摘要
     废水中常见的抗生素耐药性基因（ARGs）可能导致健康危机。人工湿地（CWs）可去除废水中的ARGs和磺酰胺（SA），但很少报道植物在这一过程中的重要性。我们使用专门设计的CW根盒，比较了三种湿地植物（互叶莎草、水杨和莎草）、样品与根的距离和SA的存在对1类整合素（intI1）和SA抗性基因（sul）环境丰度的影响。定量聚合酶链反应显示，目标基因在种植的CWs中的相对丰度显著低于未种植的CWs（P<0.05）。根际或近/中度根际（离根最近）的基质显示目标基因的平均相对丰度最低，而大块基质（没有根）显示出这些基因的最高丰度，而与种植的物种无关。此外，经过8周的废水处理后，植物的影响更加明显。SA处理组和未处理组的趋势相同，尽管前者的靶基因相对丰度显著较高（P<0.05）。与大量基质相比，SA组根际和近/中度根际的intI1和sul基因之间的相关性较弱，这表明大量基质和未接种CW的水平基因转移风险可能更高。偏最小二乘路径模型显示，溶解有机碳和氧含量显著影响SA浓度、微生物群落和intI1基因，然后共同形成sul基因。最后，冗余分析表明，sul基因的丰度受到大量基质中富集的细菌和未接种的CWs的影响。这些发现为湿地植物控制ARGs风险的重要性提供了新的见解。
Abstract
Antibiotic resistance genes (ARGs) commonly detected in wastewater can potentially lead to a health crisis. Constructed wetlands (CWs) remove ARGs and sulfonamides (SAs) from wastewater, but the importance of plants in the process is seldom reported. We compared the effect of three wetland plant species (Cyperus alternifolius, Juncus effuses, and Cyperus papyrus), sample distance from the root, and SA presence on the environmental abundance of class 1 integron (intI1) and SA resistance genes (sul) using specially designed CW rhizoboxes. Quantitative polymerase chain reaction revealed that the relative abundance of the target genes in planted CWs, especially in C. alternifolius planted CWs, was significantly lower than that in unplanted CWs (P < 0.05). The substrate in the rhizosphere or near-/moderate-rhizosphere (closest to the root) showed the lowest average relative abundance of the target genes, while the bulk substrate (without the root) showed the highest abundance of these genes, irrespective of the planted species. Further, the influence of plants was more evident after 8 weeks of wastewater treatment. The trend was the same in SA-treated and untreated groups, although the relative abundance of the target genes was significantly higher in the former (P < 0.05). The weaker correlation between the intI1 and sul genes in the rhizosphere and near-/moderate-rhizosphere in comparison to the bulk substrate in the SA group suggested that the risk of horizontal gene transfer was probably higher in the bulk substrate and unplanted CW. A partial least-squares path model revealed that dissolved organic carbon and oxygen content significantly influenced SA concentration, microbial community, and intI1 genes, and then shaping the sul genes together. Finally, redundancy analysis suggested that abundance of sul genes was influenced by bacteria enriched in the bulk substrate and unplanted CWs. The findings provide new insights into the importance for controlling risk of ARGs by wetland plants.

https://www.sciencedirect.com/science/article/abs/pii/S0048969722010695