Community structure of ammonia-oxidizing prokaryotes at the dry-up lake in Huitengxile grassland

Abstract:

Abstract:［Objective］To investigate the structure of ammonia-oxidation microbial communities in the wetlands to dry-up process at 99 degraded lakes of the Huitengxile grassland in the Inner Mongolia Plateau.［Methods］The microbial quantity of ammonia-oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB) were examined by most probable numberpolymerase chain reaction (MPN-PCR)．The clone libraries of amoA were constructed and phylogenetics were analyzed．With analysis of the soil properties，we evaluated the effects of wetlands degradation on ammonia-oxidation microbes communities．［Results］In 75% of the samples，the quantity of AOB communities was higher than that of AOA; moreover，quantity of bacterial were up to 18. 1-fold more abundant than Archaea's． The AOB microbial quantity was strongly correlated with NH4 + -N content in the soil． Phylogenetic analyses of the amoA gene fragments showed that most AOB sequences from degraded wetlands were affiliated with Nitrosomonas-like species and a few close to Nitrosospira． All AOA sequences belonged to the kingdom Crenarchaeote．［Conclusion］ Experimental results showed that quantity of ammonia-oxidation microbes increased but community diversity declined during wetlands degradation，and oxidation conditions and ammonium concentration in the soil might play important roles in the community structure of both the AOA and AOB．