Adaptation of Enterobacter sp. to herbicides is correlated with distinct patterns of quorum sensing molecules

In this study, we employed a model that examined bacterial response systems in an artificial environment with wash water from the packaging of several pesticides, and no nutrient supplementation, allowing for the investigation of quorum sensing (QS) signaling molecules produced by a Enterobacter strain isolated from this environment. The herbicide saflufenacil, which was present at the isolation site, and glyphosate, which was absent, were utilized as stress agents in an in vitro system to evaluate the biofilm formation. These adaptive mechanisms are regulated by QS, which orchestrates collective behaviors within bacterial communities and initiates stress responses through the release of autoinducer molecules. The QS signaling molecules C6-HSL, C7-HSL, and C8-HSL were analyzed using liquid chromatography coupled with mass spectrometry; these molecules are primarily involved in biofilm maturation, biofilm formation, and protection against oxidative stress, respectively. Notably, the biofilm formation exhibited two distinct strategies in Enterobacter sp. CMA55A. One strategy, likely coordinated by the three QS molecules, was associated with the presence of saflufenacil in the culture medium, at concentrations presumably similar to those at the strain's isolation site. The second strategy, without these QS coordination, was observed in response to glyphosate and the highest concentration of saflufenacil, conditions not present at the isolation site. Future comparative genomic and transcriptomic studies may provide insights into these plastic responses and facilitate the exploration of potential applications in the bioremediation of various xenobiotics at differing concentrations in contaminated ecosystems.