Reducing the disease severity of Macrophomina phaseolina by Pseudomonas fluorescens in greenhouse conditions

Macrophomina phaseolina, the agent of charcoal rot, is one of the most important soil-borne diseases of common bean, which decreases its yield significantly. Its chemical control, not only causes environmental problems but also it is difficult and sometimes ineffective. Recently, researchers have focused on applying the biocontrol micro-organisms against plant diseases. Fluorescent pseudomonads by producing antibiotics, siderophore, hydrogen cyanide, and protease, are the most important biological control agents of plant diseases. In this research, for studying the biocontrol ability of Pseudomonas fluorescens strains against M. phaseolina, plants were infected by M. phaseolina, which were isolated from bean fields of Khoram-Abad. Virulence of fungal isolates was evaluated in the greenhouse, then a fungus with the highest pathogenicity was chosen for next. The biocontrol ability of 8 P. fluorescens strains, which have been proven as biocontrol agents of other plant pathogens against the fungal pathogen already, was examined in vitro by dual culture and antifungal activity of bacterial volatile and nonvolatile metabolites. P. fluorescent UTPf125, which significantly inhibited the pathogen growth more than others, was selected for greenhouse tests. Results showed that UTPf125 causes a significant increase in fresh and dry weight of the plant in the greenhouse in addition to decreasing the disease severity in root and crown of infected plants from 75% to 25%. All experiences have been done in 3 replications. Statistical analysis was performed using SAS ver.9.2 and Duncan test was used to show significant differences among treatments.

کلیدواژه ها:

Charcoal Rot ، Antibiotics ، Disease severity