Quorum sensing mediated adaptive strategies of anammox consortia to plasticizers: Metabolic patterns, cellular responses and antibiotic resistance gene transmission

The widespread use of antibiotics leads to large amounts of antibiotic residues in the environment, further accelerating the transfer of antibiotic resistance genes (ARGs). In addition to antibiotics, many non-antibiotic pollutants, such as nanomaterials, disinfectants, non-antibiotic pharmaceuticals and microplastics, have also been reported to drive the ARGs transmission. Phthalates are a common plastic additive that is continuously released and accumulated in the environment. Plasticizers-microorganism interactions have aroused growing environmental and ecological concerns. While it has been demonstrated that anammox consortia adapted to the non-antibiotic pollutants stress, potential community adaptation strategies have not been adequately addressed. In this study, it was found that the adaptation of anammox consortia mainly depended on microbial cooperation and molecular regulation. Initially, hydrophobic components in the extracellular polymeric substance promoted aggregation between bacteria. Bacteria, in turn, cooperated with each other through flexible metabolic patterns. Quorum sensing played an important role. Potentially degrading microorganisms such as Acinetobacter, Bacillus, Pseudomonas and Novosphingobium helped to mitigate the side effects of di-2-ethylhexyl phthalate. In addition, enhanced microbial interactions increased the consortia fitness and maintained the system stability. Combined with metagenomic and metatranscriptomic analysis, it was found that this microbial adaptation was enhanced by molecular regulation, including energy redistribution in amino acid synthesis and alterations in key metabolic pathways. Moreover, quorum sensing regulated the expression of many traits and genes, including horizontal transfer of ARGs. These findings highlight potential mechanisms of microbial adaptation to non-antibiotic pollutants stress, fill gaps in horizontal gene transfer pathways during anammox process and further facilitate the ARGs control through molecular and synthetic biology techniques.

抗生素的广泛使用导致环境中残留大量抗生素，进一步加速了抗生素抗性基因（antibiotic resistance genes, ARGs）的传播。除抗生素外，诸多非抗生素污染物——如纳米材料、消毒剂、非抗生素类药物及微塑料——也被报道可推动抗生素抗性基因的传播。邻苯二甲酸酯（Phthalates）是一类常见的塑料添加剂，可持续释放并在环境中累积，增塑剂-微生物相互作用已引发日益增多的环境与生态领域关注。已有研究表明厌氧氨氧化菌群（anammox consortia）可适应非抗生素污染物胁迫，但相关潜在的群落适应策略尚未得到充分阐释。本研究发现，厌氧氨氧化菌群的适应主要依赖微生物协同作用与分子调控。起初，胞外聚合物（extracellular polymeric substance, EPS）中的疏水组分可促进细菌间的聚集；随后细菌通过灵活的代谢模式相互协作，其中群体感应（Quorum sensing）发挥了重要作用。不动杆菌属（Acinetobacter）、芽孢杆菌属（Bacillus）、假单胞菌属（Pseudomonas）及新鞘氨醇杆菌属（Novosphingobium）等潜在降解微生物，可帮助缓解邻苯二甲酸二（2-乙基己基）酯（di-2-ethylhexyl phthalate, DEHP）的副作用。此外，增强的微生物相互作用提升了菌群适应性，维持了系统稳定性。结合宏基因组学（metagenomic）与宏转录组学（metatranscriptomic）分析，本研究发现这种微生物适应过程可通过分子调控得到强化，包括氨基酸合成中的能量重分配以及关键代谢通路的改变。此外，群体感应可调控诸多性状与基因的表达，包括抗生素抗性基因的水平转移（horizontal gene transfer, HGT）。上述研究结果揭示了微生物适应非抗生素污染物胁迫的潜在机制，填补了厌氧氨氧化过程中水平基因转移通路的研究空白，并可通过分子生物学与合成生物学（synthetic biology）技术进一步助力抗生素抗性基因的防控。