عامل بيماري سوختگي غلاف برگ برنج )SHIZOCTONIA SOLANI( اثرات آنتي بيوزيس باكترهاي آنتاگونيست سواسازي شده از مزارع برنج استان گيلان روز قارچ

Effects of antibiosis antagonistic bacterial isolated from rice paddy of the Guilan province on the Rhizoctonia solani causal agent of rice sheath blight

Antibiosis effects of 37 bacterial antagonistic isolated from rice paddy of the Guilan province were surveyed in vitro in preventation of the vegetative growth of the causal agent rice sheath blight (Rhizoctonia solani). Antagonistic strains caused a large changes on the pathogen include lysis and fragmentation, vacuolation, shriveling and swelling hyphal tip in the dual culture on PDA medium. In the test of production of antifungal volatile metabolites, effect of 15R (Pseudomonas fluorescense bv. 5) strain was the best than other (%77.16) in prevention of vegetative growth of the causal agent. None of the 37 antagonistic strains reduced inhibition zone in the test of production of sideropfiore in the different concentrations of iron added to Kings B medium but among eight selective antagonistic strains, some strains increased the vegetative growth of the causal agent after removing bacteria and incubation in 60°C temperature on the King s 13 medium contained iron. In the test of extracellular exudates selective antagonistic strains in the different concentrations, effect of 133 (P. fluorescense bv. 5) strains in the %25 concentration was the best than other (47.50) in prevention of vegetative growth of the causal agent. Autoclaving (121 °C, l at.) extracellular exudates of selective antagonistic strains in the %25 concentration influenced on the their effects but this effect was little in prevention of vegetative growth of the causal agent by the extracellular exudates 23R (P. fluorescense bv. 5) strain.