بررسي برخي مكانيسم هاي بيو كنترل بيماري سوختگي غلاف برگ برنج (Rhizoctonia solani) بوسيله آنتاگونيست هاي باكتريايي در شرايط آزمايشگاهي

Study on some Mechanisms to Biocontrol rice sheath blight (Rhizoctonia solani) by antagonists bacteria in vitro

In a survey, conducted during 1999-2001, 184 bacterial isoletes were collected from rhizosphere of different rice fields. Among these, some strains with strong and promising antagonistic activities were selected for complementary srudies. According to morphological, biochemical, physiological characteristics, strains encoded 5.93 and T 42 were identified as Pseudomenas fluorescens, strain 24 as Bacillus cereus and strains 29 and 120 as B. subtilis. Regarding the mechanism of actions, all three strains of 5, 93, and T42 inhibited normal mycelial growth of the fungus through the production of some antibiotic and volatile metabolites under labratoary condition,. Whereas strains 24, 29 and 120 suppressed mycelial growth of R. solani by volatile metabolites. None of these strains (5, 93 & T42) produced siderophore on kingʹs B medium