Study of the antagonistic properties of bacterial strains selected from the rhizosphere of halophytic plants

Saline soils pose a serious obstacle to agricultural productivity by restricting plant growth and increasing vulnerability to pathogenic infections. However, microorganisms associated with halophytic plant species offer promising avenues for improving plant resilience and providing biological control against fungal pathogens. This study focused on evaluating rhizosphere bacterial isolates collected from halophyte species in the Aral Sea region for their antifungal effectiveness and plant growth-promoting potential under saline conditions. From an initial pool of 70 pure bacterial cultures, 22 were selected and screened for antagonistic activity against Fusarium oxysporum f.sp. vasinfectum and F. graminearum on potato dextrose agar. All tested strains exhibited varying levels of fungal inhibition. Among them, eight strains showed strong potential, and five—designated as 4, 5, 10, 30, and 34.1—significantly enhanced root development in wheat and cotton. These isolates also contributed to increased salt tolerance, as evidenced by improvements in chlorophyll fluorescence and the efficiency of photosystem II. Subsequent assays revealed that these strains also exhibited antagonistic effects against additional fungal pathogens, including F. solani, F. culmorum, and F. tricinctum. Overall, the findings underscore the potential of rhizobacteria derived from halophytic ecosystems to serve as eco-friendly biocontrol agents and biofertilizers in salt-affected agricultural systems.