State Key Laboratory of Microbial metabolism, and School of Life Science & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, P.R. China.
FEMS Microbiol Ecol. 2019 Sep 1;95(9). doi: 10.1093/femsec/fiz117.
Ammonium-oxidizing archaea (AOA) and bacteria (AOB) play crucial roles in ammonium oxidation in freshwater lake sediment. However, previous reports on the predominance of AOA and AOB in the surface sediment of Lake Taihu have been based on DNA levels, detecting the total abundance of microbiota (including inactive cells), and have resulted in numerous contradictory conclusions. Existing RNA-level studies detecting active transcription are very limited. The current study, using RNA-based real-time quantification and clone library analysis, demonstrated that the amoA gene abundance of active AOB was higher than that of active AOA, despite conflicting results at the DNA level. Further exploration revealed a significant positive correlation between the potential nitrification rate (PNR) and the abundance of AOA and AOB at the RNA level, with irregular or contradictory correlation found at the DNA level. Ultimately, using quantitative analysis of RNA levels, we show AOB to be the active dominant contributor to ammonium oxidation. Our investigations also indicated that AOB were more diverse in high-ammonium lake regions, with Nitrosomonas being the active and dominating cluster, but that AOA had an advantage in the low-ammonium lake regions.
氨氧化古菌（AOA）和细菌（AOB）在淡水湖底泥中的氨氧化过程中起着至关重要的作用。然而，以前关于太湖表层沉积物中 AOA 和 AOB 优势的报道是基于 DNA 水平的，检测了微生物群落的总丰度（包括非活性细胞），导致了许多相互矛盾的结论。现有的 RNA 水平检测活性转录的研究非常有限。本研究采用基于 RNA 的实时定量和克隆文库分析，表明活性 AOB 的 amoA 基因丰度高于活性 AOA，尽管在 DNA 水平上存在相互矛盾的结果。进一步的探索表明，在 RNA 水平上，潜在硝化速率（PNR）与 AOA 和 AOB 的丰度之间存在显著的正相关关系，而在 DNA 水平上则存在不规则或相互矛盾的相关性。最终，通过对 RNA 水平的定量分析，我们表明 AOB 是氨氧化的主要活性贡献者。我们的调查还表明，AOB 在高氨湖泊区域更加多样化，其中亚硝化单胞菌是活性和占主导地位的集群，但 AOA 在低氨湖泊区域具有优势。
