three different species of MybA were identified from the cDNA sequences. Delivery of these cDNAs to somatic embryos of grape led to the induction of reddish-purple spots and UDP-glucose:flavonoid 3- O-glucosyltransferase (UFGT) gene expression in non-colored embryos. The UFGT transcript was not detected in control embryos, while other structural genes for anthocyanin biosynthesis were expressed in both control and pigmented embryos. In addition, introduction of the UFGT gene induced the same reddish-purple spots in embryos. In contrast, treatment with the leucoanthocyanidin dioxygenase (LDOX) gene failed to induce these spots. Our results strongly suggest that MybA genes are involved in the regulation of anthocyanin biosynthesis in the grape via expression of the UFGT gene.
从四倍体巨峰葡萄（美洲葡萄：美洲葡萄×欧亚葡萄）中分离出与myb相关的调控基因的部分cDNA，并研究了相应基因的表达模式。由于MybA基因的表达与浆果的着色和/或成熟密切相关（随着着色和浆果软化的开始，表达强烈增加，且仅在浆果的果皮和果肉中检测到），因此从成熟浆果cDNA文库中分离出该基因的全长cDNA。从cDNA序列中鉴定出三种不同的MybA。将这些cDNA导入葡萄体细胞胚中，可诱导未着色胚中出现红紫色斑点，并诱导UDP-葡萄糖：类黄酮3-O-葡萄糖基转移酶（UFGT）基因表达。在对照胚中未检测到UFGT转录本，而花青素生物合成的其他结构基因在对照胚和色素沉着胚中均有表达。此外，导入UFGT基因也能在胚中诱导出相同的红紫色斑点。相比之下，用无色花青素双加氧酶（LDOX）基因处理未能诱导出这些斑点。我们的结果有力地表明，MybA基因通过UFGT基因的表达参与葡萄中花青素生物合成的调控。
