中文摘要：

甘蔗是我国南方地区重要的糖料作物。为达到增糖的育种目标，对甘蔗蔗糖积累主要限速步骤的研究是必不可少的。蔗糖磷酸合成酶（SPS）作为蔗糖合成途径的关键限速酶，对甘蔗中蔗糖合成和碳水化合物分配有着重要的影响。本研究采用长距离PCR法（LD—PCRl克隆到两条不同长度的甘蔗（Saccharumspp．CV．FN95—1702）SPSIU基因组DNA片段。序列分析表明，所得的片段基因结构相同，均含有13个外显子和12个内含子，其开放读码框（ORF）编码964个氨基酸，序列提交GenBank，获得查询登陆号EU278617、EU278618。以此为基础，继续从甘蔗基因组中扩增出先前未知的SPSⅢ基因5’侧翼序列，申请GenBank登陆号KC422670。转录因子结合位点生物信息学分析表明，该序列含有顺式DNA作用元件和启动子TATA启动盒。为进一步验证5’侧翼序列的启动子活性，分别截取5段不同长度的SPSⅢ基因5’侧翼序列与报告基因GUS融合，构建嵌合基因表达载体质粒，基因枪微弹轰击甘蔗愈伤组织观测瞬时表达，证实了所克隆到的5’侧翼序列具有启动子活性，是甘蔗SPSⅢ基因的启动子，且具有一定的表达特性。本研究通过克隆分析SPSⅢ基因以其启动子，为研究基因结构和生物学功能提供了基础资料。

英文摘要：

Sugarcane （Saccharum spp.） is a commercial important sugar crop in South China. In order to achieve the breeding aim of increasing sugar yield, it is essential to focus on the principal rate limiting steps in sugarcane sucrose accumulation processes. Sucrose phosphate synthase （SPS） is considered a key rate- limiting enzyme in the pathway of sucrose synthetization and carbon partitioning processes. In this study, two different genomic DNA framents（GenBank accession No. EU278617 and EU278618） which encoding Sugarcane SPS III protein were cloned by long distance PCR（LD-PCR）. DNA Exon-intron structure analysis suggested that both sequences contained twelve introns, thirteen exons, and the open reading frame encoded a protein of 964 amino acids. Subsequently, the 5＇-flanking sequence （GenBank accession No. KC422670） of SPSⅢ was aslo isolated from sugarcane genome DNA using Adaptor-ligation PCR method. This novel sequence contained the important DNA putative cis-acting elements as well as TATA box. To identify promoter activtity of SPSⅢ, we generated five different vectors which contained different length of the 5＇- flanking fragment fused to the the β-glucuronidase （GUS） reporter gene. Transient expression experimen was carried out by the method of particle bombardment. Histochemical activity of b-glucuronidase was observed in callus. The gene expression results confirmed its promoter activtity. This stuty will provide theory basis for further study on the gene structure and biological function of SPSⅢ via gene clone and promoter analysis.