猪粪堆肥过程中砷转化基因、微生物与耐药基因的互作效应

    Interaction of arsenic biotransformation genes, microorganisms and antibiotic resistance genes during pig manure composting

    • 摘要: 畜禽粪便堆肥中的砷(As)污染和抗生素耐药基因(ARGs)污染研究较多,但2种污染的交互作用研究较少。该研究设置了5种As添加猪粪堆肥实验:T1(对照组,0 mg/kg)、T2(砷酸钠10 mg/kg)、T3(砷酸钠20 mg/kg)、T4(沙洛克砷10 mg/kg)和T5(沙洛克砷20 mg/kg),采取智能芯片实时PCR、高通量荧光定量PCR和高通量测序等方法,研究堆肥过程中ARGs、As生物转化基因(ABGs)、微生物群落及其代谢功能的互作效应。结果显示:添加外源As一定程度上提高了堆体温度,提高了胡敏酸/富里酸的比值。有机As刺激了ABGs产生,而无机As引起了更多ARGs产生。As添加对微生物群落影响显著,无机As对微生物群落的作用更快(约20 d),而有机As需要经过一定的转化才能起作用(60 d);两种外源As均增加了厚壁菌门(Firmicutes)相对丰度,但对一些其他菌群的影响作用明显不同(unidentified_Bacteria);同时微生物的代谢基因也受到了不同程度的影响。通过RDA分析和网络共现关系可知,微生物中Firmicutes和Bacteroidota对ARGs变化的贡献率分别为15.6%和18.7%,环境因素中的含水率和有机质含量对ARGs变化的贡献率分别为18.7%和12.1%;此外,ABGs与ARGs具有一定的正相关性。该研究结果有助于明晰复合污染物之间的内在互作机制。

       

      Abstract: Arsenic (As) pollution and antibiotic resistance genes (ARGs) pollution in livestock manure compost have been studied much, but the interaction between the two has been studied very little. Therefore, five kinds of As addition experiments of pig manure composting were set up in this study: T1 (control group, 0 mg/kg), T2 (sodium arsenate 10 mg/kg), T3 (sodium arsenate 20 mg/kg), T4 (saroxyarsenic 10 mg/kg) and T5 (saroxyarsenic 20 mg/kg). The interaction of ARGs, As biotransformation genes (ABGs), microbial communities and their metabolic functions during composting were studied, using smart chip real-time PCR, high-throughput fluorescent quantitative PCR and high-throughput sequencing. The results showed that the addition of exogenous arsenic increased the temperature, inhibited the degradation of organic matter, and increased the ratio of humic acid to fulvic acid. Organic arsenic stimulated more ABGs production, while inorganic arsenic induced more ARGs production. The effect of arsenic addition on microbial community was significant. The effect of inorganic arsenic on microbial community was faster (about 20 days), while the effect of organic arsenic required a certain transformation (60 days). Both kinds of exogenous arsenic increased the relative abundance of Firmicutes, but had different effects on other bacteria groups. At the same time, the metabolic genes of microorganisms were also affected in different degrees by As addition. Through RDA analysis and network co-occurrence, it can be seen that the contribution rates of Firmicutes and Bacteroidota to the change of ARGs were 15.6% and 18.7% respectively, and the contribution rates of water content and organic matter content to the change of ARGs were 18.7% and 12.1% respectively. In addition, ABGs and ARGs have some positive correlations. The results of this study will help to clarify the internal interaction mechanism between complex pollutants.

       

    /

    返回文章
    返回