Chin J Plant Ecol ›› 2023, Vol. 47 ›› Issue (5): 699-712.DOI: 10.17521/cjpe.2022.0220

• Research Articles • Previous Articles     Next Articles

Response of ammonia oxidizing bacteria to nitrogen fertilization and plant litter input on desert steppe

ZHANG Ya-Qi1,2, PANG Dan-Bo1,2, CHEN Lin1,2, CAO Meng-Hao1,2, HE Wen-Qiang1,2, LI Xue-Bin1,*()   

  1. 1. Key Laboratory of Restoration and Reconstruction of Degraded Ecosystems in Northwestern China of Ministry of Education, Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwestern China, Ningxia University, Yinchuan 750021, China
    2. School of Ecology and Environment, Ningxia University, Yinchuan 750021, China
  • Received:2022-05-26 Accepted:2022-09-28 Online:2023-05-20 Published:2022-09-28
  • Supported by:
    National Natural Science Foundation of China(31960359);Ningxia Huizu Autonomous Region Key Research and Development Project(2021BEG02005);Third Batch of Ningxia Young Scientific and Technological Talent Support Project(TJGC2018068)


Aims This study aimed to explore the response of ammonia oxidizing bacteria (AOB) to litter decomposition and nitrogen application in the topsoil of desert steppe, and the main environmental factors influencing the AOB were also analyzed. Thus, this study will contribute to better understanding of the mechanism of nitrogen cycle function gene abundance in response to nitrogen deposition in arid and semi-arid desert steppe regions.
Methods We conducted the nitrogen fertilization experiment in the desert steppe in Yanchi, Ningxia. The four plant litters, including Sophora alopecuroides, Artemisia scoparia, Stipa breviflora and Agropyron mongolicum were selected as plant litter input treatments. The nitrogen fertilization treatments, including control (0 g·m-2·a-1) and nitrogen application (9.2 g·m-2·a-1), were applied to explore the response of AOB to nitrogen deposition and different litter inputs in top soil (0-5 cm) of desert steppe by fluorescent quantitative PCR and high-throughput sequencing.
Important findings Our results showed that there were 3 phyla, 4 classes, 6 orders, 7 families, 8 genera and 17 species of AOB in the topsoil of desert steppe under nitrogen application and litter decomposition. The AOB communities were mainly derived from Nitrosomonas and Nitrosospira, which were from beta-Proteobacteria, and Nitrosospira was the dominant species. Compared with the control, the gene copy number of AOB was significantly decreased under nitrogen application, indicating that nitrogen application inhibited nitrification in the topsoil of the desert steppe. Whereas, the response of AOB-ammonia monooxy genase subsuit A (amoA) gene abundance varied under different plant litter decomposition. Litter input could alleviate the inhibition of nitrogen enrichment on soil AOB-amoA gene abundance to a certain extent, but did not change the trend of soil AOB-amoA gene abundance. A redundancy analysis confirmed that soil organic carbon, total phosphorus, ammonium nitrogen and nitrate nitrogen contents were the key environmental factors affecting niche separation of AOB-amoA gene abundance in desert steppe soil. The results showed that nitrogen addition could significantly reduce the gene abundance of AOB-amoA, thereby affecting the nitrification and the direction of soil nitrogen transformation in the topsoil of desert steppe.

Key words: ammonia oxidizing bacteria, desert steppe, diversity, nitrogen deposition, litter addition, microbial ecology