[Construction of gene knock-out system for Paenibacillus polymyxa SC2].

To construct an efficient gene knock-out system for Paenibacillus polymyxa SC2.Temperature sensitive plasmid pRN5101 was transformed into P. polymyxa SC2 by electrotransformation. A mutant SC2-E was obtained, in which pmxE was disrupted by homologous recombination. To confirm whether pmxE was knocked out, we used antibacterial activity assay and high performance liquid chromatography to analyze the ability of mutants synthesizing polymyxin.We developed an efficient gene knock-out system for P. polymyxa SC2. Plasmid of pRN5101 could replicate at 28 degrees C and suicide at 39 degrees C in SC2. Mutants lost the ability of synthesizing polymyxin, indicating that pmxE gene was successfully knocked out.The constructed gene knock-out system for P. polymyxa provides a high-efficiency tool to detect genes function for P. polymyxa.