Salinity-resistant plant growth promoting rhizobacteria ameliorates sodium chloride stress on tomato plants

Abstract

Salinity is one of the major anthropogenic as well as environmental stresses that reduce plant growth. Results show that even after being adapted up to 6% sodium chloride (NaCl) concentration, all selected isolates were able to solubilize phosphate, and produce phytohormones, siderophores and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase enzyme. NT1 was found to exhibit the highest phosphate solubilization zones (25 mm), siderophore production (1000 µg ml⁻¹) as well as ACC deaminase production (50 µMmg⁻¹h⁻¹) potential under laboratory conditions. On the other hand, pot studies conducted on tomato plants under 2% NaCl stress proved that C4 and T15 were the best growth promoters. C4 showed 50% enhancement in root and shoot length as compared to NaCl added untreated plants as well as in absence of NaCl. C4 also enhanced salinity tolerance in plants with the lowest uptake of NaCl thereby reducing the salt stress on plants. C5 enhanced biomass production in tomato plants with increased uptake of the salts by plants, thereby reducing the salt concentration in the soil. The study thus shows that the selected isolates can be used for the plant growth promotion of plants under salinity stress.

Keywords:

• plant growth promoting rhizobacteria (PGPR)
• 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase
• Atomic Absorption Spectrophotometer (AAS)
• salinity
• phytoremediation

Acknowledgements

Our sincere thanks go to UGC for providing us with the financial help for conducting this study. We also wish to thank the Head of the Department of Microbiology for allowing us to carry out this work at the department of Microbiology.