A total of 30 Fluorescent Pseudomonads strains were isolated from citrus leaves, twigs and fruits in Kerman and Hormozgan provinces. Results of characterized phenotypic features showed two groups of strains namely including Pseudomonas fluorescens by. III and V, and P. putida by. B. Fatty acids determination using gas- liquid chromatography indicated 16 fatty acids for P. fluorescens strains and 13 fatty acids for P. putida strains.The main fatty acids for P. fluorescens strains were 10: 0 3- OH, 12:0, 12:0, 12:0 2-OH, 12: 3-OH, 16:0, 16:1 w7c and 17:0 cyclo and for P. putida strains were 10: 0 3-OH, 12:0, 12:0, 12:0 2-OH, 12: 3-OH, 16:0, 16:1 w7c, 17:0 cyclo and 19:0 cyclo w8c. Representative strains from both groups showed antagonistic activity towards Xanthomonas axonopodis pv. Citri, the causal agent of Asiatic citrus canker disease in petri plates. Application of some representative antagonist strains under greenhouse condition reduced number of disease lesions from 23.78% to 64%.
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