Comparative genomic analysis and phenazine production of Pseudomonas chlororaphis, a plant growth-promoting rhizobacterium

Pseudomonas chlororaphis HT66, a plant growth-promoting rhizobacterium that produces phenazine-1-carboxamide with high yield, was compared with three genomic sequenced P. chlororaphis strains, GP72, 30-84 and O6. The genome sizes of four strains vary from 6.66 to 7.30 Mb. Comparisons of predicted coding sequences indicated 4833 conserved genes in 5869-6455 protein-encoding genes. Phylogenetic analysis showed that the four strains are closely related to each other. Its competitive colonization indicates that P. chlororaphis can adapt well to its environment. No virulence or virulence-related factor was found in P. chlororaphis. All of the four strains could synthesize antimicrobial metabolites including different phenazines and insecticidal protein FitD. Some genes related to the regulation of phenazine biosynthesis were detected among the four strains. It was shown that P. chlororaphis is a safe PGPR in agricultural application and could also be used to produce some phenazine antibiotics with high-yield.