ABSTRACT

Fungi play an important role in mediating soil functioning and plant nutrients absorption. Although nitrogen (N) addition and reduced precipitation can affect fungal community composition, the response of fungal taxonomic and functional groups to changes in soil N and water availability is still unclear. Here, we established a long-term field manipulations experiment of N addition and throughfall exclusion to investigate fungal communities’ response to N addition and reduced precipitation. Illumina Sequencing of ITS amplicons was used to examine soil fungal communities in winter and summer. Results showed that N addition, reduced precipitation and their combined effect significantly altered the soil fungal community composition. Basidiomycetes associated with humus decomposition dominated in ambient soil and Ascomycetes abundance dramatically increased and dominated in N addition in both winter and summer. Reduced precipitation and the combined effect significantly increased fungal richness and diversity. Moreover, the relative abundance of mycorrhizal and saprotroph fungal communities responded positively to reduced precipitation. Our results indicate reduced precipitation alleviated the competition between fungi, while N addition could reduce the rate decomposition of humus.

摘要

真菌在介导土壤功能和植物养分吸收方面起着重要作用。尽管氮（N）的添加和降水的减少会影响真菌的群落组成，但真菌的分类和功能基团对土壤氮和水的变化的响应仍然不清楚。在这里，我们建立了一个长期的氮肥添加和通流排除田间操作实验，以调查真菌群落对氮肥添加和降水减少的反应。ITS扩增子的Illumina测序用于检查冬季和夏季的土壤真菌群落。结果表明，氮的添加，降水的减少及其综合作用显着改变了土壤真菌的群落组成。与腐殖质分解有关的担子菌在周围土壤中占主导地位，而在冬季和夏季，子囊菌的丰度显着增加，而氮的添加则占主导地位。减少的降水及其综合作用大大增加了真菌的丰富性和多样性。此外，菌根和腐生真菌群落的相对丰富对降水减少有积极的反应。我们的结果表明减少的降水减轻了真菌之间的竞争，而氮的添加可以减少腐殖质的分解速率。