Wang Yu, Huang Pei, Ye Fei, Jiang Yi, Song Liyan, Op den Camp Huub J M, Zhu Guibing, Wu Shengjun
Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China.
Department of Microbiology, IWWR, Radboud University Nijmegen, Nijmegen, 6525AJ, the Netherlands.
Appl Microbiol Biotechnol. 2016 Feb;100(4):1977-1986. doi: 10.1007/s00253-015-7083-2. Epub 2015 Oct 29.
The nitrite-dependent anaerobic methane oxidation (n-damo) mediated by "Candidatus Methylomirabilis oxyfera" connects the biogeochemical carbon and nitrogen cycles in a novel way. Many environments have been reported to harbor such organism being slow-growing and oxygen-sensitive anaerobes. Here, we focused on the population of n-damo bacteria in a fluctuating habitat being the wetland in the water level fluctuation zone (WLFZ) of the Three Gorges Reservoir (TGR) in China. A molecular approach demonstrated positive amplifications when targeting the functional pmoA gene only in the lower sites which endured longer flooding time in an elevation gradient. Only 1 operational taxonomic unit (OTU) in the lower elevation zone targeting the 16S ribosomal RNA (rRNA) gene was clustering into the NC-10 group a, which is presumed to be the true n-damo group. Moreover, a relatively low level of diversity was observed in this study. The abundances were as low as 4.7 × 10(2) to 1.5 × 10(3) copies g(-1) dry soil (ds) in the initial stage, which were almost the lowest reported. However, an increase was observed (3.2 × 10(3) to 5.3 × 10(4) copies g(-1) ds) after nearly 6 months of flooding. Intriguingly, the abundance of n-damo bacteria correlated positively with the accumulated flooding time (AFT). The current study revealed that n-damo bacteria can be detected in a fluctuating environment and the sites with longer flooding time seem to be preferred habitats. The water flooding may be the principal factor in this ecosystem by creating anoxic condition. The wide range of such habitats suggests a high potential of n-damo bacteria to play a key role in natural CH4 consumption.
由“食烷菌属嗜氧菌（Candidatus Methylomirabilis oxyfera）”介导的亚硝酸盐依赖型厌氧甲烷氧化（n-damo）以一种全新的方式连接了生物地球化学碳循环和氮循环。据报道，许多环境中都存在这种生长缓慢且对氧气敏感的厌氧菌。在此，我们聚焦于中国三峡水库（TGR）水位波动带（WLFZ）湿地这一波动生境中的n-damo细菌种群。一种分子方法表明，在海拔梯度中，仅在经受更长淹没时间的较低位点靶向功能性pmoA基因时会出现阳性扩增。在较低海拔区域靶向16S核糖体RNA（rRNA）基因的仅1个可操作分类单元（OTU）聚类到NC-10组a中，该组被推测为真正的n-damo组。此外，本研究中观察到的多样性水平相对较低。初始阶段的丰度低至4.7×10²至1.5×10³拷贝 g⁻¹干土（ds），几乎是已报道的最低水平。然而，在近6个月的淹水后观察到丰度增加（3.2×10³至5.3×10⁴拷贝 g⁻¹ ds）。有趣的是，n-damo细菌的丰度与累积淹水时间（AFT）呈正相关。当前研究表明，在波动环境中可以检测到n-damo细菌，淹水时间较长的位点似乎是其偏好的栖息地。水淹可能是通过创造缺氧条件而成为该生态系统中的主要因素。这类栖息地的广泛存在表明n-damo细菌在自然CH₄消耗中具有发挥关键作用的巨大潜力。
