Soybean (Glycine max) is an economically important leguminous crop affected by bacterial pustule disease caused by Xanthomonas campestris pv. glycine max. Sustainable microbial approaches have gained importance due to increasing concerns associated with chemical pesticides and environmental contamination. The present study evaluated the antimicrobial activity, compatibility, plant growth–promoting potential, and preliminary alginate-based formulation of Pseudomonas putida and Lactobacillus plantarum for soybean biopriming applications. Antimicrobial activity was assessed using cross streak and agar cup assays employing cell-free supernatant (CFS) and neutralized cell-free supernatant (nCFS). Compatibility between the isolates was evaluated using perpendicular streak and spot assay methods. Preliminary carrier formulation studies were conducted using alginate as a carrier matrix followed by viability assessment and seed coating studies. Pseudomonas putida exhibited clear antagonistic activity against Xanthomonas campestris with a zone of inhibition of 15.3 ± 0.3 mm, whereas Lactobacillus plantarum showed minimal antagonistic activity. Compatibility studies demonstrated partial antagonistic interaction under direct contact conditions. Alginate at 1.5% (w/v) was found suitable for seed coating and imbibition. Viability studies demonstrated comparatively higher survival in mixed inoculum formulations. Both isolates showed positive indole-3-acetic acid (IAA) production, indicating their plant growth–promoting potential. The findings suggest that alginate-mediated microbial biopriming may serve as a promising eco-friendly strategy for soybean disease management and growth promotion.
Dasari et al. (Thu,) studied this question.