Department of Civil and Environmental Engineering, Faculty of Engineering, University of Miyazaki, Miyazaki, Japan.
PLoS One. 2020 Mar 12;15(3):e0230174. doi: 10.1371/journal.pone.0230174. eCollection 2020.
The environmental DNA (eDNA) method is being increasingly applied in various environments. Although eDNA undergoes rapid degradation in aqueous environments, it has been detected in streams up to 10 km downstream from its source. As environmental bacteria can uptake free DNA, transfer their genetic traits, and amplify, there is a potential risk that they, rather than a target aquatic species, could become a source of measured eDNA. This study examined whether bacteria with incorporated fish DNA could be such a source by investigating the detectability of fish DNA generated by bacteria inhabiting river water and riverbed sediment. We attempted to detect common carp (Cyprinus carpio) eDNA in stream water and sediment samples and the DNA of common carp produced by bacterial colonies (Escherichia coli, total coliform, and heterotrophic bacteria) cultured from the samples. The eDNA was detected in the environmental samples but the carp DNA from the targeted bacteria was rarely detected in both water and riverbed sediment samples. Our results suggest that the risk of bacterium-induced false positive detection for fish eDNA is negligible.
环境 DNA（eDNA）方法在各种环境中得到了越来越广泛的应用。尽管 eDNA 在水相环境中会迅速降解，但它已在距离源头 10 公里的溪流中被检测到。由于环境中的细菌可以摄取游离 DNA、转移其遗传特征并进行扩增，因此它们（而不是目标水生物种）有可能成为测量 eDNA 的来源。本研究通过调查栖息在河水和河床沉积物中的细菌产生的鱼类 DNA 的可检测性，来研究是否可以将带有鱼类 DNA 的细菌作为这样的来源。我们试图检测来自溪流水样和底泥样本中的鲤鱼 eDNA，以及从这些样本中培养的细菌（大肠杆菌、总大肠菌群和异养菌）产生的鲤鱼 DNA。在环境样本中检测到了 eDNA，但在水样和底泥样本中几乎未检测到来自目标细菌的鲤鱼 DNA。我们的结果表明，细菌引起的鱼类 eDNA 假阳性检测的风险可以忽略不计。
