Abstract

Bakanae disease caused by Fusarium fujikuroi is very important in rice.Pseudomonas fluorescens produces a broad-spectrum antibiotic phenazine-carboxylic acid (PCA), which is active against a variety of fungal root pathogens. In this study contaminated rice samples were collected from infected farms of Guilan. 238 bacteria were isolated from rhizosphere and the antagonistic ability of 12 of them was demonstrated with two culture method. Eight of these isolates were identified as P. fluorescens. The effects of volatile metabolites produced by antagonistic P. fluorescens found in the isolates inhibited growth of F. fujikuroi in vitro. Culture filtrate and antibiotics from these isolates inhibited growth of the pathogen. Two genes from seven gene locus of phenazine were cloned inEscherichia coli DH5α.

Key words: Fusarium fujikuroi, Bakanae disease, Pseudomonas fluorescensphenazine-carboxylic acid, rice.