Mycorrhiza colonization can induce qualitative and quantitative changes in the microbial community. The mechanisms which control interactions between bacteria and AM fungi in plant roots can be synergistic, competitive or antagonistic. In this study, biological and molecular studies indicated a competitive and antagonistic interactions between G. intraradices, Pseudomonas and Bacillus. In inoculated plants by beneficial microbial agents, plant immunity system sat in priming position and resistance pathways activated systemically and more effective in rice plants by pathogen infection. Treatments including, B. subtilis and B. subtilis+P. fluorescens, exhibited disease severity (DS) score less than 1.5, were considered resistant to infection by M. oryzae. Like MIR, rhizobacteria mediated ISR is mainly effective against necrotrophic pathogens and is based on priming of JA-regulated responses. This is the first study to evaluate the interaction between AMF and bacteria in rice plant, therefore rice as a monocotyledonous plant, could be a suitable host for studying the mechanisms and interactions between AM fungi and other microbial agents.
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