MYB transcription factors represent a family of genes that include the conserved MYB DNA-binding domain, and they are widely involved in the regulation of plant development and secondary metabolism. In this study, Part of sequences of two MYB transcription factors was determined through the cDNA microarray hybridization and selection of cDNA library derived from tender shoots. The full-length cDNAs of the genes were obtained with RT-PCR and RACE, and they were 1 132 bp and 1 020 bp, named as CsMYBl and CsMYB2 ( GenBank accession No. HQ660373 and HQ660374) , and contained ORFs of 879 bp and 675 bp encoding 292 and 224 ami no acids, respectively. Sequences analysis showed that the deduced protein molecular weight of the two genes were 32.9 ku and 25.4 ku, and the proteins contained two conserved MYB domains near the N-tenninus and a conserved Cl motif near the R3 domains. The deduced amino acid sequence of CsMYBl and CsMYB2 from tea plant showed high identity with that of other plants, for instance CsMYBl shared 57% homology with MYB1 of Gossypium hirsutum and CsMYB2 shared 75% homology wilh MYBC2 of Vitis vinifera. The result of real time-PCR analysis showed the two genes were expressed constitutively in all tissues with different expression levels, e. g. the relative expression level of CsMYB2 in leaf was hundred times higher than that in root. Additionally, shading enhanced CsMYBl expression, while the treatment did not alter the expression level of CsMYB2.%MYB类转录因子是一类包含一段保守的DNA结合结构域的基因家族,广泛地参与植物发育和植物次生代谢的调节.根据前期芯片杂交和文库筛选得到的2个MYB转录因子的部分序列,采用RT-PCR和RACE技术分离得到它们的全长基因:C3MYBI和C3MYB2,在GenBank的登录号分别为HQ660373和HQ660374.序列分析表明:CsMYBI基因全长1132bp,开放阅读框长879bp,编码292个氨基酸,推测的蛋白分子量约为32.9ku,理论等电点为8.13:CsMYB2基因全长1020bp,其中开放阅读框长675bp,编码224个氨基酸,推测的蛋白分子量约为25.4ku,理论等电点为9.05.2个基因编码的蛋白均具有明显的R2R3M YB结构域,且在R3结构域的下游都含有1个相对保守的C1(LIXXGIDPXTHR)基序.同源性分析表明:茶树CsM YBI和CsMYB2编码的氨基酸序列与其他植物的MYB类转录因子具有较高的相似性,其中CsMYBI编码的氨基酸序列与陆地棉MYBI的相似性为57％,CsMYB2编码的氨基酸序列与葡萄MYBC2的相似性为75％.利用荧光定量PCR技术检测2个转录因子基因在遮荫处理条件下的表达规律,及其在茶树不同组织中的表达特性,结果表明:CsMYBI和CsM YB2在不同组织中均有表达,但表达量具有明显区别,其中CsM YB2在叶片中的相对表达量是根中的100多倍；而遮荫处理能明显降低叶片中的花青素含量,并提高CsMYBI的表达,但对转录因子CsMYB2的影响不大.
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