Isolation of salt-tolerant Pseudomonas strains with potential for alleviation of salt stress in peanut plant (Arachis hypogaea L.)

Plant growth-promoting rhizobacteria (PGPR) is a promising solution to improve plant growth under salt stress. Among PGPR, Pseudomonas is a genus of bacteria that possesses a variety of mechanisms in promoting plant growth and inducing resistance to biological as well as non-biological stress. This study aimed to isolate the genus Pseudomonas from the salty-contaminated rhizosphere of plant root collecting at Nam Dinh, and also investigate their functions in promoting the growth of peanut seedlings under salty conditions. Nine Pseudomonas bacteria were isolated, but only seven of them were identified by Pseudomonas-specific primers. Two of those seven isolates, ND06 and ND09, were chosen based on their characteristics in promoting plant growth such as the production of indole-3-acetic acid (IAA), phosphate solubilization, and nitrogen fixation. In addition, both two strains also carried the coding gene for 1-aminocyclopropane-1-carboxylate (ACC) deaminase which plays an important role in supporting plants to withstand various stress conditions. Especially, the ND09 strain improved the growth parameters of peanut seedlings under normal and salty stress conditions; while the ND06 only presented the plant growth enhancement under salty stress but not in normal conditions. These results suggest the ND09 strain may be used as a biological agent for eco-friendly agricultural practices in the future.