氮依赖型甲烷厌氧氧化菌的整合

Integrated analysis of nitrite-dependent anaerobic methane oxidation bacteria

摘要:

氮依赖型甲烷厌氧氧化菌（nitrite-dependent anaerobic methane oxidation bacteria，n-damo细菌，属于NC10门）是最近10年来微生物生态学领域的研究热点。然而，对该类群基于现有数据的生态分布、群落结构和系统进化的整合分析还未见报道。[目的]为了更好地将近年来针对该类群的研究做一次全面梳理，本文通过整合前人已有发表数据和结合自身实验数据两方面进行。[方法]一方面，利用NCBI数据库（数据搜集到2016年11月）中所有n-damo细菌序列对其进行生物信息学分析；另一方面，对大九湖泥炭地表层泥炭利用16S rRNA二代测序技术对该类群进行检测，并同前人数据进行对比。[结果]n-damo细菌主要在沉积物、湿地和水稻土检出；基于pmoA基因的n-damo细菌的平均检出率是基于16S rRNA基因检出率的7倍，但是这两类基因分子标记物所得到的多样性指数保持相对稳定（1.4-3.4）；贫氮的大九湖泥炭其NC10的丰度仅为0.067%。[结论]n-damo类群种群相对稳定，暗示其行使的生态功能相对单一；贫氮的大九湖泥炭其极低的NC10丰度暗示氮对NC10是限制因子；具有真正氮依赖型甲烷厌氧氧化细菌的Group A可能只占很少的一部分（小于20%），暗示出该类群真正的生态潜能需要进一步评估。本次整合分析为更好的理解n-damo细菌的生活环境、评估不同基因分子标记物下n-damo细菌的检出率、不同亚类群比如Group A和Group B等的丰度和真正的潜在生态功能提供参考。

Abstract:

[Objective] In order to give a full overview including ecological distribution, community structure and phylogenic diversity.[Methods] All n-damo bacteria related sequences from NCBI databases (data collected until November 2016) and together with our experimental data from Dajiuhu surface peat samples through 16S rRNA illuminia sequencing were set to do the bioinformatics analysis.[Results]n-damo bacteria were mainly detected in the sediment, wetlands and paddy soil. The average detection rate of n-damo bacteria based on pmoA gene was 7 times more than that based on 16S rRNA gene, whereas Shannon-Wiener index (1.4-3.4) remained relatively stable. The abundance of NC10 was only 0.067% from Dajiuhu peatland, which was the lowest abundance in all published data, indicating nitrogen was a limiting factor for NC10. Group A including Methylomirabilis oxyfera which had been test to have the anaerobic methane oxidation accounts for only a little bit (less than 20%), suggesting that the real ecological potential of methane consumption by n-damo bacteria need more deep study. [Conclusion] The integrated analysis on n-damo bacteria deepen our knowledge of this functional group and may give some guideline for further study.