Plant Stress (Jun 2024)
Exploring the impact of endophytic bacteria on mitigating salinity stress in Solanum lycopersicum L.
Abstract
In the era of climate change, plants are being compelled to adapt and endure progressively in unfavorable environments. Applying biostimulants to plants can improve their growth and resilience by mitigating the adverse effects of abiotic stresses. Endophytes are well-known for promoting plant growth and producing natural compounds. The current study focuses on the ability of endophytic bacteria to increase plant growth and reduce salt stress in tomato plants. Nine isolates from the stems of Fagonia indica and Ajuga bracteosa showed a variety of salt stress tolerances as well as solubilizing phosphate, indole acetic acid, ammonia production, siderophore production, and extracellular enzymes like protease, cellulase, and chitinase. Four Endophytic bacteria Enterobacter hormaechei (MOSEL-FLS1), Stenotrophomonas maltophilia (MOSEL-FLS2), Bacillus subtilis (MOSEL-S8), and Staphylococcus epidermidis (MOSEL-S9) were selected based on plant growth promoting traits and halotolerant assay. These endophytic bacteria were subjected to ex-situ activities to figure out their capacity to stimulate the growth of the tomato plant in the growth room under different concentrations of NaCl (50–200 mM). All bacterial strains stimulated tomato plant growth under salinity stress compared to uninoculated controls. Antioxidant enzymes (SOD and POD), chlorophyll, and proline level in the plants was increased after salt treatment. Moreover, the activity of antioxidant enzymes and their relative transcript levels were dependent on the concentration of salinity stress. These findings highlight the varied microbial community linked to medicinal plants and their capacity to promote plant growth, potentially mitigating salt stress through the regulation of osmolytes and antioxidant enzymes. This makes them promising contenders for biofertilizers.
