A More Comprehensive Community of Ammonia-Oxidizing Archaea (AOA) Revealed by Genomic DNA and RNA Analyses of amoA Gene in Subtropical Acidic Forest Soils

2018-11-23 本站

题目：A More Comprehensive Community of Ammonia-Oxidizing Archaea (AOA) Revealed by Genomic DNA and RNA Analyses of amoA Gene in Subtropical Acidic Forest Soils

期刊：Microb Ecol

作者：Ruo-Nan Wu1，Han Meng1， Yong-Feng Wang2,3 ，Wensheng Lan4，Ji-Dong Gu1

单位：1.Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, Faculty of ScienceThe University of Hong KongHong KongPeople’s Republic of China ;2.Guangdong Provincial Key Laboratory of Silviculture, Protection and UtilizationGuangdong Academy of ForestryGuangzhouPeople’s Republic of China;3.Laboratory of Microbial Ecology and ToxicologyGuangdong Academy of ForestryGuangzhouPeople’s Republic of China ; 4.Shenzhen R&D Key Laboratory of Alien Pest Detection TechnologyShenzhen Entry-Exit Inspection and Quarantine BureauShenzhenPeople’s Republic of China

摘要：Ammonia-oxidizing bacteria (AOB) and archaea (AOA) are the main nitrifiers which are well studied in natural environments, and AOA frequently outnumber AOB by orders especially in acidic conditions, making AOA the most promising ammonia oxidizers. The phylogeny of AOA revealed in related studies, however, often varied and hardly reach a consensus on functional phylotypes. The objective of this study was to compare ammonia-oxidizing communities by amoA gene and transcript based on both genomic DNA and RNA in extremely acidic forest soils (pH <4.5). Our results support the numerical and functional dominance of AOA over AOB in acidic soils as bacterial amoA gene and transcript were both under detection limits and archaeal amoA, in contrast, were abundant and responded to the fluctuations of environmental factors. Organic matter from tree residues was proposed as the main source of microbial available nitrogen, and the potential co-precipitation of dissolved organic matter (DOM) with soluble Al3+ species in acidic soil matrix may further restrict the amount of nitrogen sources required by AOB besides NH3/NH4 + equilibrium. Although AOA were better adapted to oligotrophic environments, they were susceptible to the toxicity of exchangeable Al3+. Phylotypes affiliated to Nitrososphaera, Nitrososphaera sister group, and Nitrosotalea  were detected by amoA gene and transcript. Nitrosotalea devantaerra and Nitrososphaera  sister group were the major AOA. Compared to the genomic DNA data, higher relative abundances of Nitrososphaera and Nitrososphaera sister group were recognized in amoA  transcript inferred AOA communities, where Nitrosotalea relative abundance was found lower, implying the functional activities of Nitrososphaera sister group and Nitrososphaera were easily underestimated and Nitrosotalea did not attribute proportionally to nitrification in extremely acidic soils. Further comparison of the different AOA community compositions and relative abundance of each phylotypes revealed by amoA genes and transcripts make it possible to identify the functional AOA species and assess their ecological role in extremely acidic soils.

关键词：Ammonia-oxidizing archaea (AOA)，Ammonia monooxygenase subunit A gene (amoA)，Organic matter，Aluminum，Nitrososphaera sister group，Nitrososphaera