Seed priming with bacterial and fungal biocontrol agents alter physio-chemical parameters to suppress leaf rust disease in bread wheat

Wheat (Triticum aestivum L.), a staple crop in Pakistan and the third most cultivated crop globally suffers yield losses of up to 60-70% due to leaf rust (Puccinia triticina). This study explored sustainable management strategies using biocontrol agents (Trichoderma sp. and Bacillus sp.) by seed priming across four different wheat varieties i.e., Arooj-22, Subhani-21, Punjab-11, and Shafaq-06. The experiment was conducted using a Complete Randomized Block Design (RCBD). Morphological parameters, including fresh and dry shoot/root weights, spike length, number and weight of seeds per spike, yield per plant, 1000-grain weight, shoot/root length, plant height, leaf area, peduncle length and awn length were assessed alongside physiological parameters such as malondialdehyde (MDA), hydrogen peroxide (H₂O₂), glycine betaine, chlorophyll content and free proline levels. Statistical analysis (ANOVA and LSD at 5% probability) revealed that Subhani-21 primed with Trichoderma sp. exhibited the best results by demonstrating reduced oxidative stress (lower MDA and H₂O₂ levels) and improved chlorophyll, glycine betaine, and free proline levels. These results highlighted the potential of eco-friendly treatments to mitigate leaf rust stress and enhancement of wheat growth and productivity.