含四环素沼肥对蔬菜品质及抗性基因的影响

为探讨含四环素沼肥的生态毒性,采用盆栽试验研究了含四环素沼肥对小白菜品质、土壤微生物群落代谢功能多样性及抗性基因的影响. 结果表明:与CK相比,添加高浓度(15 mg/kg)四环素沼肥处理下,小白菜鲜质量和w(维生素C)分别降低了5.7%和16.7%,w(硝酸盐)增加了34.3%. Biolog微平板分析显示,添加高浓度四环素的沼肥显著提高了土壤微生物群落碳源利用多样性和物种丰富度. 实时荧光定量PCR分析发现,在小白菜幼苗期,添加高浓度四环素的沼肥处理下,土壤中四环素类抗性基因相对丰度比CK高出0.69~4.03倍. 无论沼肥中是否添加四环素,施肥后小白菜内生菌中均存在抗性基因,并且小白菜内生菌抗性基因相对丰度均以CK最高,比其他处理高出0.55~325.72倍. 研究显示,添加四环素的沼肥改变了小白菜品质和产量以及土壤微生物群落碳源利用多样性和物种丰富度,增加了土壤中四环素类抗性基因丰度,降低了小白菜内生菌的抗性基因水平. 

Effects of Biogas Fertilizers Containing Tetracycline on Vegetable Quality and Resistance Genes

Abstract: To explore the ecotoxicity of biogas fertilizer containing tetracycline, a pot experiment was conducted to investigate the effects of biogas fertilizer containing different concentration levels of tetracycline on bak choy quality, functional diversity of soil microbial community and tetracycline resistance genes in bak choy. The biogas fertilizer containing high concentration of tetracycline (15 mg/kg) reduced the fresh weight and vitamin C content of bak choy by 5.7% and 16.7% respectively, whereas the nitrate content increased by 34.3%. Biolog analysis showed that the biogas fertilizer containing high concentration of tetracycline significantly improved the diversity and richness of soil microbe. Real-time quantitative PCR analysis indicated that the relative abundance of tetracycline resistance genes in soils of the treatment adding high concentration of tetracycline were 0.69-4.03 times higher than those in the control soil at the bak choy seedling stage. Tetracycline resistance genes in bak choy endophytes were observed among all treatments, and the relative abundance of tetracycline resistance genes of the control were 0.55-325.72 times higher than those of the other treatments. The study suggested that application of the biogas fertilizer containing tetracycline changed the yield and quality of bak choy and the diversity and richness of soil microbe, increasing the abundance of antibiotic resistance genes in soil, but reducing the abundance of resistance genes in bak choy endophytes.