仙山湖国家湿地公园湿地与旱地土壤细菌群落结构特征比较

Comparison of bacterial community structure between wetland and dryland in Xianshan Lake National Wetland Park

摘要:

【背景】湿地土壤微生物群落结构会因环境的变化自我调整，因而不同湿地环境会形成不同土壤菌群结构和分布特征。【目的】研究旱地与湿地土壤不同利用方式对土壤细菌的影响，以仙山湖国家湿地公园湿地和旱地两种土地利用方式(0−20 cm)作为研究对象。【方法】利用高通量测序技术对土壤细菌群落的物种组成、α多样性和丰度等进行分析，并结合土壤理化因子分析影响菌群结构的环境因子。【结果】仙山湖湿地系统土壤中存在的细菌隶属于49个门147个纲。在仙山湖湿地土壤的优势菌门(OTU>1%)中，旱地的优势菌门为酸杆菌门(Acidobacteria)、变形菌门(Proteobacteria)、绿弯菌门(Chloroflexi)、泉古菌门(Crenarchaeota)、放线菌门(Actinobacteria)、蓝藻门(Cyanobacteria)、芽单胞菌门(Gemmatimonadetes)、浮霉菌门(Planctomycetes)和拟杆菌门(Bacteroidetes)；湿地的优势菌门为变形菌门(Proteobacteria)、蓝藻门(Cyanobacteria)、拟杆菌门(Bacteroidetes)、绿弯菌门(Chloroflexi)、酸杆菌门(Acidobacteria)、厚壁菌门(Firmicutes)和硝化螺旋菌门(Nitrospirae)。在优势菌属(OTU>0.3%)中，旱地的优势菌属为Candidatus Solibacter、柯里氏念珠菌属(Candidatus Koribacter)、红游动菌属(Rhodoplanes)、伯克霍尔德菌属(Burkholderia)和分枝杆菌属(Mycobacterium)，湿地的优势菌属为地杆菌属(Geobacter)、拟杆菌属(Bacteroides)、慢生型根瘤菌属(Bradyrhizobium)、Dok59、神奇甲基菌属(Candidatus Methylomirabilis)和黄杆菌属(Flavobacterium)。湿地土壤与旱地土壤优势OTU均与有机质含量呈正相关，与含水量、pH呈负相关。此外，线性判别分析(linear discriminant analysis effect size, LEfSe)显示了旱地与湿地的土壤生物标记物与土壤理化性质的关系。【结论】土地利用方式变化能显著改变仙山湖国家湿地公园湿地土壤的细菌菌群结构，可为湿地土壤的保护提供理论依据。

关键词:湿地;旱地;16S rRNA基因;高通量测序

Abstract:

[Background] The microbial community structure of wetland soil will adjust itself according to the environmental changes. Therefore, different wetland environments will shape soil microbial communities with different structures and distribution characteristics. [Objective] To investigate the impacts of land use changes on soil bacteria in in dryland and wetland, we collected soil samples of two land use patterns (0−20 cm) from the wetland and dryland of Xianshan Lake National Wetland Park for analysis. [Methods] High-throughput sequencing was employed to study the composition, α-diversity, and abundance of soil bacterial communities, and the soil physical and chemical factors affecting bacterial community structure were analyzed. [Results] The bacteria in the soil of Xianshan Lake Wetland Park belonged to 147 classes of 49 phyla. The dominant phyla (OTUs>1%) in the dryland soil were Acidobacteria, Proteobacteria, Chloroflexi, Crenarchaeota, Actinobacteria, Cyanobacteria, Gemmatimonadetes, Planctomycetes, and Bacteroidetes, and those in the wetland soil were Proteobacteria, Cyanobacteria, Bacteroidetes, Chloroflexi, Acidobacteria, Firmicutes, and Nitrospirae. The dominant genus (OTUs>0.3%) were Candidatus Solibacter, Candidatus Koribacter, Rhodoplanes, Burkholderia, and Mycobacterium in the dryland and Geobacter, Bacteroides, Bradyrhizobium, Dok59, Candidatus Methylomirabilis, and Flavobacterium in the wetland. The dominant OTUs of wetland soil and dryland soil were positively correlated with soil carbon content and negatively correlated with soil water content and pH. The LEfSe results revealed the relationship between soil biomarkers and soil physical and chemical properties in the dryland and wetland. [Conclusion] Land use changes could vitally alter the bacterial community structure in the wetland soil of Xianshan Lake Wetland Park, it can provide theoretical basis for wetland soil protection.

Key words:wetland;dryland;16S rRNA gene;high-throughput sequencing