Indigenous salt-tolerant rhizobacterium Pantoea dispersa (PSB3) reduces sodium uptake and mitigates the effects of salt stress on growth and yield of chickpea

摘要

Salt stress has multiple damaging effects on plants including physiological damage, reduced growth, and productivity. Plant growth-promoting rhizobacteria (PGPR) are one of the valuable options to mitigate the negative effects of this stress. In the present study, native bacteria from chickpea's rhizosphere were isolated, and checked for their salt tolerance and plant growth-promoting attributes (phosphate (P) solubilization, siderophores, indole-3-acetic acid (IAA) production, and 1-aminocyclopropane-1-carboxylate (ACC) deaminase production). One isolate, subsequently identified as Pantoea dispersa, showed appreciable production of IAA (218.3 mu g/ ml) and siderophores (60.33% SU), P-solubilization (3.64 mu g/ ml) and ACC deaminase activity (207.45 nmol/ mg/ h) in the presence of 150 mM NaCl, under laboratory conditions. Salt stress in uninoculated chickpea (GPF2 cultivar) plants induced high accumulation of Na+ ions (3.86 mg g(-1) dw) in the leaves, along with significant reduction in K+ uptake, membrane integrity, chlorophyll concentration, and leaf water content, thus resulting in impaired growth of the plant and yield (pods and seeds) in a salt concentration-dependent manner. The damage due to salt stress was restored significantly in plants inoculated with P. dispersa. A significant improvement in biomass (32-34%), pods number (31-34.5%), seeds number (32-35.7%), pods weight (30-32.6%), and seeds weight (27-35%) per plant occurred in salt stress-affected plants, which was associated with significant reduction in Na+ uptake, reduced membrane damage, significantly improved leaf water content, chlorophyll content, and K+ uptake. This study suggests for the first time that native P. dispersa strain PSB3 can be used to alleviate the negative effects of salt stress on chickpea plants and holds the potential to be used as a biofertilizer.