Multifaceted Role of Rhizospheric Bacteria in Enhancing Sugar Beet Growth through Biofilm Formation, Salt Stress Mitigation and Biocon-trol Potential

Plant growth promoting rhizobacteria (PGPR) are beneficial microbes that improve plant health through several mecha-nisms, including nutrient uptake, stress mitigation and pathogen suppression. This study was carried out for isolation and characterization of PGPR strains from the rhizosphere of salt-treated sugar beet (Beta vulgaris L.). Functional assays were performed to evaluate their ability to tolerate NaCl stress, produce ACC deaminase, secrete siderophores, form biofilms and solubilize phosphate. All 35 isolates survived in 1 M NaCl but only 7 were resistant to 2 M NaCl. ACC deaminase activity was observed in 91% of the isolates, while 57% produced siderophores. None of them showed the ability to sol-ubilize phosphate. Biofilm formation showed strain-specific variability. Using 16S rRNA sequencing, different genera were identified including Pseudomonas, Bacillus and Achromobacter. In antagonism assays against Rhizoctonia solani and Pseudomonas sp. strain 31 showed the strongest inhibition. The results underline the multifunctional role of PGPR in supporting sugar beet growth under salt stress and indicate its potential for sustainable agriculture.