近日，華中農(nóng)業(yè)大學(xué)生命科學(xué)技術(shù)學(xué)院、農(nóng)業(yè)微生物資源發(fā)掘與利用全國重點(diǎn)實(shí)驗(yàn)室環(huán)境微生物課題組以“Toxic response of antimony in the Comamonas testosteroni and its application in soil antimony bioremediation”為題，在國際學(xué)術(shù)期刊Environment International上發(fā)表論文，闡明了微生物菌劑降低土壤銻毒性及銻生物有效性的機(jī)制，從而有效減少水稻銻積累。博士研究生羅雄為本文第一作者，李明順副教授為通訊作者，項(xiàng)目得到國家自然科學(xué)基金31970095的資助。
銻是一種劇毒的環(huán)境污染物，銻污染地區(qū)土壤銻含量遠(yuǎn)高于正常的背景濃度。銻能通過食物鏈進(jìn)入人體，導(dǎo)致癌變、心肌衰竭、肝壞死等疾病，嚴(yán)重威脅人類的健康。水稻可以過量富集銻，食用銻富集大米會(huì)嚴(yán)重威脅人類生命健康，尋找有效的銻修復(fù)方法成為亟待解決的問題，但水稻中銻氧化微生物驅(qū)動(dòng)的銻修復(fù)機(jī)制及技術(shù)缺乏研究。國內(nèi)外尚未報(bào)道微生物影響銻生物有效性和在水稻中驅(qū)動(dòng)銻修復(fù)的機(jī)制。
該研究評(píng)估了Comamonas testosteroni JL40在銻污染生物修復(fù)中的應(yīng)用潛力。發(fā)現(xiàn)菌株JL40通過細(xì)胞內(nèi)積累/結(jié)合、胞外固定、Sb（III）氧化、ROS清除、Sb（III）外排和生物被膜產(chǎn)生等途徑響應(yīng)銻的毒性?；诰闖L40對(duì)Sb（III）的固定和氧化功能，采用盆栽試驗(yàn)研究菌株JL40對(duì)銻的生物修復(fù)潛力。結(jié)果表明，在不同程度的銻污染土壤中，施加菌劑JL40后水稻糙米中銻積累量顯著降低，達(dá)到安全水平（<2.40 mg/kg）。此外， JL40菌株可以提高植物和土壤的健康，提高水稻產(chǎn)量。利用BCR和EDTA法對(duì)根際土壤中銻分級(jí)提取和單步提取，發(fā)現(xiàn)菌株JL40在土壤環(huán)境中可以起到鈍化和氧化銻的作用。在水稻盆栽過程中，菌株JL40接種30天后仍能保持在103 CFU/g以上。本研究為細(xì)菌在銻污染修復(fù)中的應(yīng)用奠定了重要基礎(chǔ)。
該工作是課題組2020年和2021年在Science of the Total Environment和Molecular Microbiology發(fā)表論文之后又一與土壤銻污染修復(fù)相關(guān)的研究成果。
英文摘要：
Antimony （Sb） is toxic to ecosystems and potentially to public health via its accumulation in the food chain. Bioavailability and toxicity of Sb have been reduced using various methods for the remediation of Sb-contaminated soil in most studies. However, Sb-contaminated soil remediation by microbial agents has been rarely evaluated. In this study, we evaluated the potential for the use of Comamonas testosteroni JL40 in the bioremediation of Sb-contamination. Strain JL40 immobilized more than 30% of the Sb（III） in solution and oxidized over 18% to Sb（V） for detoxification. Meanwhile, strain JL40 responds to Sb toxicity through such as Sb efflux, intracellular accumulation, biofilm production, and scavenging of reactive oxygen species （ROS）， etc. The results of the pot experiment showed the average Sb content of the brown rice was decreased by 59.1%, 38.8%, and 48.4%, for 1.8, 50, and 100 mg/kg Sb spiked soils, respectively. In addition, the results of plant, soil enzyme activity, and rice agronomic trait observations showed that the application of strain JL40 could maintain the health of plants and soil and improve rice production. The single-step and sequential extraction of Sb from rhizosphere soil showed that strain JL40 also plays a role in Sb immobilization and oxidation in the soil environment. During rice potted cultivation, bacterial community analysis and plate counting showed that the strain JL40 could still maintain 103 CFU/g after 30 days of inoculation. With phenotypic and differential proteomics analysis, strain JL40 conferred Sb（III） tolerance by a combination of immobilization, oxidation, efflux and scavenging of ROS, etc. Our study demonstrates the application of Sb-immobilizing and oxidizing bacteria to lower soil Sb and reduce accumulation of Sb in rice. Our results provide guidance for bacterial remediation of Sb-contaminated soil.
論文鏈接：https://doi.org/10.1016/j.envint.2023.108040
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