中文摘要：

蔗糖磷酸合成酶（Sucrose phosphate synthase,SPS）是蔗糖合成途径的关键限速酶,在蔗糖积累和碳分配中具有重要作用.在茎组织中SPSⅡ表达量占SPS转录总量的40%,表明SPSⅡ cDNA的克隆与表达对蔗茎中蔗糖的积累有着重要的影响.通过RT-PCR技术克隆分离SPSⅡ基因cDNA片段.序列分析表明该cDNA片段包含1个3 183 bp的开放读码框,可编码1 060个氨基酸.GenBank登录号为EU269038.通过实时荧光定量PCR检测SPSⅡ基因在甘蔗糖分积累的不同时期、不同组织部位的相对表达量.结果表明,在糖分积累初期蔗茎中的SPSⅡ相对表达量最大,在糖分积累中期蔗叶中的SPSⅡ相对表达量达到最高峰;同组织部位中,糖分积累初期SPSⅡ相对表达量高于糖分积累中期、后期.图6参11

英文摘要：

To achieve the ultimate aim of increasing sucrose content in the sugarcane stem,it is necessary to investigate the principal rate-limiting steps in the pathway of sucrose synthesis.It has been suggested that sucrose phosphate synthase（SPS） is a key rate-limiting enzyme in sucrose formation and it also influences sucrose accumulation and carbon partitioning processes.Relative expression of SPSⅡ gene occupies 40% of the total transcription of SPS gene,which shows that the cloning and expression of SPSⅡ gene influences sucrose accumulation process.This research focused on molecular cloning and expression analysis of SPSⅡ gene in sugarcane.The SPSⅡ cDNA fragment was isolated from sugarcane,which contained a 3 183 bp open reading frame（ORF）,encoding 1 060 amino acids.Its Genbank accession no.EU 269038.Relative expression of SPSⅡ gene was determined in the different tissues of sugarcane at different time of sugar accumulation by real-time PCR.The results showed highest relative expression of SPSⅡ gene in the canes at early stage during accumulation process of sucrose,but highest in the leaves at middle stage.In the same photosynthetic tissue,relative expression of SPSⅡ was higher at early stage during accumulation process of sucrose than those at middle stage and later stage.Fig 6,Ref 11