Production Tobacco Resistance To Bacterial Wilt Caused By Ralstonia Solanacearum Through Expressing A Quorum-Quenching Gene Attm In Transgenic Plants

Tobacco is one of the most important economic crop in our country. Tobacco bacterial wilt is a typical vascular disease caused by bacterium Ralstonia solanacearum. The bacterium invades plants from roots and damages the transport tissue in vascular through proliferation and a series of biochemical action, causing the plants dehydrated. Plants are hardly alive in case infected by the disease occurs. Tobacco bacterial wilt has become a serious disease affecting the yield and quality of tobacco.AHLs (N-acyl homoserine lactones), quorum-sensing signals regulate virulence gene expression in a range of plant and animal (including human) bacterial pathogens. However, AHL-inactivation approach can attenuate the plant pathogenicity of pathogens.In this research, the attM gene was transferred into tobacco, and the resistance to Ralstonia solanacearum of transgenic tobacco was tested, which can be the base for enhancing the baterial wilt resistance through transferring the QS quenching related genes into plants. The results are as follows:â‘ The attM gene was obtained by PCR amplification from Agrobacterium tumefaciens, and jointed to the pBI121 vector to construct the transformation vector. The Agrobacterium tumefaciens EHA105 was transformated by the pBI-attM through freeze-thaw method. Positive clones were tested by the restriction enzyme digestion and clonal PCR, and picked for the tobacco tranformation.â‘¡The tobacco was trasformated by leaf disc transformation method, which was mediated by the Agrobacterium tumefaciens EHA105 containinng the pBI-attM plasmid. Callus alive were numbered and Vegetative propagated. The seedlings from each lines were tested by PCR, PCR-Southern, RT-PCR, qPCR, GUS staining, and ELISA. All the results indicated that the attM gene integrated to the genome of tobacco and highly expressed in each lines.â‘¢The resistance to Ralstonia solanacearum of tobacco transformation lines were tested in vivo and in vitro respectively, with the wild type and pBI121 vector transformated tobacco as controls. The results demonstrated that the resistance to bacterial wilt of the tobacco overexpressed attM enhanced significantly. In this report, the attM gene, which can quench the quorum-sensing of Ralstonia solanacearum and further increase the resistance to bacterial wilt, was transferred into tobacco,that was meaningful for bacterial wilt controling by transgenic ways.