宏基因组技术研究泥岩母质发育的三种不同pH紫色土硝化微生物群落演变规律

Metagenomics-centric assembly of nitrifying communities in three pH-distinct soils with the same origin of parent material

摘要:

[目的] 揭示典型农田旱地紫色土硝化微生物的群落组成及其对pH的响应规律。[方法] 针对同一母质发育但pH差异显著的3种紫色土，利用宏基因组技术深度测序研究土壤中硝化微生物丰度和群落，包括氨氧化古菌（ammonia-oxidizing archaea，AOA），氨氧化细菌（ammonia-oxidizing bacteria，AOB），亚硝酸盐氧化细菌（nitrite-oxidizing bacteria，NOB）和全程氨氧化细菌（complete ammonia oxidizer，Comammox）。[结果] 土壤中硝化微生物的丰度占总微生物的2.130%–6.082%。3种紫色土中AOA、AOB和NOB的相对丰度有显著差异：酸性紫色土中AOA的相对丰度显著大于碱性紫色土，而AOB则相反；NOB的相对丰度在中性紫色土中最高。所有土样中均发现了1种全程氨氧化细菌Candidatus Nitrospira inopinata （Ca.N. inopinata），其在中性紫色土中相对丰度最高，占总微生物的0.203%。3种不同pH紫色土中AOA均以Nitrososphaera为主，NOB均以Nitrospira为主；酸性紫色土中AOB以Nitroscoccus为主，而中性和石灰性紫色土中则以Nitrosospira为主。Pearson相关性分析发现，土壤pH和铵态氮是影响硝化微生物丰度最大的两个因子。[结论] Comammox存在于3种不同pH紫色土中，且偏好中性环境；AOA、AOB和NOB群落结构和相对丰度都存在显著差异，结合相关性分析发现土壤pH和铵态氮是导致差异最重要的两个因子。

Abstract:

[Objective] Aimed to reveal the community compositions of nitrifiers and its response to pH in typical agricultural upland purple soils. [Methods] Metagenomics was used to investigate the abundances and communities of soil nitrifiers, including ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB) and complete ammonia oxidizers (Comammox) in three purple soils that developed from the same parent material but varied in pH. [Results] The abundances of nitrifiers accounted for 2.130%-6.082% of the total microorganisms. The relative abundance of AOA in acid soil was significantly higher than that of alkaline soil, whereas AOB was the opposite; the relative abundance of NOB in neutral soil was the highest. A specie of Comammox named Candidatus Nitrospira inopinata (Ca. N. inopinata) was found in all soil samples, and its relative abundance was the highest in neutral soil, accounting for 0.203% of the total microorganisms. The community composition analyses of nitrifier showed that:the Nitrososphaera and Nitrospira were the dominant AOA and NOB in all soil samples; Nitroscoccus was predominant in AOB populations in acid soil, whereas in neutral and alkaline soils the dominant AOB was Nitrosospira. Pearson correlation analysis reveals that the abundances of these nitrifiers were driven by soil pH and NH₄⁺. [Conclusion] Comammox existed in all soil samples and had a preference for a neutral environment; the relative abundances and community compositions of AOA, AOB, and NOB all showed a significant difference, soil pH and NH₄⁺ were the two most influential factors.