Abstract:
A halotolerant plant-growth-promoting rhizobacteria (PGPR) can ameliorate salt stress in associated plants by various mechanisms. Therefore, the present study aimed to characterize a PGPR Klebsiella sp. SBP-8 for its ability to tolerate salt stress and to study the mechanism of PGPR-mediated mitigation of salt stress in the wheat plant. The abiotic stressors result in multiple changes in the fatty acid composition of Klebsiella sp. SBP-8, helping the membrane to keep its integrity, fluidity, and function for its growth under salt (NaCl) stress conditions. The changes in fatty acid composition of test organism were analyzed by fatty acid methyl ester (FAME) analysis under varying saline conditions. The spectroscopy (GC-MS) profile of cell extract at different salt concentrations was comprised of hydrocarbons, and fatty alcohols with varying carbon chain length. Inoculation of Klebsiella sp. SBP-8 to wheat seedling showed increase in proline, total soluble sugar, and total protein content of treated plants. Bacterial inoculation also decreased the concentration of salinity-induced malondialdehyde (MDA) content. In addition, bacterial inoculation also increased the various antioxidative enzymes like superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX) in treated plants. It is likely that bacterial inoculation alleviated the salt stress to wheat plant by co-ordination of antioxidative machinery, and improvement in osmolyte contents. Therefore, the present study suggests that bacterial-inoculated wheat plants were able to cope better with salt stress than uninoculated control, therefore it can serve as a promising bio-inoculant for enhancing the growth of wheat like cereal crops under saline stress.