Glyphosate effect on biofilms formation, mutagenesis and stress response of E. coli

Glyphosate is the most widely used herbicide in the world. There is still no complete clarity about the degree of its genotoxicity and mutagenicity. In addition, its effect on bacterial biofilms, the main life form of soil microbial communities, has not been adequately studied. Toxicity and mutagenicity, as well as changes in the bacterial biofilm biomass, physiological activity, and the number of living cells in its composition in the presence of glyphosate were assessed using the Escherichia coli model. To assess damage to cellular components under the action of this pesticide, luminescent whole-cell bacterial lux-biosensors were used. Changes in the level of mutagenesis were studied by the method of rifampicin mutants. High integral toxicity of glyphosate, the average level of increased oxidative stress and protein damage were shown with the help of bacterial biosensors. All the studied concentrations of the pesticide completely or partially suppress the matrix and structure of the E. coli CDC F-50 biofilm formation, as well as the bacterial cells metabolic activity in the biofilm. At the concentrations of 6.7 and 0.67 g/L, glyphosate suppresses mutagenesis, probably due to general suppression of metabolism, and at the concentration of 0.0067 g/L, it enhances mutagenesis by six times compared with the spontaneous level. Suppression of bacterial biofilms formation, toxic effects on microorganisms, and mutagenesis enhancement by glyphosate can lead to negative consequences for natural microbiomes.