生物质炭阻控土壤中有机肥源抗生素抗性基因向植物迁移的规律与机制

Soil is one of the most important environmental carriers of antibiotic resistance genes (ARGs). Manure application used to fertilize crops select for and increase transmission of ARGs from farm-to-fork. Previous studies have found that biochar amendment can effectively impede the transport of soil ARGs to plant. However, the kinetics, pathways, and mechanism of reducing ARGs via biochar amendment is still unknown. In the proposed project, hundreds of ARGs will be quantified using highly parallel quantitative PCR and characterized with a novel target enrichment strategy followed by second generation sequencing. Experiments will be performed at multiple levels including simulation in the laboratory, well-defined tests in the glasshouse, and field scale studies in the environment. Project objectives include: i) investigating the impedance control law of biochar amendment on the migration of ARGs from soil to plants, ii) explore the accelerated dissipation dynamics of ARGs in the soil with biochar amendment, iii) illustrate the migration pathway of ARGs from soil with and without biochar amendment to plant, iv) reveal the synergistic effect of biochar and rhizosphere microorganisms on the dissipation of soil ARGs, v) determine the impedance efficiency of biochar amendment on the migration of soil ARGs to the plants, vi) elucidate the impedance mechanisms of biochar amendment on the ARGs migration in soil-plant system. The results can provide theoretical basis and technical support for the control of ARGs in the soil ecosysterm, and will be of great significance on the preservation of ecological environment and human health.

土壤是抗生素抗性基因最重要的环境载体，通过有机肥进入土壤环境中的抗生素抗性基因会向植物迁移，生物质炭能够有效阻控其迁移，生物质炭阻控的规律、途径与机制是什么？针对这些科学问题，本项目在前期工作基础上，以抗生素抗性基因新型污染物为研究对象，联合高通量荧光定量PCR与测序技术，分别从室内模拟、温室盆栽和田间实验尺度，研究生物质炭阻控土壤中抗生素抗性基因向植物迁移的规律，探讨生物质炭加速土壤中抗生素抗性基因消解的动力学特征，探究生物质炭阻控抗生素抗性基因从土壤向植物迁移的途径，揭示生物质炭-根际微生物协同消解抗生素抗性基因的机制，探明田间条件下生物质炭阻控抗生素抗性基因从土壤向植物迁移的效率，阐明生物质炭阻控抗生素抗性基因在土壤-植物系统中迁移的原理。为控制抗生素抗性基因在土壤生态系统中的迁移转化提供理论依据与技术支撑，对保护生态环境与人类健康具有重要意义。

土壤-植物系统是抗性基因从环境向人类传播扩散的重要途径之一，食物链更是大量抗性细菌和抗性基因进入人体最直接和最主要的途径。土壤中生物质炭的添加，能够有效阻控抗性基因的迁移，降低其对人类健康和生态安全的风险性。生物质炭阻控的规律、途径与机制是什么？针对这些科学问题，我们以抗生素抗性基因新型污染物为研究对象，结合高通量荧光定量PCR与微生物测序技术，开展了相关实验：在田间尺度下，探明了不同来源和堆肥方式对土壤中有机肥源抗生素抗性基因持久性的影响，对比了好氧、厌氧条件下菌群演替与抗生素抗性基因结构变化的互作效应，发现了厌氧土壤在抗生素抗性基因阻控方面上的积极作用；在温室条件下，探究了农田土壤有机肥源作用下不同作物（生菜、胡萝卜）中耐药基因消减迁移机制，明确了作物栽培模式、种植条件对抗生素抗性基因从土壤向植物传播途径的影响；通过室内培养，在有机肥源土壤中施加生物质炭，阐明了生物质炭阻控抗生素抗性基因在土壤-植物系统中迁移原理，探讨了生物质炭-植物联合修复抗生素抗性基因的消减机制；选用玉米秸秆生物质炭作为多孔载体，采用共沉淀法-离子交换法制备磁性生物质炭/季鏻盐复合材料，实现了耐药基因传播载体-活性菌体与游离DNA的杀灭去除，明确了磁性生物质炭/季鏻盐阻控抗生素抗性基因传播的机理，为控制抗生素抗性基因在土壤生态系统中的迁移转化提供理论依据与技术支撑，对保护生态环境与人类健康具有重要意义。