Abstract:

【Objective】 In order to explicate the indicating function of ammonia-oxidizing bacteria (AOB) on changes of environmental quality and the response of AOB to different long-term fertilizations, AOB diversity and community structure in dry highland of loess plateau were studied. 【Method】 Constructed amoA gene clone libraries, and the influence of CK, M, NM, PM and NPM fertilizer treatments on soil AOB diversity and community structure were analyzed by restriction fragment length polymorphism (PCR-RFLP). 【Result】 There were 59, 56, 83, 71 and 42 restriction endonuclease types from different fertilization, respectively. α-measurement indices analysis illuminated that there was variety differentia among five fertilizer treatments. The diversity was the highest in NM treatment and the lowest in NPM treatment. The Sorenson index was 0.61 between M and NPM(M-NPM), which indicated the highest community similarity. The lowest community similarity was existed in NM-CK and PM-CK, which Sorenson indices were both 0.15. Sorenson indices of other treatments were from 0.23 to 0.38. Phylogenetic analysis of amoA gene amino acid sequences showed that Nitrosospira cluster 3 sequences was dominant in all treatments, just the proportion of clones in each treatment belonging to Nitrosospira cluster 3a or 3b was different, and some clones were affiliated with the Nitrosospira cluster 4. 【Conclusion】 The results indicated that long term fertilization resulted in change of AOB community. Different fertilizer environments could lead to the significant species variation of soil AOB.

Key words: long-term fertilization')">long-term fertilization, ammonia-oxidizing bacteria, diversity, community structure