Pseudomonas-Mediated Mitigation of Salt Stress and Growth Promotion in Glycine max

Abstract

In the present investigation we emphasized the role of plant growth-promoting bacterium to characterize activities of stress-associated enzymes, proline accumulation, chlorophyll estimation, and Na+/K+ ratio in Glycine max L. Merrill under salt stress. The results showed that inoculation of plants with Pseudomonas koreensis strain AK-1 (MTCC no. 12058) grown under salt treatment induced growth promotion, reduced Na+ levels but increased K+ levels in leaves and roots in comparison with the non-inoculated salt-treated plants. Correspondingly, inoculation of soil with bacterium treated with NaCl plants maintained a lower ratio of [Na+]/[K+] in NaCl-stressed plants. The experiment designed in a completely randomized manner which consisted of four treatments comprising of bacterial inoculation with and without salt treatment including one absolute control (without inoculation and salt treatment). Inoculation of bacterial strains together with salt treatment showed significant increase in activity of stress enzymes along with proline content as compared to salt-treated plants. Application of 200 mM NaCl at 0 day after seeding results inadequate number of lateral roots in uninoculated plants as compared to strain AK-1-inoculated plants. Soybean plants not inoculated with strain AK-1 showed 33 % seed germination in salt-treated plants, and the plant growth was also significantly decreased compared to the strain AK-1-treated plants.