Morales-Olivares Manuel Isaac, Castrejón-Godínez María Luisa, Mussali-Galante Patricia, Tovar-Sánchez Efraín, Saldarriaga-Noreña Hugo Albeiro, Rodríguez Alexis
Programa de Doctorado en Ciencias Naturales, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, Cuernavaca 62209, Morelos, Mexico.
Facultad de Ciencias Biológicas, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, Cuernavaca 62209, Morelos, Mexico.
Microorganisms. 2025 Mar 13;13(3):651. doi: 10.3390/microorganisms13030651.
Herbicides are the most employed pesticides in agriculture worldwide; among them, glyphosate is the most successful herbicide molecule in history. The extensive use of glyphosate has been related to environmental pollution and toxic effects on non-target organisms. Effective remediation and treatment alternatives must be developed to reduce the environmental presence of glyphosate and its adverse effects. Bioremediation using microorganisms has been proposed as a feasible alternative for treating glyphosate pollution; due to this, identifying and characterizing microorganisms capable of biodegrading glyphosate is a key environmental task for the bioremediation of polluted sites by this herbicide. This study characterized the glyphosate resistance profile and degradation capacity of the bacterial strain CEIB S4-3. According to the results of the bacterial growth inhibition assays on agar plates, CEIB S4-3 can resist exposure to high concentrations of glyphosate, up to 1600 mg/L in glyphosate-based herbicide (GBH) formulation, and 12,000 mg/L of the analytical-grade molecule. In the inhibition assay in liquid media, CEIB S4-3 resisted glyphosate exposure to all concentrations evaluated (25-400 mg/L). After 48 h exposure, GBH caused important bacterial growth inhibition (>80%) at concentrations between 100 and 400 mg/L, while exposure to analytical-grade glyphosate caused bacterial growth inhibitions below 15% in all tested concentrations. Finally, this bacterial strain was capable of degrading 60% of the glyphosate supplemented to culture media (50 mg/L), when used as the sole carbon source, in twelve hours; moreover, CEIB S4-3 can also degrade the primary glyphosate degradation metabolite aminomethylphosphonic acid (AMPA). Genomic analysis revealed the presence of genes associated with the two reported metabolic pathways for glyphosate degradation, the sarcosine and AMPA pathways. This is the first report on the glyphosate degradation capacity and the genes related to its metabolism in a genus strain. The results from this investigation demonstrate that CEIB S4-3 exhibits significant potential for glyphosate biodegradation, suggesting its applicability in bioremediation strategies targeting this contaminant.
除草剂是全球农业中使用最为广泛的农药；其中，草甘膦是历史上最为成功的除草剂分子。草甘膦的广泛使用与环境污染以及对非靶标生物的毒性作用有关。必须开发有效的修复和处理方法，以减少环境中草甘膦的存在及其不利影响。利用微生物进行生物修复已被提议作为处理草甘膦污染的一种可行替代方法；因此，识别和表征能够降解草甘膦的微生物是通过这种除草剂对污染场地进行生物修复的一项关键环境任务。本研究对细菌菌株CEIB S4-3的草甘膦抗性谱和降解能力进行了表征。根据琼脂平板上细菌生长抑制试验的结果，CEIB S4-3能够抵抗高浓度草甘膦的暴露，在基于草甘膦的除草剂（GBH）制剂中可达1600 mg/L，在分析级分子中可达12000 mg/L。在液体培养基中的抑制试验中，CEIB S4-3对所有评估浓度（25-400 mg/L）的草甘膦暴露均具有抗性。暴露48小时后，GBH在100至400 mg/L的浓度下导致重要的细菌生长抑制（>80%），而暴露于分析级草甘膦在所有测试浓度下导致的细菌生长抑制低于15%。最后，当用作唯一碳源时，该细菌菌株能够在12小时内降解添加到培养基（50 mg/L）中的60%的草甘膦；此外，CEIB S4-3还能降解主要的草甘膦降解代谢产物氨基甲基膦酸（AMPA）。基因组分析揭示了与报道的两种草甘膦降解代谢途径（肌氨酸途径和AMPA途径）相关的基因的存在。这是关于某一属菌株中草甘膦降解能力及其代谢相关基因的首次报道。本研究结果表明，CEIB S4-3在草甘膦生物降解方面具有显著潜力，表明其在针对该污染物的生物修复策略中的适用性。
