两种气候条件下不同有机质含量农田黑土真菌群落结构特征

Characteristics of fungal community structure in arable mollisols with different organic matter content under two climatic conditions

摘要:

【背景】东北黑土土壤肥沃，有机质含量丰富，是我国重要的粮食生产基地，同时也是受气候变化影响的敏感区。土壤微生物对环境因子变化的响应敏感，并且与土壤肥力密切相关，因此，研究环境因子改变对土壤微生物的影响有助于维持农田黑土生产力。【目的】探究有机质含量与气候条件对农田黑土真菌群落结构、多样性的影响，为全球气候变化条件下黑土区农业可持续发展提供重要基础数据和理论依据。【方法】利用黑土空间移位试验，采用Illumina Miseq测序技术对农田黑土真菌种类进行预测，并对其进行多样性和群落结构分析。【结果】两种气候条件下不同有机质含量农田黑土真菌种类均较丰富，土壤有机质含量对真菌多样性指数的影响不大，气候条件和施肥对真菌多样性的影响较大。在已知的真菌群落中，5种不同有机质农田黑土的优势菌门均为子囊菌门(Ascomycota)、担子菌门(Basidiomycota)和接合菌门(Zygomycota)，占总序列的92.5%。在气候较冷条件下，OTU数量、Chao1指数、Shannon指数和Simpson指数均出现不同程度的降低；施肥也会降低各有机质含量农田黑土中真菌物种数量和多样性，但是降低幅度随有机质含量升高而逐渐减小。气候因子、有机质含量、全氮、施肥和pH是影响不同有机质含量农田黑土中真菌群落结构发生变化的主要因素。【结论】有机质含量、施肥和气候均一定程度上改变了农田黑土中真菌群落多样性和群落结构。气候条件和施肥对农田黑土真菌群落结构影响较大，而有机质含量对其影响较小，但前两者的影响会随土壤有机质含量的增加而呈减弱趋势。这些影响在子囊菌门群落结构中表现明显。

Abstract:

[Background] Mollisols in Northeast China are rich in organic matter and fertile soil, which become an important food production base in China and a sensitive area affected by climate change. Soil microorganism is sensitive to the changes of environmental factors and closely related to the soil fertility. Therefore, it is helpful to maintain the productivity of mollisols by studying the influence of environmental factors on soil microorganism. [Objective] Explore the effects of organic matter contents and climatic conditions on fungal community structure and diversity in arable mollisols, and provide important basic data and theoretical basis for agricultural sustainable development in mollisols regions under global climate change. [Methods] Long-term soil spatial transplant experiments were used in the present study and the species of fungi in mollisols, and the diversity and community structure of fungi were analyzed by Illumina Miseq sequencing. [Results] Under the two climatic conditions, there were abundant fungal species in arable mollisols with different organic matter contents. The content of soil organic matter had little effect on fungal diversity, while the climate conditions and fertilizer application largely affected the fungal diversity. The dominant fungi phyla in mollisols with five organic matter contents were Ascomycota, Basidiomycota, and Zygomycota, accounting for 92.5% of all the sequences. Under the colder climate, OTU numbers, Chao1, Shannon and Simpson indices all decreased in varying degrees; fertilization also reduced the number and diversity of fungi in arable mollisols, but the decreasing rate decreased as increase of organic matter contents. Climate conditions, organic matter contents, total nitrogen, fertilization and pH were the main factors that driving the changes of fungal community structure in arable mollisols with different organic matter contents. [Conclusion] Organic matter contents, fertilization and climate conditions changed the composition, diversity, and structure of the fungal community in arable mollisols. Climate conditions and fertilization had a greater impact on the fungal community structure of mollisols with different contents, while organic matter contents had a smaller effect on it. However, the effects of the first two factors would weaken with the increase of soil organic matter contents, which was obvious in Ascomycota.