ارزيابي امكان كنترل بيولوژيكي قارچ Ophiostoma novo-ulmi (عامل بيماري مرگ هلندي نارون) توسط Bacillus subtilis در شرايط آزمايشگاهي

The Evaluation of biological control potential of Ophiostoma novo-ulmi, causal agent of "Dutch Elm Disease" by Bacillus subtilis in vitro

Bacteria play important role for biological control of plant disease. Bacillus spp. as; extensive existence in environment, tolerancc of high temperature and formation of resistant spores, are important and safe for biological control. Recent findings about the existence of this bacterium as endophyte trough plant vessel such as maple have opened a new horizon in order using of this bacteria for biological control of vascular diseases. Antagonistic effect of three isolates of Bacillus subtilis on Ophiostoma novo-ulmi, the causal agent of Dutch elm disease, was studied in vitro. Antibiosis of antagonistic mechanism as: volatile metabolites and culture filtrate was evaluated. Microscopic studies indicated that all of Bacillus isolates by production of antifungal metabolites caused growth inhibition and deformation of mycelium of causal agent. All isolates could produce antifungal volatile metabolites and growth inhibitors in PDA which decreased mycelial growth and spores germination of the fungus significantly. In most experiments, isolate B7 was better than other isolates in antagonistic activity. Potential of using Bacillus subtilis isolates for biological control against causal agent of Dutch elm disease is discussed.