中文摘要：

为了从分子水平上揭示不同小麦品种（系）间抗性淀粉含量差异的原因,本试验利用q RT-PCR技术研究了抗性淀粉含量高和抗性淀粉含量低的小麦品种（系）淀粉合成关键基因SBEⅡa表达差异。根据Genebank中公布的小麦SBEⅡa基因启动子（AY357072.1）基因序列设计特异性引物,利用RT-PCR技术克隆SBEⅡa基因启动子,利用Clustal.W对测序结果比对分析,利用数据库PLACE和Plant CARE对启动子序列中各特征元件进行预测,以发掘影响SBEⅡa基因表达量的重要作用元件的等位变异位点。结果显示：抗性淀粉含量高的小麦品种（系）中SBEⅡa基因的表达量低于抗性淀粉含量低的品种（系）。克隆了10个抗性淀粉含量不同的小麦品种（系）SBEⅡa基因编码区上游2896 bp序列,10个小麦品种（系）SBEⅡa基因启动子序列相似性达到了99.92%,抗性淀粉含量高和抗性淀粉含量低的小麦品种（系）SBEⅡa基因启动子序列间无规律性差异。推测,SBEⅡa基因启动子可能不是造成SBEⅡa基因表达差异的主要原因。

英文摘要：

In order to explore the molecular mechanism that different spring wheat cultivars show significantly differences in RS（resistant starch,RS） content,we studied the gene expression profiles of SBEⅡ a which is a key gene controlling starch synthesis between cultivars and two low RS conent cultivars of spring wheat by quantitative real-time RT-PCR（q RT-PCR） technique.Special primers were designed according the sequence of AY357072.1 deposited in Gen Bank,and the partial sequence of SBEⅡ a gene promoter was cloned using reverse transcription polymerase chain reaction（RT-PCR） from wheat.The nucleotide sequences were blasted by Clustal.W software,and the regulatory elements were predicted by PLACE and Plant CARE, respectively.The results showed that the relative expression level of SBEⅡ a in high RS spring wheat cultivars was significantly lower than in the low RS cultivars.The promoter of SBEⅡ a gene from ten spring wheat cultivars was 2896 bp,The sequence analysis showed that the promoter region of SBEⅡ a genes from different spring wheat cultivars reached 99.92% similarity with AY357072.1.The results indicated that there were little allelic sites mutation,and only single-base mutation,Indel or insert in a single spring wheat cultivar.As a result,the promoter of SBEⅡ a gene might not cause the different relative expression level of SBE a gene in different spring wheat cultivars.