【摘要】 直链淀粉由于其独特的理化性质,在工业上有着广泛的应用.郭志鸿[1]等利用RNA干扰技术抑制马铃薯中两类淀粉分支酶亚基基因Sbe1和Sbe2的表达,有效提高了马铃薯的直链淀粉含量.本研究利用RNA干扰技术,构建马铃薯SBEⅠ(the ndogenesis starch branching enzymeⅠ)和SBEⅡ(the endogenesis starch branching enzymeⅡ)单基因以及SBEⅠ和SBEⅡ双基因的RNA干扰双元表达质粒载体.采用农杆菌介导法将重组基因转化马铃薯品种Désirée后,得到3个转化系列.分别对转基因马铃薯植株进行PCR鉴定,对转基因淀粉表观直链淀粉含量和凝胶化特性等性质进行分析.结果表明,利用RNA干扰技术单独抑制SBEⅠ或SBEⅡ基因的表达,不能提高直链淀粉含量,甚至会导致其含量降低.而当SBEⅠ和SBEⅡ基因表达同时受到抑制时,超过50%的转基因株系直链淀粉含量高于对照.转化株系表观直链淀粉的含量最高可达到49.1%,与对照(28.5%)相比提高了20.6%.更多还原

【Abstract】 Amylose is extensively used in industrial applications because of it’s unique physicochemical property.Zhihong Guo inhibted expression of two potato starch branching enzyme subunit genes Sbe1 and Sbe2 by using RNA interference technology,effectively improved the amylase content in potato. To develop transgenic potato plants with high-amylose starch in tubers,the endogenesis starch branching enzymeⅠ( SBEⅠ) and Ⅱ( SBEⅡ) genes were,single or simutaneously,targeted for RNA mediated gene silencing by expression of RNA interference genes in potato. In this study,RNA interference was used for gene inhibition of the starch branching enzymeⅠ( SBEⅠ) and Ⅱ( SBEⅡ) genes. Three SBE-RNA interference plasmids were constructed and transformed into potato cultivar Désirée. Three transformed series were obtained and analyzed by PCR. The level of silencing of SBEⅠ and SBEⅡin transgenic plants was investigated by analysis of apparent amylose content. The results showed that silencing of SBEⅠ or SBEⅡ alone had yielded a very low frequency of high-amylose lines,and even a reduction in amylose content in most of transgenic starches. However,production of high-amylose potato lines were be achieved by simultaneous inhibition of SBEⅠ and SBEⅡ. In this transgenic series,more than 50% of the transgenic lines showed that amylose content was higher than thire control. The highest amylose content in one line was 49. 1%,increasing20. 6% in comparison with untransformed starch ones( 28. 5%).更多还原