胞外聚合物介导的Pantoea dispersa对高浓度铜和镉的耐受机制

宋雨欣; 袁梦; 陈国涛; 谢光虹; 朱崇岭; 崔堂兵; 任源

文章摘要

宋雨欣,袁梦,陈国涛,谢光虹,朱崇岭,崔堂兵,任源.胞外聚合物介导的Pantoea dispersa对高浓度铜和镉的耐受机制[J].农业环境科学学报,2025,44(6):1486-1496.

胞外聚合物介导的Pantoea dispersa对高浓度铜和镉的耐受机制

Mechanisms of extracellular polymeric substances-mediated copper and cadmium tolerance in Pantoea dispersa

投稿时间：2025-05-14

DOI：10.11654/jaes.2025-0438

中文关键词: Cu²⁺ Cd²⁺ 胞外聚合物 Pantoea dispersa MSC14 生理响应转录组学

英文关键词: Cu²⁺ Cd²⁺ extracellular polymeric substances Pantoea dispersa MSC14 physiological response transcriptomics

基金项目:国家重点研发计划项目（2020YFC1808803）

作者	单位	E-mail
宋雨欣	华南理工大学环境与能源学院, 广州 510006
袁梦	华南理工大学环境与能源学院, 广州 510006
陈国涛	华南理工大学环境与能源学院, 广州 510006
谢光虹	华南理工大学环境与能源学院, 广州 510006
朱崇岭	华南理工大学环境与能源学院, 广州 510006
崔堂兵	华南理工大学生物科学与工程学院, 广州 510006
任源	华南理工大学环境与能源学院, 广州 510006 产业集群污染控制与生态修复教育部重点实验室, 广州 510006 广东省普通高等教育机构环境保护与生态修复重点实验室, 广州 510006	ceyren@scut.edu.cn

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中文摘要:

为探究微生物应对重金属胁迫的生存策略，明确胞外聚合物（EPS）在微生物重金属耐受中的功能及不同重金属耐受机制的差异，本研究测定了Cu²⁺和Cd²⁺胁迫下Pantoea dispersa MSC14表面的EPS产量，通过比较EPS去除前后生理生化指标的变化揭示了EPS在重金属耐受中的关键作用，并通过转录组学分析了其对Cu²⁺和Cd²⁺耐受机制的差异。结果发现，菌株MSC14在高达300 mg·L^-1的Cu²⁺和Cd²⁺胁迫下仍可表现出一定的代谢活性。同时，EPS含量显著增加，其中多糖和蛋白质的含量在Cu²⁺胁迫下最高分别增加19.0倍和9.3倍，Cd²⁺胁迫下最高分别增加5.8倍和7.8倍。菌株MSC14胞外吸附Cu²⁺和Cd²⁺的量显著高于胞内的积累量，在去除EPS后，Cu²⁺和Cd²⁺的总积累量分别减少了49.8%~52.0%和40.0%~68.6%，同时氧化应激程度加重。KEGG分析表明菌株MSC14对Cu²⁺和Cd²⁺的耐受机制存在一定差异。Cu²⁺胁迫诱导了菌株的氮代谢，促使Cu²⁺在细胞内还原为Cu⁺。Cd²⁺胁迫促进了小分子物种的合成与转运，菌株通过胞内沉淀和外排来提高Cd²⁺耐受性。研究表明，EPS是菌株MSC14耐受Cu²⁺和Cd²⁺的重要屏障，同时，菌株针对Cu²⁺和Cd²⁺形成了不同的特异性耐受策略。

英文摘要:

To explore the survival strategies of microorganisms in response to heavy metal stress, clarify the functions of extracellular polymeric substances（EPS）in the heavy metal tolerance of microorganisms, and reveal the differences in tolerance mechanisms to different heavy metals, this study measured the EPS production of Pantoea dispersa MSC14 and revealed the role of EPS in the tolerance mechanisms by comparing the changes in physiological indicators before and after EPS removal. Furthermore, transcriptomics elucidated the different tolerance mechanisms between Cu²⁺ and Cd²⁺. The results showed that strain MSC14 still exhibited considerable metabolic activity under 300 mg · L^-1 Cu²⁺ and Cd²⁺. Meanwhile, the content of EPS increased significantly. Under Cu²⁺ stress, the contents of polysaccharides and proteins increased to 19.0-fold and 9.3-fold respectively at the highest, while under Cd²⁺ stress, they increased by 5.8-fold and 7.8-fold respectively at the highest. The extracellular adsorption by strain MSC14 was significantly higher than intracellular accumulation. After removing EPS, the total accumulation decreased by 49.8%-52.0% and 40.0%-68.6% respectively, while the degree of oxidative stress was aggravated. KEGG pathway analysis indicated that Cu²⁺ induced nitrogen metabolism, facilitating the reduction of Cu²⁺ to Cu⁺, while Cd²⁺ enhanced small molecule synthesis and transport. This suggested that Cd²⁺ improved tolerance through intracellular precipitation and efflux. In summary, EPS serves as an important barrier for strain MSC14 to tolerate Cu²⁺ and Cd²⁺. Meanwhile, the strain has developed distinct specific tolerance strategies for Cu²⁺ and Cd²⁺

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