Unveiling the potential of Loigolactobacillus coryniformis BCH-4 to ameliorate drought stress in Zea mays L.

Abstract

The lactic acid bacterial (LAB) species have proven multifaceted roles in sustainable agriculture due to their biologically safe nature, making them eco-friendly. However, their plant growth-improving mechanisms in stressed and non-stressed conditions are still under consideration. Thus, the current work has been planned to evaluate the drought tolerance potential and plant growth-promoting (PGP) traits of Loigolactobacillus coryniformis BCH-4 in Zea mays L. This bacterium was tolerant in the presence of 30% PEG. It also exhibited auxin synthesis, ammonia production, and phosphate solubilization potential. Based on these findings, a pot experiment was conducted with selected drought-tolerant maize seeds (Sawari Kashmir) and drought-sensitive seeds (Malka-2016), bioprimed with L. coryniformis under 2 water regimes; 100% field capacity (optimal watering condition) and 50% field capacity (a drought stress condition). Our results manifested an upsurge in maize growth, photosynthetic pigments, and nutrient uptake in bioprimed seeds under stressed conditions. Besides, biopriming considerably improved nitrate reductase levels alongside higher nitric oxide and hydrogen sulphide activity. This treatment also improved drought-induced oxidative stress tolerance in maize plants by promoting osmolytes and antioxidant activities. Further, the GC-MS analysis revealed various drought-tolerant metabolites, known to have plant growth-promoting potential i.e., 1-hexadecene, tetradecane, hexadecanoic acid, 15-methyl-, methyl ester, and hexadecane, produced by L. coryniformis. Remarkably, these metabolites synergistically improve maize growth and tolerate the drought. This study publicized an extensive variety of metabolites, produced by L. coryniformis liable for plant growth promotion and drought tolerance.