玉米蔗糖合酶基因启动子的克隆及功能分析

Cloning and functional analysis of the promoter of a maize sucrose synthase gene

蔗糖合酶(sucrose synthase,Su Sy)是植物蔗糖代谢中的一类关键酶,在植物的生长发育过程中具有重要功能。以玉米自交系"B73"的基因组DNA为材料,通过PCR扩增出玉米蔗糖合酶基因SH1起始密码子上游1853 bp序列。生物信息学结果显示该序列含有多个CAAT-box和TATA-box等基本作用元件,参与干旱诱导的MYB结合位点,根、胚乳等器官表达响应元件。构建了由SH1启动子驱动报告基因Gus的植物表达载体,通过农杆菌介导法产生了水稻转化株系,Southern印迹结果显示获得了单拷贝的"中花11"转基因植株(PSH1)。组织化学分析和实时荧光定量PCR结果表明,Gus基因在根、茎、叶、叶鞘及颍壳中高效表达,但在花和种子中不表达。综上可知,SH1启动子是一个新颖的营养器官特异型启动子,在作物的品质改良中具有良好的应用前景。

Sucrose synthase （SuSy） is a key enzyme in sucrose metabolism and plays an important role in regulating plant growth and development. The 1853-bp fragment upstream of the initiation codon of the SH1 gene was amplified from the genomic DNA of the maize inbred line ＂B73＂ using PCR technology. Bioinformatics analysis showed that the gene promoter sequence contains the basic components of CAAT-boxes and TATA-boxes, as well as specific acting elements, such as drought-induced MYB binding sites and a cis-regulatory element in- volved in root or endosperm expression. The promoter fused with the Gus gene in an Agrobacterium binary vector was constructed for Agrobacterium-mediated transformation of the rice variety ＇Zhouhua 11＇. Southern blot analysis showed that three＇ transgenic rice plants （PSH1） contained single copy of the transgene. Histochemical analysis and real-time PCR exhibited that the Gus gene driven by SH1 promoter had a strong expression in roots, stems, leaves, sheaths, and glumes, but gene expression was not detected in flowers and seed tissues. Thus, we suggested that SH1 promoter is a novel vegetative tissue-specific promoter and has significant potential for crop quality improvement.