Unveiling the biocontrol potential of Pseudomonas syringae through seed biopriming against charcoal rot disease in maize

In Punjab, Pakistan, maize production faces a significant threat from charcoal rot disease, caused by the soil-borne fungus Macrophomina phaseolina. To mitigate this issue and ensure food safety, researchers explored the potential of Pseudomonas syringae, a harmless gram-negative bacterium against charcoal rot disease in maize. Maize seeds treated with P. syringae (PS) were planted in soil containing the charcoal rot fungus in pot experiments. The outcome was then compared with the impact of NPK fertilizers and mancozeb fungicide. The positive control, with M. phaseolina alone, exhibited high disease severity resulting in a greater reduction of 30–70 % in the plant's biophysical and biochemical traits. Mancozeb, NPK, or PS, managed 66, 41, and 55 % of diseases and improved the biophysical and biochemical traits of the plants by up to 200 %. Applying P. syringae in combination with the recommended dose of NPK was found as the most promising treatment which significantly improved plant resistance by managing 90 % of disease through improving growth and biochemical traits (up to 300 %). This research suggests effective control of M. phaseolina by combining P. syringae with NPK, enhancing plant defense mechanisms and potentially improving pathogen-induced resistance in the maize plants.