Biofilm formed by Hansschlegelia zhihuaiae S113 on root surface mitigates the toxicity of bensulfuron-methyl residues to maize. (1st January 2022)

• Record Type: Journal Article
• Authors: Zhang, Hao; Qian, Yingying; Fan, Dandan; Tian, Yanning; Huang, Xing
• Is Part Of: Environmental pollution. Volume 292:Part A(2022)
• Publication Date: 2022-01-01
• Subjects: Bensulfuron-methyl -- Hansschlegelia zhihuaiae S113 -- Root biofilm -- Damage elimination -- Bioremediation; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2021.118366
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Bensulfuron-methyl (BSM) residues in soil threaten the rotation of BSM-sensitive crops. Microbial biofilms formed on crop roots could improve the ability of microbes to survive and protect crop roots. However, the research on biofilms with the purpose of mitigating or even eliminating BSM damage to sensitive crops is very limited. In this study, one BSM-degrading bacterium, Hansschlegelia zhihuaiae S113, colonized maize roots by forming a biofilm. Root exudates were associated with increased BSM degradation efficiency with strain S113 in rhizosphere soil relative to bulk soil, so the interactions among BSM degradation, root exudates, and biofilms may provide a new approach for the BSM-contaminated soil bioremediation. Root exudates and their constituent organic acids, including fumaric acid, tartaric acid, and l -malic acid, enhanced biofilm formation with 13.0–22.2% increases, owing to the regulation of genes encoding proteins responsible for cell motility/chemotaxis ( fla/che cluster) and materials metabolism, thus promoting S113 population increases. Additionally, root exudates were also able to induce exopolysaccharide production to promote mature biofilm formation. Complete BSM degradation and healthy maize growth were found in BSM-contaminated rhizosphere soil treated with wild strain S113, compared to that treated with loss-of-function mutants ΔcheA -S113 (89.3%, without biofilm formation ability) and ΔsulE -S113 (22.1%, without degradation ability) or sterile water (10.7%, control). Furthermore, the biofilm mediated by organic acids, such as l -malic acid, exhibited a more favorable effect on BSM degradation and maize growth. These results showed that root exudates and their components (such as organic acids) can induce the biosynthesis of the biofilm to promote BSM degradation, emphasizing the contribution of root biofilm in reducing BSM damage to maize. Graphical abstract: Image 1 Highlights: Strain S113 can degrade BSM, but also forms a biofilm on maize root surface. Root exudates enhance S113 biofilm formation by different mechanisms. Adding L-malic acid to induce biofilm formation increases BSM bioremediation efficiency. Biofilm formation on roots by S113 promoted the elimination of BSM injury to maize.