Arbuscular Mycorrhizal Fungi: A Biocontrol Agent against Common Bean Fusarium Root Rot Disease

Effectiveness of arbuscular mycorrhizal fungi in the protection of common bean plant (Phaseolus vulgaris L.) against Fusarium root rot disease was investigated in the present study under natural conditions in pot experiment. A mixture of arbuscular mycorrhizal fungi consists of propagated units of Glomus mosseae, Glomus intraradices, Glomus clarum, Gigaspora gigantea and Gigaspora margarita in suspension form (106 unit L-1 in concentration) was used at dilution of 5 ml L-1 water. The obtained results demonstrated that, arbuscular mycorrhizal colonization significantly reduced the percentage of disease severity and incidence in infected bean plants. On the other hand, mycorrhizal colonization significantly increased the tested growth parameters and mineral nutrient concentrations. While, infection with Fusarium root rot disease negatively affected on the mycorrhizal colonization level in bean roots. Finally, mycorrhizal colonization led to a significant increase in the phenolic content and the activities of the investigated defense related enzymes (Phenylalanine ammonia-lyase, polyphenol oxidase and peroxidase enzyme). From the obtained results, it can be concluded that the application of arbuscular mycorrhizal fungi as a biocontrol agent played an important role in plant resistance and exhibit greater potential to protect bean plants against the infection with F. solani.