Root rot caused by Macrophomina phaseolina poses a significant threat to black gram (Vigna mungo) production in India. This study aimed to isolate and evaluate antagonistic bacterial isolates from the rhizosphere of various trees in Gujarat for their biocontrol potential against M. phaseolina. Twelve bacterial isolates were screened in vitro, with five exhibiting over 70% mycelial growth inhibition. Among these, Pseudomonas aeruginosa (AF 4) showed the highest antagonistic activity. Seed biopriming with these isolates under pot conditions significantly improved seed germination, seedling vigour and reduced mortality. Biochemical assays revealed enhanced total phenol and peroxidase activities in bacterial-treated plants, peaking at 45 days after sowing, indicating activation of plant defense mechanisms. A significant negative correlation was observed between peroxidase activity and seedling mortality. These findings suggest that antagonistic bacteria, particularly P. aeruginosa (AF 4), can serve as effective and eco-friendly biocontrol agents against M. phaseolina in black gram

Biopriming, Black gram, Macrophomina phaseolina, Antagonistic bacteria, Peroxidase, Total phenol, Disease suppression

Seed biopriming with antagonistic bacterial isolates significantly improved plant growth and suppressed root rot caused by M. phaseolina in black gram. Pseudomonas aeruginosa (AF 4) was the most effective, promoting germination, vigour and biochemical defense activation. This approach offers a promising, sustainable alternative to chemical fungicides

Prajapati M.D., Patel H.H., Kandoriya P.J., Joshi R.L. and Chaudhari A.K. (2025). Antipathogenic Activity of Antagonistic Bacterial Isolates Against Macrophomina phaseolina and their Role in Inducing Biochemical Defence in Black Gram under Pot Conditions. Biological Forum, 17(7): 102-108