摘要
分析了来源于农杆菌介导的4个独立的大豆转化系的后代遗传特性。分别采用种子切片GUS染色方法和除草剂涂抹以及喷洒方法检测gus报告基因和抗除草剂bar基因在后代的表达。其中3个转化系T1代gus基因和bar基因能够以孟德尔方式3:1连锁遗传,说明这2个基因整合在大豆基因组的同一位点。这3个转化系在T2代获得了纯合的转化系,并能够稳定遗传至T5代。有一个转化系在T1代GUS和抗除草剂检测都为阴性,但通过Southern杂交证明转基因存在于后代基因组,显示发生了转基因沉默。为了证明转基因沉默是转录水平还是转录后水平,T1代植物叶片接种大豆花叶病毒(SMV)并不能抑制转基因沉默,说明该转化系基因沉默可能不是发生在转录后水平。
Four transgenic soybean lines generated via Agrobacterium-mediated transformation were used to analyze inheritance of the transgenes. Seed chip GUS assay and herbicide leaf painting and spraying assays were applied to test the gus reporter gene and the herbicide resistant bar selectable marker gene, respectively. Three of the four transgenic soybean lines were stably inherited in a Mendelian fashion with co-segregation of both transgenes in a 3.＇1 segregation ratio in the T1 progeny, indicating that both transgenes were integrated into the same locus of the soybean genome. Homozygous transgenic progeny plants were obtained in the T2 generation of these lines, and the transgenes were inherited in five successive generations. However, in one transgenic line, all the T1 progeny plants showed GUS negative and herbicide sensitive. Southern blotting analysis confirmed that the transgenes were passed into the T1 progeny, indicating that the transgenes were both silenced. To test if the transgene silencing was due to transcriptional or post-transcriptional level, Soybean mosaic virus （SMV） was inoculated on leaf tissues of the T1 plants to test possible reverse effects on transgene silencing. Infection with SMV did not suppress transgene silencing, suggesting that transgene silencing in this transgenic line may not be due to post-transcriptional gene silencing.
关键词
转基因大豆
遗传分析
转基因沉默
SMV
transgenic soybean
inheritance analysis
transgene silencing
SMV
