Shandong Provincial Key Laboratory of Water and Soil Conservation and Environmental Protection, College of Resources and Environment, Linyi University, Linyi, China.
Linyi Agriculture and Rural Affairs Bureau, Linyi, China.
Appl Environ Microbiol. 2021 May 26;87(12):e0009221. doi: 10.1128/AEM.00092-21.
Land use types with different disturbance gradients show many variations in soil properties, but the effects of different land use types on soil nitrifying communities and their ecological implications remain poorly understood. Using CO-DNA-based stable isotope probing (DNA-SIP), we examined the relative importance and active community composition of ammonia-oxidizing archaea (AOA) and bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in soils under three land use types, forest, cropland, and greenhouse vegetable soil, representing three interference gradients. Soil net nitrification rate was in the order forest soil > cropland soil > greenhouse vegetable soil. DNA-SIP showed that active AOA outcompeted AOB in the forest soil, whereas AOB outperformed AOA in the cropland and greenhouse vegetable soils. Cropland soil was richer in NOB than in AOA and AOB. Phylogenetic analysis revealed that ammonia oxidation in the forest soil was predominantly catalyzed by the AOA cluster within the group 1.1b lineage. The C-labeled AOB were overwhelmingly dominated by cluster 3 in the cropland soil. The active AOB lineage was observed in the greenhouse vegetable soil, and it played an important role in nitrification. Active NOB communities were closely affiliated with in the forest and cropland soils, and with and in the greenhouse vegetable soil. Canonical correlation analysis showed that soil pH and organic matter content significantly affected the active nitrifier community composition. These results suggest that land use types with different disturbance gradients alter the distribution of active nitrifier communities by affecting soil physicochemical properties. Nitrification plays an important role in the soil N cycle, and land use management has a profound effect on soil nitrifiers. It is unclear how different gradients of land use affect active ammonia-oxidizing archaea and bacteria and nitrite-oxidizing bacteria. Our research is significant because we determined the response of nitrifiers to human disturbance, which will greatly improve our understanding of the niche of nitrifiers and the differences in their physiology.
土地利用类型的干扰梯度存在很大差异，土壤性质也会发生很多变化，但不同土地利用类型对土壤硝化群落及其生态意义的影响仍知之甚少。本研究利用 CO-DNA 稳定同位素探针（DNA-SIP）技术，研究了森林、农田和温室菜地三种不同干扰梯度下土壤中氨氧化古菌（AOA）和细菌（AOB）及亚硝酸盐氧化菌（NOB）的相对重要性和活性群落组成。土壤净硝化速率表现为森林土壤＞农田土壤＞温室菜地土壤。DNA-SIP 结果表明，森林土壤中活性 AOA 对 AOB 具有竞争优势，而农田和温室菜地土壤中 AOB 则优于 AOA。农田土壤中 NOB 比 AOA 和 AOB 更丰富。系统发育分析表明，森林土壤中的氨氧化主要由 1.1b 分支中的 AOA 簇催化。农田土壤中的 C 标记 AOB 主要由 3 簇主导。温室菜地土壤中也存在活性 AOB 类群，其在硝化作用中起着重要作用。活性 NOB 群落与森林和农田土壤中的 密切相关，与温室菜地土壤中的 和 密切相关。典范对应分析表明，土壤 pH 和有机质含量显著影响活性硝化群落组成。这些结果表明，不同干扰梯度的土地利用类型通过影响土壤理化性质来改变活性硝化群落的分布。硝化作用在土壤氮循环中起着重要作用，土地利用管理对土壤硝化菌有深远影响。不同土地利用梯度如何影响活性氨氧化古菌和细菌以及亚硝酸盐氧化菌尚不清楚。我们的研究具有重要意义，因为我们确定了硝化菌对人为干扰的响应，这将极大地提高我们对硝化菌生态位和生理差异的理解。
