大豆凝集素基因lec-s转化烟草>增强对烟草花叶病毒的抗性

 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。

Enhanced resistance to Tobacco mosaic virus in transgenic tobacoo plants with lec-s from soybean

The lec-s gene encoding soybean lectin was inserted into transgenic vector pBI121. The leaf discs from tobacco were transfected by Agrobacterium tumefaciens strain EHA105/ pBI121:: lec-s. Kanamycin-resistant transformed plants were obtained. PCR and RT-PCR analyses confirmed successful integration of the foreign gene into the genome of the T₁ generation tobacco plants. Bioassays revealed that the resistance of transgenic plants to Tobacco mosaic virus (TMV) was increased; lesion numbers on leaves caused by TMV were markedly reduced in transgenic plants comparing with the controls. Quantitative RT-PCR analysis indicated that four defense-related genes, PR-1a, GST1, Pal, and hsr515, were up-regulated in transgenic lines inoculated with TMV. The up-regulations of these defense-relate genes were not observed in leaves of control plant after inoculation. The results suggested that lec-s gene might play a role in the regulation of plant defense responses through the induction of downstream defense-related genes after the recognition of microbial pathogens, thus the transformed tobacco plants with lec-s gene could enhance the resistance to TMV.