title: Community structure analysis of soil ammonia oxidizers during vegetation restoration in southwest China.
abstract: Soil ammonia oxidizers play a critical role in nitrogen cycling and ecological restoration. The composition and structure of soil ammonia oxidizers and their impacting factors were studied in four typical ecosystem soils, tussock (T), shrub (S), secondary forest (SF), and primary forest (PF), during vegetation restoration in the Karst region of Southwest China. The composition and structure of the ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) communities were characterized by sequencing the amoA and arch-amoA genes, respectively. The diversity of soil ammonia oxidizers (except in S) and plant Shannon diversity index gradually increased with vegetation restoration, and the ammonia oxidizer communities differed significantly (p < 0.001). Amplicons of AOA from the Nitrososphaera cluster dominated all four ecosystem soils. AOB Nitrosospira cluster 3b only appeared in PF and SF soils, while Nitrosospira cluster 3a species were found in all soils. Changes in AOB paralleled the changes in soil ammonium content that occurred with vegetation restoration. Redundancy analysis showed that the distribution of dominant AOB species was linked to pH, soil urease activity, and soil C/N ratio, whereas the distribution of dominant AOA species was mainly influenced by litter nitrogen content and C/N ratio. These results suggested that the composition and structure of the AOB community were more sensitive to changes in vegetation and soil ammonium content, and may be an important indicator of nitrogen availability in Karst ecosystem soils.
authors.affiliation: Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, The Chinese Academy of Sciences, Changsha, P. R. China; Graduate School of the Chinese Academy of Sciences, Beijing, P. R. China; Huanjiang Observation and Research Station for Karst Eco-Systems, Huanjiang, P. R. China.
authors.forename: Yueming
authors.initials: Y
authors.lastname: Liang
authors.forename: Xunyang
authors.initials: X
authors.lastname: He
authors.forename: Shichu
authors.initials: S
authors.lastname: Liang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Xiangbi
authors.initials: X
authors.lastname: Chen
authors.forename: Shuzheng
authors.initials: S
authors.lastname: Feng
authors.forename: Yirong
authors.initials: Y
authors.lastname: Su
mesh_terms: D000641:Ammonia / Q000737:chemistry / Q000378:metabolism*; D001105:Archaea / Q000235:genetics / Q000378:metabolism; D001419:Bacteria / Q000235:genetics / Q000378:metabolism; D001673:Biodegradation, Environmental; D002681:China; D017753:Ecosystem; D059013:Microbial Consortia / Q000235:genetics*; D009584:Nitrogen / Q000378:metabolism; D009586:Nitrogen Fixation; D010084:Oxidation-Reduction; D010802:Phylogeny; D006109:Poaceae; D012987:Soil / Q000737:chemistry*; D014197:Trees
chemical_list: D012987:Soil; D000641:Ammonia; D009584:Nitrogen
keywords: Ammonia-oxidizing archaea; Ammonia-oxidizing bacteria; Ammonium; Diversity; Karst; Litter; Urease activity; Vegetation restoration