Thriving against the odds: Exploring halotolerant rhizobacteria in the saline rhizosphere of Tuzla lagoon's halophytes

Abstract

Soil salinization poses a significant threat to global crop production, affecting around 20% of agricultural fields with the challenges of osmotic and ionic stress. The reclamation of salinity-affected agricultural lands is a pressing concern. To bridge existing gaps in our understanding of halotolerant plant growth-promoting rhizobacteria (PGPR), this research strategically focuses on isolating and characterizing these beneficial bacteria from the rhizosphere of halophytes in the Tuzla lagoon area. The objective is to contribute essential insights, fostering a deeper understanding of halotolerant PGPR for application in sustainable agricultural practices, particularly in alleviating salinity-induced stress in plants.All nine isolates demonstrated remarkable abilities, including the synthesis of siderophores, with isolates B15, C20, E2, and H9 showcasing phosphate solubilization. Additionally, isolates E2 and H9 displayed phytase production, and five isolates exhibited indole acetic acid synthesis. Although 1-aminocyclopropane-1-carboxylate deaminase production was absent, hydrogen cyanide synthesis was evident in all isolates except H9. Isolate E2 did not demonstrate cellulase synthesis, but biofilm formation was observed in all isolates except C23.To assess the salinity stress mitigation potential of the isolates, a randomized complete block design bioassay was conducted with ten treatments (nine bacterial isolates and a control) across four salt concentrations (0 mM, 100 mM, 200 mM, and 300 mM). While the isolates successfully demonstrated multiple plant growth-promoting traits, their capacity to significantly alleviate the effects of salinity stress on wheat plants suggests the need for further exploration. Comprehensive greenhouse/field trials under diverse physiological and environmental conditions are recommended to unlock the full potential of these isolates in effectively mitigating salinity stress in crops.