Stress, Phages, and EPS: Factors That Enhance Bradyrhizobium Biofilm Formation
Year: 2026
Type: article
Abstract: Biofilms and their exopolysaccharide (EPS) matrix help soil rhizobia ride out stress, colonize roots, and ultimately succeed in symbiosis. We asked whether bacteriophages and common abiotic stressors modulate EPS-linked biofilm traits in Bradyrhizobium S3.9.2GM. Using a validated crystal violet (CV) microtiter assay for biomass and Congo Red (CR) colony phenotyping for matrix-linked traits, we found that phage and sublethal stressors (osmotic, oxidative, temperature shock) generally increased biofilm biomass, with the largest effects under combined phage + stress conditions. One-way ANOVA showed a strong treatment effect on OD570 (biofilm biomass; p < 0.001), while mucoid score and CR halo intensity trended upward in combined treatments but were not significant at α = 0.05. These patterns are consistent with literature showing stress-induced EPS in rhizobia and context-dependent phage–biofilm interactions, and they suggest that simultaneous biotic and abiotic pressures can amplify EPS-associated phenotypes in the rhizosphere.
Source: Berkeley Scientific Journal
DOI: 10.5070/bs3.69983
Author: Ziad Cohen
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
OpenAlex ID: W7224814091