بررسی تاثیر استرین سودوموناس فلورسنت بر محتوای فنل کل گیاهچه‌ی لوبیا و کنترل بیولوژیک بیماری بو‌ته‌میری لوبیا ناشی از قارچ Rhizoctonia solani

Root rot disease caused by Rhizoctonia solani is an important disease in bean fields of Iran. The chemical control of this disease is ineffective because it’s a soil borne disease with a wide range of hosts and high aggressiveness. Using the biocontrol bacterial agents is one of the promising ways to overcome this disease. During the summer of 1394, infected plants by R. solani were collected from bean fields of Khomein and their fungal agents were isolated and identified. Virulence of fungal isolates was evaluated in greenhouse, then a fungus isolate with the highest pathogenicity was selected for next experiments. In this study, the biocontrol ability of eight bacterial strains of Pseudomonas fluorescens from biological control collections of the University of Tehran, against damping off and root rot of bean was examined in vitro by dual culture test, the antifungal activity of bacterial volatile and non-volatile metabolites on fungal pathogen. P. fluorescens P13, which was the most effective in controlling the pathogen in all experiments, was chosen for the next. Then its biocontrol ability in greenhouse conditions was investigated and its effect on plant defense system was evaluated by measuring plant total phenol compounds on 1, 3, 5, 7 and 9 days after inoculation with R. solani and P13. All experiments were performed in 4 replications. Statistical analysis andcomparison of mean traits were performed by using Duncan's multiple test and SAS ver 9.2 software. The results showed that until the 30th day after inoculation bean seedlings by pathogen and biocontrol agent, in comparison with control, P13 controlled the disease 67 percent. In infected soil by pathogen, the highest total phenol compounds was evaluated on the 9th day, While the highest total phenol compounds in P13 treatments in infected soil was measured on the 5th day after inoculation. The results showed that P13 strain increased plant resistance to the pathogen by increasing total phenol compounds.