Cloning of phenazine carboxylic acid genes of Fusarium fujikuroi antagonists bacteria

Abstract

Bakanae disease caused by Fusarium fujikuroi is an important diseases on rice. Pseudomonas
fluorescens produces the broad-spectrum antibiotic phenazine-carboxylic acid (PCA), which is active
against a variety of fungal root pathogens. In this study two genes from seven gene locus of phenazine
were cloned in Escherichia coli DH5. The contaminated rice samples were collected from infected farms
of Guilan. 238 bacteria were isolated from the rhizosphere. The antagonistic ability of 12 of which, was
demonstrated with dual culture method. From the biochemical and culture results, 8 isolated were
identified as P. fluorescens. The two genes from seven gene locus of phenazine were cloned into E. coli
DH5. We speculate that P. fluorescens that produce 2,4-diacetylphloroglucinol (Phl) play an important
role in the natural suppressiveness of this soil to causal agent of collar and root rot of rice.