Diversity of ammonia-oxidizing archaea in Tibetan Zoige plateau wetland

Abstract:

Abstract:［Objective］ Investigation of ammonia-oxidizing archaea (AOA) in nature environments is important to understand the global nitrogen cycling．However，little is known about the AOA community in plateau wetland．Therefore，we studied the composition and diversity of AOA in Zoige plateau wetland swamp soil．［Methods］ Total DNA was extracted from the swamp soil of three typical wetlands including A' xi pastoral area，Maixi pastoral area and Fenqu pastoral area locate in Zoige plateau wetland，and amoA gene was amplified with universally AOA amoA gene primers and then cloned．Then 80 positive clones for each clone library were chosen for further restriction fragment length polymorphism (RFLP) analysis，and the typical RFLP types were selected for sequencing and clustered into operational taxonomic units (OTUs) at 98% cutoff using the Mothur software． The MEGA 5.0 software was used for the amoA gene phylogeny analysis．［Results］ A total of 240 positive clones for all 3 libraries were used for RFLP analysis，and 15 specific amoA sequences were sequenced and clustered into 7 OTUs at 98% cutoff． Among them，OTU6 was detected in all of the 3 libraries and included 27% of the total specific clones． The phylogeny analysis showed that the 15 amoA sequences were grouped into 3 subgroups consisted of Zoige Wetland Clade 1 (4 OTUs)，Zoige Wetland Clade 2 (2 OTUs) and Zoige Wetland Clade 3 ( 1 OTU)．BLAST analysis showed that all OTUs were affiliated with the phylum Crenarchaeota． Correlation analysis showed that the Shannon diversity index (H') was significantly correlated with ammonia，nitrate/nitrite (P＜0.05)．［Conclusion］AOA in the Zoige plateau wetland swamp soil are all belonged to the Crenarchaeota，and their diversity is significantly correlated with soil ammonia，nitrate/nitrite content．