中文摘要：

颗粒结合淀粉合成酶（GBSS）与可溶性淀粉合成酶（SSS）是淀粉合成的关键酶，其活性大小直接影响着淀粉的直链淀粉／支链淀粉比例、淀粉链长及结构等，进而影响淀粉品质。利用blast及分子生物学软件DNAStar对gbss、ssⅡ和ssⅢ基因的cDNA序列同源性进行分析比较，选用加船的261bp（1～261），ssⅢ的244bp（2164～2407），ssⅡ的281bp（161～441）的cDNA片段，并应用重叠PCR法将其拼接成一融合基因gbs3s2，构建了以CaMV 35S启动子驱动的含有“正向gbs3s2融合片段-pdk内含子-反向gbs3s2融合片段”ihRNAi的植物表达载体，为培育糊化温度低的马铃薯品系奠定基础。

英文摘要：

Granule-bound starch synthase and soluble starch synthase are the key enzymes in starch synthesis. Their activity would decide starch quality via affecting the chain length, the ratio of amylose content to amylopectin and the structure of starch. Performing homology analysis on gbss, ssⅡ and ssⅢ with software Blast and DNAStar followed by using 261 bp fragments from gbss（ 1 -261 ） , 244bp fragments from ss Ⅲ （2164 -2407 ） and 281 bp fragments from ss Ⅱ （ 161 -441 ）to make the fusion gene gbs3s2 with overlap PCR. Then the promoter CaMV 35S driven, containing ＇forward gbs3s2 fusion fragments - reverse pdk intron - reverse gbs3s2 fusion fragments＇, plant siRNA expression vector weve constructed, which lay the foundation for breeding a low gelatinization temperature potato.