长期有机/无机肥配施对褐土细菌群落及抗生素抗性基因赋存的影响

Effects of long-term combination of organic and inorganic fertilizer on bacterial community and antibiotic resistance genes in cinnamon soil

为探明长期有机/无机肥配施对土壤细菌及抗生素抗性基因多样性的影响,以山西寿阳褐土长期定位试验为依托,采集5个有机/无机肥配施处理(N_(0)P_(0)M_(0),N_(2)P_(1)M_(1),N 4 P_(2)M_(2),N_(3)P_(2)M_(3)和N_(0)P_(0)M_(6))0~20 cm土层土壤样品,采用宏基因组测序技术研究有机/无机肥配施条件下褐土中细菌群落和抗生素抗性基因的差异。结果表明:长期有机/无机肥配施显著改变了土壤细菌及抗生素抗性基因的多样性,细菌优势门为变形菌门、酸杆菌门、放线菌门、芽单胞菌门和绿弯菌门。不同处理土壤共同抗性基因亚型有256个,土壤特有抗生素抗性基因亚型随施肥量的增加均呈现先增加后降低的趋势,且在N_(3)P_(2)M_(3)处理中达到最高。土壤中丰度较高的抗生素抗性基因种类有大环内酯类、多药类、万古霉素类、四环素类、氯霉素类,其中含量最高的抗性基因亚型为MacB、BcrA、MexW、MexF和pbp_(1)a。皮尔森相关性分析表明:土壤理化性质直接或间接地影响着细菌群落及ARGs的组成和变异,冗余分析进一步表明,抗生素抗性基因的变化受细菌群落结构的影响。抗生素抗性基因已经成为威胁人类健康的潜在污染物,农业生产中施用畜禽粪污时应充分腐熟并与化肥配合施用,以保障生态环境安全。

To explore the effects of long-term organic and inorganic fertilizer combined application on soil bacterial and antibiotic resistance gene diversity,_(0)~20 cm layer soil of five organic and inorganic fertilizer combined application treatments(N_(0)P_(0)M_(0),N_(2)P_(1)M_(1),N_(4)P_(2)M_(2),N_(3)P_(2)M_(3)and N_(0)P_(0)M_(6))were collected based on the long-term location test of cinnamon soil in Shouyang,Shanxi Province.Metagenomic sequencing technology was applied to study the difference of bacterial community and antibiotic resistance genes in cinnamon soil under combined organic/inorganic fertilizer conditions.Results showed that the diversity of bacteria and antibiotic resistance genes in soil was significantly changed by long-term organic/inorganic fertilizer combination.The dominant bacteria phyla were Proteobacteria,Acidobacteria,Actinobacteria,Gemmatimonadetes and Chloroflexi.There were_(2)56 soil common resistance gene subtypes in different treatments.Soil specific antibiotic resistance gene subtypes increased at first and then decreased with the increase of fertilizer application amount,reaching the highest in N_(3)P_(2)M_(3)treatment.The antibiotic resistance genes with high abundance in soil were macrolides,multidrugs,vancomycin,tetracycline and chloramphenicol.Among them,the resistance gene subtypes with the highest content were MacB,BcrA,MexW,MexF and pbp1a.Pearson correlation analysis showed that soil physical and chemical properties directly or indirectly affected the composition and variation of bacterial community and ARGs.Redundancy analysis further showed that the changes of antibiotic resistance genes were affected by bacterial community structure.Antibiotic resistance genes have become potential pollutants threatening human health.Livestock and poultry manure should be fully decomposed and combined with chemical fertilizer in agricultural production to ensure ecological environment safety.