摘要
      外源污染物对藻界抗生素抗性基因（ARGs）的扩散和丰度、细菌群落和藻类与细菌相互作用的综合影响仍知之甚少。我们使用高通量测序和实时定量PCR研究了在纳米颗粒（银纳米颗粒（AgNPs）和赤铁矿纳米颗粒（HemNPs））和抗生素（四环素和磺胺嘧啶）胁迫下，藻界自由生活（FL）和颗粒附着（PA）细菌中ARGs的群落结构和丰度。同时，通过转录组和代谢组探讨了藻类与细菌相互作用的内在联系。结果表明，在纳米颗粒和抗生素的联合胁迫下，PA和FL细菌中磺酰胺和四环素ARGs的相对丰度分别增加了103-129%和112-134%。在与环境相关的浓度下，抗生素对ARGs的影响比纳米颗粒更大。变形菌门、厚壁菌门和拟杆菌门是ARGs的主要潜在宿主，是优势门。生活方式，即PA和FL，显著决定了ARGs和细菌群落的丰度。此外，藻类可以为细菌提供营养（碳水化合物和氨基酸），还可以产生抗菌物质（脂肪酸）。这种藻-细菌的相互作用可能间接影响ARGs的分布和丰度。这些发现为ARGs在微藻-细菌共生系统中的分布和扩散提供了新的见解。
Abstract
The comprehensive effect of exogenous pollutants on the dispersal and abundance of antibiotic-resistance genes (ARGs) in the phycosphere, bacterial community and algae-bacteria interaction remains poorly understood. We investigated community structure and abundance of ARGs in free-living (FL) and particle-attached (PA) bacteria in the phycosphere under nanoparticles (silver nanoparticles (AgNPs) and hematite nanoparticles (HemNPs)) and antibiotics (tetracycline and sulfadiazine) stress using high-throughput sequencing and real-time quantitative PCR. Meanwhile, the intrinsic connection of algae-bacteria interaction was explored by transcriptome and metabolome. The results showed that the relative abundance of sulfonamide and tetracycline ARGs in PA and FL bacteria increased 103–129 % and 112–134 %, respectively, under combined stress of nanoparticles and antibiotics. Antibiotics have a greater effect on ARGs than nanoparticles at environmentally relevant concentrations. Proteobacteria, Firmicutes, and Bacteroidetes, as the primary potential hosts of ARGs, were the dominant phyla. Lifestyle, i.e., PA and FL, significantly determined the abundance of ARGs and bacterial communities. Moreover, algae can provide bacteria with nutrients (carbohydrates and amino acids), and can also produce antibacterial substances (fatty acids). This algal-bacterial interaction may indirectly affect the distribution and abundance of ARGs. These findings provide new insights into the distribution and dispersal of ARGs in microalgae-bacteria symbiotic systems.

https://www.sciencedirect.com/science/article/abs/pii/S0304389422019951