Welcome to Chinese Agricultural Science Bulletin,

Chinese Agricultural Science Bulletin ›› 2025, Vol. 41 ›› Issue (30): 79-89.doi: 10.11924/j.issn.1000-6850.casb2025-0263

Previous Articles     Next Articles

Effects of Saline and Alkaline Stress on Abundance and Diversity of Community of Ammonia Oxidizing Microorganisms in Gray Desert Soil

XIANG Guiqin(), YE Yang, ZHANG Nan, GUO Huijuan()   

  1. Department of Resources and Environmental Sciences, Shihezi University, Shihezi, Xinjiang 832000
  • Received:2025-03-26 Revised:2025-08-07 Online:2025-10-25 Published:2025-11-04

Abstract:

Saline-alkali soils are prevalent in the arid regions of Xinjiang, unique physical and chemical properties lead to low soil fertility and the base ions interfere with nitrogen transformation processes. Currently, the effects of the saline-alkali environment on key nitrifying microorganisms, such as ammonia-oxidizing bacteria, remain poorly understood, limiting research on nitrogen cycling in these soils and hindering efforts to improve saline-alkali land. This study aimed to evaluate the effects of two types of saline-alkali stress (NaCl and Na2CO3 + NaHCO3) on the abundance, diversity, and community structure of ammonia-oxidizing microorganisms in gray desert soil from arid areas. This experiment used three treatments, including chloride stress (CS), alkaline stress (AS) and a control group (CK) with no salt-alkali stress, respectively, to evaluate the effects of saline-alkaline stress on cotton growth, soil physicochemical and the abundance and community structure of soil AOA and AOB. The results showed that saline-alkaline stress significantly reduced plant height and dry matter weight of cotton as well as soil NO3-N content and potential nitrification rate (PNR). Soil moisture content, salinity, pH and NH4-N content increased significantly under stress conditions. Both salt and alkaline stress decreased the amoA gene copy numbers of AOA, AOB, and the AOA/AOB ratios, respectively, with AOB showing higher amoA gene copy numbers than that of AOA. PNR was positively correlated with AOA and AOB amoA gene copy numbers. Additionally, the operational taxonomic units (OTUs) of AOB were more abundant than those of AOA under saline alkaline stress with alkaline stress causing a significant decrease in OTUs of AOB. Salt stress significantly decreased the Simpson and Shannon diversity index of AOB, whereas alkaline stress significantly increased the Simpson index of AOB. Salt stress also decreased the Pielou_e index of both AOA and AOB, while, alkaline stress increased the Chao1 index of AOA and AOB. The dominant phylum of the AOA community was Thaumarchaeota, while, Proteobacteria was the dominant phylum in the AOB community. The dominant genera for AOA were Candidatus Nitrosocaldus and Nitrososphaera, and they were Nitrosospira and Nitrosomonas for AOB. Both salt and alkaline stress significantly increased the relative abundance of Candidatus Nitrosocosmicus, Nitrosomonas, while decreasing Nitrososphaera, Nitrosospira. Redundancy analysis showed that soil properties, including SWC and pH played an important role in shaping the AOA and denitrifier communities, while AOB community structure was only significantly correlated with pH. These findings suggest that AOA and AOB contribute to nitrification in alluvial gray desert soils, with pH being the dominant factor affecting the growth of ammonia-oxidizing microorganisms and community structure.

Key words: saline-alkaline stress, AOA, AOB, potential nitrification rate, high-throughput sequencing