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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。
The genetic characteristics of progenies derived from Agrobacterium-mediated four independent soybean lines were analyzed. The expression of gus reporter gene and herbicide resistance bar gene in progenies were detected by seed section GUS staining, herbicide application and spraying methods, respectively. Three of the three lines, the T1 generation gus gene and the bar gene, were able to be linked by Mendel’s 3: 1 linkage, indicating that these two genes are integrated at the same site in the soybean genome. The three transformed lines obtained homozygous transformants in T2 generation and were able to inherit stably to T5 generation. One transformant line tested negative for both GUS and herbicide resistance at T1, but the presence of the transgene in the offspring genome was confirmed by Southern blotting and showed transgene silencing. In order to prove whether transgene silencing is transcriptional or posttranscriptional level, inoculation of soybean mosaic virus (SMV) on T1 plant leaves did not inhibit transgene silencing, indicating that transgene silencing may not occur at post-transcriptional level.