Tetracycline resistance genes are more prevalent in wet soils than in dry soils
Tetracycline resistance genes are more prevalent in wet soils than in dry soils
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四环素抗性基因在潮湿土壤中比在干燥土壤中更普遍
DOI：
10.1016/j.ecoenv.2018.03.041
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发表时间：
2018-07-30
影响因子：
6.8
通讯作者：
Hu, Jian
中科院分区：
文献类型：
--
作者：
Kang, Yijun;Li, Qing;Hu, Jian
本研究旨在揭示土壤含水量对四环素抗性基因在土壤中传播的影响。在实验室条件下，对4个不同土壤含水量（干土16%，湿土25%）的样品进行了添加和不添加猪粪（PM）的改良。定量聚合酶链反应（q-PCR）结果表明，无论施肥与否，湿润土壤中TRG（tetB、tetC、tetM、tetO、tetT和tetZ）的相对丰度均显著高于干燥土壤。此外，PM的应用提高了TRG的相对丰度。TRG的绝对拷贝数并没有随着16 S雷纳基因的减少而减少，这意味着大多数TRG可能位于兼性厌氧细菌中。然而，可培养的四环素耐药菌（TRB）在潮湿的土壤中不符合q-PCR结果，进一步表明，好氧菌可能无法解释的相对丰度的TRG的增加。湿润土壤中好氧TRB多样性明显高于干燥土壤，尤其是在第14和28天。好氧TRB在含PM的湿土和干土中的群落结构格局与干土不同。总之，这项研究表明，在干湿土壤之间的细菌群落的变化，特别是反映在好氧TRB和/或兼性厌氧TRB的群落结构的多样性，可能是一个重要的原因，在TRG的丰度变化背后。
This study aimed to reveal the effects of water content on the spread of tetracycline resistance genes (TRGs) in the soil. Amendments of four samples with different soil water contents, namely 16% (dry soil) and 25% (wet soil), and with or without pig manures (PM) were conducted under laboratory conditions. Quantitative polymerase chain reaction (q-PCR) results showed that the relative abundance of TRGs (tetB, tetC, tetM, tetO, tetT, and tetZ) in the wet soils was significantly higher than that in the dry soils whether under fertilization or non fertilization conditions. Moreover, PM application enhanced the relative abundance of TRGs. The absolute copies of TRGs did not decline with the decrease in 16S rENA genes in wet soils, implying that most TRGs were probably located in facultative anaerobic bacteria. However, cultivable tetracycline-resistant bacteria (TRB) in the wet soils were not in line with the q-PCR results, further indicating that aerobes might not account for the increases in the relative abundance of TRGs. Diversities of aerobic TRB were significantly higher in the wet soils than in the dry soils, especially on days 14 and 28. The patterns of community structures of aerobic TRB in the wet soils or dry soils containing PM were different from those in the dry soils. Together, this study showed that the variations in bacterial communities between the wet and dry soils, especially reflected in the diversity of aerobic TRB and/or community structure of facultative anaerobic TRB, might be an important reason behind the changes in the abundance of TRGs.