稀土元素(REE)由于其对植物生长的各种有益作用,在农业生态系统中被广泛利用。然而,稀土的生态毒理效应和环境风险评估不佳。这里,我们使用基于宏基因组的方法研究了硝酸镧和硝酸铈对土壤原核生物和病毒金属抗性基因(MRGs)和抗生素抗性基因(ARGs)的影响。我们发现,随着两种REE化合物的增加,原核生物的Bacteroidetes和Chroloflexi的相对丰度降低。此外,低水平的稀土硝酸盐(0.05和0.1mmolkg-1土壤)抑制了病毒家族Phycodanaviridae,Rubriridae,Schitoviridae,而高水平(0.16和0.32mmolkg-1土壤)的REE硝酸盐抑制了病毒家族的Herelliviridae,轮状病毒科,podovirridae。ARGs不受低REE硝酸盐水平的显著影响。然而,高水平的两种REE硝酸盐增加了对大多数药物类别具有抗性的显性原核生物基因的丰度,如氨基糖苷,埃福霉素,氟喹诺酮,大环内酯,利福霉素.原核生物中MRG的丰度与REE硝酸盐化合物类型和输入率的变化不一致。在某些治疗方法中,MRGs仅在病毒中部分检测到,而在病毒中未检测到ARGs。一起,我们证明,在农业中过度使用稀土硝酸盐会增加ARGs通过原核生物而不是病毒传播的风险,尽管病毒群落发生了实质性转移。
Rare earth elements (REE) are extensively exploited in the agricultural ecosystems due to their various beneficial roles on plant growth. However, the ecotoxicological effects and environmental risk of REE are poorly assessed. Here, we investigated the effects of lanthanum and cerium nitrate on soil prokaryote and viral metal resistance genes (MRGs) and antibiotics resistance genes (ARGs) using a metagenomic-based approach. We found that relative abundances of prokaryote phyla Bacteroidetes and Chloroflexi decreased with increasing of both REE compounds. In addition, low level REE nitrate (0.05 and 0.1 mmol kg-1 soil) inhibited the viral family Phycodanaviridae, Rudiviridae, Schitoviridae, whereas high level (0.16 and 0.32 mmol kg-1 soil) REE nitrate suppressed the viral family Herelleviridae, Iridoviridae, Podoviridae. ARGs were not significantly affected by low level of REE nitrate. However, high level of both REEs nitrate increased the abundances of dominant prokaryote genes resisting to most of the drug classes, such as aminoglycoside, elfamycin, fluoroquinolone, macrolide, rifamycin. Abundance of MRGs in prokaryote did not change consistently with REE nitrate compound type and input rate. MRGs were only partially detected in the virome in some of the treatments, while ARGs was not detected in virome. Together, we demonstrated that overuse of REE nitrate in agriculture would increase the risk of dissemination of ARGs through prokaryotes but not virus, although viral community was substantially shifted.