Bakanae disease caused by Fusarium fujikuroi is veryimportant 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. fujikuroiin vitro. Culture filtrate and
antibiotics from these isolates inhibited growth of the
pathogen. Two genes from seven gene locus of
phenazine were cloned in Escherichia coli DH5α.