外源基因在转基因马铃薯植株中的异常表达

Abnormal expression of foreign genes in transgenic Solanum tuberosum

根癌农杆菌感染马铃薯叶盘伤口细胞并进行共培养转化，感染叶盘在筛选培养基上可获得卡那霉素抗性的转化愈伤组织，并在转化细胞中检测到了NPTⅡ酶活性．在两种分化培养基上转化愈伤组织的分化率分别为17％和20％．DNA分子杂交证实了双向载体质粒pPZH1上的nptⅡ基因和zein－HEAAE融合基因均已导入并整合到马铃薯再生植株基因组中，导入的外源基因引起了转基因气生块茎中氨基酸组分的变化，大多数氨基酸含量有不同程度的提高，总氨基酸含量增加了96．1％；分子杂交与氨基酸分析结果表明转基因植株中外源zein－HEAAE基因的表达可能受到修饰．

Transformed calli were produced on the wounded edges of potato leaf discs 35days after infection by Agrobacterium on kanamycin selective MS medium. Neomycin phosphotransferase activities were detected in the transformed cells. The regeneration frequencies of transformed calli in two differentiation media were 17 % and 20%, respectively. The integration of npt Ⅱand zein-HEAAE genes within the T-DNA of binary plasmid PPZH1 into potato genome were confirmed by DNA hybridization. Amino acid contents of transgenic mlcrotubers were increased in various extents on their expression. with a total of 96. 1% over the control. The results of DNA hybridization and amino acid assay suggested that the expression of the foreign zein-HEAAE fusion gene in the transgenic potato had probably been suppressed.