title: Shifts in Abundance and Diversity of Soil Ammonia-Oxidizing Bacteria and Archaea Associated with Land Restoration in a Semi-Arid Ecosystem.
abstract: The Grain to Green Project (GGP) is an unprecedented land restoration action in China. The project converted large areas (ca 10 million ha) of steep-sloped/degraded farmland and barren land into forest and grassland resulting in ecological benefits such as a reduction in severe soil erosion. It may also affect soil microorganisms involved in ammonia oxidization, which is a key step in the global nitrogen cycle. The methods for restoration that are typically adopted in semi-arid regions include abandoning farmland and growing drought tolerant grass (Lolium perenne L.) or shrubs (Caragana korshinskii Kom.). In the present study, the effects of these methods on the abundance and diversity of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) were evaluated via quantitative real-time PCR, terminal restriction fragment length polymorphism and clone library analysis of amoA genes. Comparisons were made between soil samples from three restored lands and the adjacent farmland in Inner Mongolia. Both the abundance and community composition of AOB were significantly different between the restored lands and the adjacent control. Significantly lower nitrification activity was observed for the restored land. Clone library analysis revealed that all AOB amoA gene sequences were affiliated with Nitrosospira. Abundance of the populations that were associated with Nitrosospira sp. Nv6 which had possibly adapted to high concentrations of inorganic nitrogen, decreased on the restored land. Only a slight difference in the AOB communities was observed between the restored land with and without the shrub (Caragana korshinskii Kom.). A minor effect of land restoration on AOA was observed. In summary, land restoration negatively affected the abundance of AOB and soil nitrification activities, suggesting the potential role of GGP in the leaching of nitrates, and in the emission of N2O in related terrestrial ecosystems.
authors.affiliation: College of Biological Sciences, China Agricultural University, Beijing, China.
authors.forename: Zhu
authors.initials: Z
authors.lastname: Chen
authors.affiliation: College of Resources and Environmental Science, China Agricultural University, Beijing, China; Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing, China.
authors.forename: Wenliang
authors.initials: W
authors.lastname: Wu
authors.affiliation: College of Biological Sciences, China Agricultural University, Beijing, China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Shao
authors.affiliation: College of Resources and Environmental Science, China Agricultural University, Beijing, China; Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing, China.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: College of Resources and Environmental Science, China Agricultural University, Beijing, China; Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing, China.
authors.forename: Yanbin
authors.initials: Y
authors.lastname: Guo
authors.affiliation: College of Resources and Environmental Science, China Agricultural University, Beijing, China; Beijing Key Laboratory of Biodiversity and Organic Farming, China Agricultural University, Beijing, China.
authors.forename: Guochun
authors.initials: G
authors.lastname: Ding
mesh_terms: D000383:Agriculture; D000641:Ammonia / Q000378:metabolism*; D001105:Archaea / Q000235:genetics*; D001419:Bacteria / Q000235:genetics*; D044822:Biodiversity; D032602:Caragana / Q000254:growth & development; D002681:China; D055864:Droughts; D017753:Ecosystem; D052918:Environmental Restoration and Remediation / Q000379:methods*; D008129:Lolium / Q000254:growth & development; D058465:Nitrification / Q000235:genetics; D009584:Nitrogen / Q000378:metabolism; D058458:Nitrogen Cycle / Q000235:genetics; D010084:Oxidation-Reduction; D012150:Polymorphism, Restriction Fragment Length / Q000235:genetics; D012987:Soil; D012988:Soil Microbiology
chemical_list: D012987:Soil; D000641:Ammonia; D009584:Nitrogen