Wheat (Triticum aestivum L.) is the second most important crop worldwide. However, its production faces significant challenges in saline environments. It is crucial to develop sustainable strategies to enhance wheat tolerance to salt stress. This study aimed to isolate rhizospheric bacteria from sea barley (Hordeum marinum) thriving in the salinity conditions within the Breede River District near Matjiesrivier (33°14'00.7"S 19°40'45.2"E), South Africa, and evaluate their potential to improve salt tolerance in wheat.
Several wheat genotypes were screened in our laboratory to identify the most tolerant and most sensitive genotypes. In this study, 25 rhizospheric bacteria were isolated from Hordeum marinum and screened for salt tolerance. Bacillus safensis, Microbacterium liquefaciens, Paenarthrobacter nitroguajacolicus, Arthrobacter globiformis, and Pseudarthrobacter sulfonivorans demonstrated the highest tolerance. These isolates were evaluated for enhancing salt tolerance in wheat seedlings under 100 mM NaCl. Bacillus safensis, exhibited the most pronounced tolerance enhancement, was subjected to greenhouse trials to evaluate its ability to improve salt tolerance in the sensitive genotype at the Feekes 11.0 stage (Ripening) of development, compared to tolerant genotype without bacterial inoculation under similar stress conditions.
Significant improvement in the tolerance of the sensitive genotype was observed. Investigating ROS and osmolytes accumulation as well as antioxidant enzyme responses revealed associations between this improved tolerance and changes in antioxidant enzyme activities. This study highlights the potential of rhizospheric bacteria for enhancing wheat tolerance to salinity. Furthermore, these findings provide foundations for understanding the molecular mechanisms by which bacteria contribute to enhancing wheat tolerance to salt stress.