Osmolyte accumulation in moderately halophilic bacteria improves salt tolerance of chickpea

摘要

Salinity results in poor crop yield round the globe. We hypothesized those strategies of endogenous osmolytes proline, glycine betaine and choline accumulation in moderately halophilic bacterial strains Staphylococcus haemolyticus (ST-9) and Bacillus subtilis RH-4 isolated from saline rhizosphere have a role in improving bacterial and plant growth by alleviating salt stress. We checked the effect of varying salt stress (0, 0.5, 1, 1.5, 2, 2.5 M NaCl) on bacterial growth and osmolyte accumulation. The data showed that bacterial growth was affected by increasing salt stress however, cells cultured in the presence of 1.5 M NaCl stress showed higher accumulation of osmolytes. Seeds of Cicer arietinum Var. CM 98 were inoculated and grown up to full maturity at different salinity levels (0, 50, 100, 200 mM NaCl) in wire house under full sunlight. Inoculated plants showed significantly improved plant growth (germination, length, chlorophyll contents, total soluble sugars and protein content) and accumulation of endogenous osmolytes at 200 mM NaCl stress as compared to uninoculated control plants. We concluded that increased osmolyte accumulation can overturn the negative effects of high osmolarity in bacteria and plants. Both strains can be effectively used as bio inoculants for improving Cicer arietinum Var. CM98 growth under salt stress.