苹果矮化砧木T337 MdCBB1基因的克隆与表达分析
Cloning and Expression Analysis of MdCBB1 Genes in Apple Rootstock T337

为研究油菜素内酯（BR）对苹果矮化砧木T337株高调控机制的影响，以T337盆栽苗为试材，利用RT-PCR技术从T337中分离出BR合成关键基因 MdCBB1.1和 MdCBB1.2，二者的开放阅读框均为1 707 bp，分别编码一个568个氨基酸的蛋白，分子质量分别为6.624 1×10 ku和6.622 8×10 ku。生物信息学分析结果显示， MdCBB1.1和 MdCBB1.2基因编码的蛋白含有FAD_binding_4和GlcD 2个明显的结构域，为非核蛋白，属于植物CBB1蛋白家族。表达分析结果显示， MdCBB1.1和 MdCBB1.2基因在T337不同组织均有表达，但是顶梢和根中的表达量明显高于其他组织 (P<0.05)。并且外源芸苔素内酯（BL）处理能够上调二者在木质部中的表达(P<0.05)。
To investigate the mechanism of brassinolide (BR) affecting the height of apple dwarf rootstock T337, T337 seedlings were used for research. Full-length MdCBB1.1 and MdCBB1.2 genes were isolated from T337 by using RT-PCR technology. Both MdCBB1.1 and MdCBB1.2, playing a key role in BR biosynthesis, comprises a 1 707 bp open reading frame, encoding a 568 amino acids protein with the molecular mass of 6.624 1×10 ku and 6.622 8×10 ku, respectively. Bioinformatics analysis revealed that the predicted protein is not nucleoprotein and including the typical sequences of CBB1 family: the FAD_binding_4 and GlcD domain. The expression analysis indicated that both MdCBB1.1 and MdCBB1.2 genes expressed in different tissues of T337, but the expression amount differed significantly (P<0.05). The higher level of the expression was detected in shoot tip and root. Moreover, in xylem, the transcript level of MdCBB1.1 and MdCBB1.2 were increased by the exogenous BL (P<0.05).