菌渣有机肥对番茄生长及土壤抗生素抗性基因累积的影响

Effects of Bacterial Residue Organic Fertilizer on Tomato Growth and Soil Antibiotic Resistance Genes Accumulation

摘要:

菌渣是抗生素合成中间体（6-氨基青霉烷酸）发酵过程中产生的固体废弃物，可能具有增加抗生素抗性基因（ARGs）传播的风险。目前，堆肥化处理方法具有无害化和资源化等特点，已成为菌渣处理的主要手段。本研究旨在探究菌渣有机肥对番茄生长及土壤ARGs累积的影响，以评估菌渣有机肥的生态风险。以经济作物番茄为研究对象，通过田间试验，分析以菌渣为原料制备的有机肥施入土壤后，对番茄生理指标、土壤理化性质、细菌群落结构及ARGs的多样性和丰度变化的影响。结果表明，施用菌渣有机肥可提升田间番茄地上部干物质量，连续两季施用可增加番茄维生素C含量，增加土壤硝态氮含量。菌渣有机肥处理后根际土壤细菌群落多样性无显著变化，但与常规施肥相比，变形菌门丰度显著升高，绿湾菌门丰度显著降低。施用菌渣有机肥后番茄土壤中ARGs种类多样性无显著变化，但氨基糖苷类抗性基因aada1、磺胺类抗性基因sul(II)显著高于常规复合肥处理。藤黄单胞菌（Luteimonas）丰度与四环素类、氨基糖苷类和磺胺类抗性基因丰度均具有显著正相关性。施用菌渣有机肥番茄根际土壤中未富集β-内酰胺类ARGs，四环素类、氨基糖苷类和磺胺类等ARGs在根际微生物中积累的风险有待进一步评估。

Abstract:

【Objective】Bacterial residue is a solid waste produced during the fermentation process of antibiotic synthesis intermediate (6-aminopenicillanic acid). Improper treatment will endanger environmental safety and increase the risk of the spread of antibiotic resistance genes (ARGs). At present, composting is the main method for treating residues due to its harmless and resourceful characteristics. Thus this study was designed to investigate the effects of composted bacterial residue organic fertilizer on tomato growth and soil ARGs accumulation and to assess the ecological risks of residue organic fertilizer. 【Method】In a field experiment, the tomato plant was used as the research object and the effects of organic fertilizer fermented from bacterial residue of penicillin synthesis intermediates on tomato growth, soil physicochemical properties, bacterial community structure, and the diversity and abundance of antibiotic resistance genes were analyzed【Result】The results showed that the application of residue organic fertilizer can increase the aboveground dry biomass of tomatoes in the field, and continuous application for two seasons can increase the vitamin C content of tomato fruits and soil nitrate nitrogen content. After being treated with organic fertilizer, there was no significant change in the diversity of bacterial communities in the rhizosphere soil. However, compared with conventional fertilization, the abundance of Proteobacteria significantly increased, while the abundance of Chloroflexi significantly decreased. There was no significant change in the diversity of ARGs in tomato soil after the application of residue organic fertilizer, but the amino glycoside resistance gene aada1 and sulfonamide resistance gene sul (II) were significantly higher than those in conventional compound fertilizer treatment. Also Luteimonas sp. was positively correlated with tetracycline, aminoglycoside, and sulfonamide resistance genes. 【Conclusion】After applying microbial residue organic fertilizer in tomato rhizosphere soil, there was no enrichment of β-lactam ARGs. However the risk of accumulation of tetracycline, aminoglycoside, and sulfonamide ARGs in rhizosphere microorganisms needs further evaluation.