Antagonistic Potential of Mycorrhiza Associated Pseudomonas Putida against Soil Borne Fungal Pathogens

Mycorrhizal spores were found to be closely associated with bacteria on their spore wall surface known as mycorrhiza associated bacteria (MAB) and its play a major role in the plant growth promotion by production of many known and unknown metabolites, nutrient solubilization and suppression of many soil borne pathogens in rhizosphere of crop plants. The present study was carried out to understand the antagonistic potential of mycorrhiza associated bacterium i.e. Pseudomonas putida (Genbank Accession number HM590707) against selected soil borne fungal pathogens viz., Fusarium oxysporum, Ceratocystis fimbriata and Sclerotium rolfsii. The bacterium P. putida used in this experiment was isolated from Glomus mosseae spore. The antifungal properties of P. putida indicated that this bacterium could produce siderophores, ammonia, hydrogen cyanide (HCN), protease, chitinase, urease and ACC deaminase. The dual culture assay revealed that the P. putida found to inhibit 65.5, 68.8 and 62.2 per cent mycelial growth of F. oxysporum, C. fimbriata and S. rolfsii respectively under in vitro condition, which indicates the broad spectrum antagonistic activity of this bacterium. Similarly, it was observed that P. putida could suppress 58.8-61.1 per cent fungal biomass in liquid broth culture. This finding reveals the broad spectrum anti-fungal activity coupled with the production of anti-fungal metabolites of mycorrhiza associated P. putida can be explored as biocontrol agent for managing soil borne fungal pathogens under field condition.