Biocontrol potential of Pseudomonas syringae against Emerging Phyto-Fungal Pathogens

Muhammad Jarrar Ahmed, Amna Shoaib, Qudsia Fatima and Barizah Malik

https://doi.org/10.22194/Pdc/3.1039

Fungal diseases caused by soil-borne pathogens like Macrophomina phaseolina, Fusarium oxysporum f. sp. lycopersici and Sclerotium rolfsii result in huge losses of crops including cereals, pulses, vegetables etc. hence threatening global food security. Bacterial biological control agents, such as strains of Pseudomonas, Bacillus, and Streptomyces, have been historically and currently utilized to manage soil-borne pathogens as eco-friendly alternatives in the quest for a sustainable solution.The antifungal potential of Pseudomonas syringae was assessed against the said phytopathogenic fungi through dual plate assay. The effect of bacterial metabolites was also assessed on the growth, biomass, and biochemical traits [total protein content (TPP), activity of catalase (CAT), peroxidase (POX), and polyphenol oxidase (PPO)] of the fungi. P. syringae significantly (p ≤ 0.05) inhibited the growth of M. phaseolina, S. rolfsii, and F. oxysporum f. sp. lycopersici by 80, 75, and 48%, respectively, in the dual culture assays. The various concentrations of bacterial metabolites (2, 4, 6, 8, 10, ---- 20%) significantly (p ≤ 0.05) suppressed the pathogens in a dose-dependent manner. Therefore, the biomass production of either M. phaseolina or S. rolfsii declined considerably by 65-100% with the increasing metabolite concentration from 2 to 10%, while for F. oxysporum f. sp. lycopersici, the biomass decreased by 50-100% with the concentration of 2 to16%. Inhibition in biomass production increased stress levels in the fungal cell, as indicated by enhancement in the biochemical enzymatic activity in the fungi. The study demonstrates that P. syringae effectively inhibits the growth of M. phaseolina, S. rolfsii, and F. oxysporum f. sp. lycopersici. These findings support the potential of P. syringae as an eco-friendly alternative to chemical fungicides, promoting sustainable agriculture by enhancing crop resilience and yield. Further research should focus on identifying the specific antifungal compounds in P. syringae metabolites responsible for this activity