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将编码大豆凝集素的lec-s基因插入植物表达载体pBI121中,构建植物重组表达质粒pBI121::lec-s。由根癌土壤杆菌EHA105介导的叶盘法转化烟草,获得了转基因烟草株系。PCR和RT-PCR检测证明lec-s基因已转入烟草植株中。接种烟草花叶病毒(Tobacco mosaic virus,TMV)进行抗病性试验结果表明,转基因烟草叶片上的病斑数显著减少,说明转基因烟草表现出对TMV的抗性。定量RT-PCR检测发现,接种TMV后,抗病防卫基因(PR-1a、GST1、Pal和hsr515)在转基因烟草叶片中显著上调表达。这些结果表明,大豆凝集素基因lec-s转化烟草可对TMV产生抗性,其作用机制可能在于lec-s基因参与了植物的防卫信号通路,诱导了抗病防卫基因在转基因植株体内的表达,增强了植株对TMV的系统抗性。
The lec-s gene encoding soybean agglutinin was inserted into the plant expression vector pBI121 to construct the plant recombinant expression plasmid pBI121 :: lec-s. Tobacco was transformed by leaf disc method mediated by Agrobacterium tumefaciens EHA105 to obtain a transgenic tobacco line. PCR and RT-PCR showed that the lec-s gene had been transferred into tobacco plants. Inoculation of tobacco mosaic virus (Tobacco mosaic virus, TMV) for disease resistance test results showed that the transgenic tobacco leaves significantly reduced the number of lesions, indicating that transgenic tobacco showed resistance to TMV. Quantitative RT-PCR analysis showed that the resistant defense genes (PR-1a, GST1, Pal and hsr515) were significantly up-regulated in transgenic tobacco leaves after inoculation of TMV. These results indicated that lec-s transformed tobacco could be resistant to TMV. The possible mechanism may lie in that lec-s is involved in the defense signaling pathway of plants and induces the expression of anti-disease defense genes in transgenic plants, Enhanced plant resistance to TMV.