Construction and Characterization of a ppbR gene Mutant of Pseudomonas sp. M18

Abstract:

Pseudomonas sp. M18, one of plant-growth-promoting rhizobacteria, can produce secondary metabolites including phenazine-1-carboxylic acid (PCA) and pyoluteorin (Plt). PA2572 gene coding protein is a probable two-component response regulator in Pseudomonas according to homologous speculations. In order to investigate its genetic function, PA2572 homologous gene, ppbR, was amplified from M18 genome, inactivated by inserting a Gm cassette. The resulting reconstruct was introduced into the M18 genome using homologous recombination technique, so as to obtain the null mutant M18P. The results showed that the M18P has less flagellar swimming and swarming motility, and yielded fewer PCA. The production of PCA was only 50% of the wild type. However, there was no remarkable difference between mutant and wild type in producing pyoluteorin in KMB medium.