Rabbit defensin NP-1 is one of the defensins showed the broadest spectrum of antimicrobial and strong antibacterial activity, which was isolated initially from polymorphonuclear neutrophils cells of rabbit. In order to improve the disease resistance of tobacco NC89, a recombinant plasmid named pBIC-35SNPl was transformed into a tobacco cultivar NC89 by Agrobacterium-mediated method. Transgenic tobacco plants have been selected on MS medium supplemented with kalamycin (100 mg/l), carbenicillin (500 mg/l), 6-benzylaminopurine (2.0 mg/l), and naphthylacteticacid (0.2 mg/l). PCR analysis, Southern Blot analysis, Western Blot analysis, and resistance tests confirmed the integration of NP-1 gene into tobacco genome. PCR amplified a 120 bp specific fragment corresponds to the expected size of amplified fragment. Southern Blot analysis confirmed the integration of 2.3 kb NP-1 gene, and Western Blot analysis detected the presence of 7.8 KD protein. It was showed that rabbit defensin gene NP-1 was integrated into the tobacco genome and expressed normally in transgenic tobacco plants. The antibacterial test showed the resistance to E. coli and soft rot bacteria, which have made significant progress in tobacco disease resistance and breeding.
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