湿度盐度pH协同驱动锡林河景观疣微菌群空间异质性

Moisture, salinity and pH co-driving spatial heterogeneity of Verrucomicrobial populations in Xilin River landscape

摘要:

[目的] 为了阐明锡林河不同景观要素间疣微菌群的空间分布异质性及环境驱动力。[方法] 本文基于生境及微地形差异选择水生的河床中心、河床边缘与牛轭湖床，湿生的低河漫滩与高河漫滩，旱生的低阶地与高阶地等景观要素，基于16S rRNA基因高通量测序技术研究不同景观要素土壤疣微菌群的景观异质性，结合土壤湿度等环境变量研究其驱动力。[结果] 景观要素内疣微菌群呈协同的分布特征，景观要素间呈趋异的分布特征。斯巴达杆菌纲的Chthoniobacter成员及疣微菌纲的突柄杆菌属等成员主要分布在水生河床中心，与砂粒含量存在显著正相关关系（P<0.05）；丰祐菌纲成员主要分布在湿生河漫滩，与pH存在正相关关系（P<0.05或P>0.05）；斯巴达杆菌纲的DA101_soil_group成员主要分布在旱生河流阶地，与盐度及养分含量等存在极显著正相关关系（P<0.01）。双组与三组环境变量的变异权重分析表明，湿度、盐度、pH对疣微菌群景观异质性的解释度分别高达24.7%与21.4%、24.3%与22.7%、23.1%与20.8%。[结论] 锡林河流域疣微菌群存在景观异质性。Chthoniobacter和突柄杆菌属等成员是河床中心景观要素的指示生物，DA101_soil_group是阶地景观要素的指示生物。湿度、盐度、pH协同驱动疣微菌群的景观异质性。

关键词:锡林河;景观要素;疣微菌;空间异质性;复合环境变量

Abstract:

[Objective] In this paper, our main goal was to clarify the spatial heterogeneity and environmental driver of Verrucomicrobial populations from different landscape components in Xilin River basin. [Methods] Based on the difference of habitat and microtopography, we selected the landscape components of aquatic riverbed center, riverbed edge and oxbow lakebed, hygric low floodplain and high floodplain, xeric low terrace and high terrace. Then we employed 16S rRNA gene high-throughput sequencing to study the landscape heterogeneity of soil Verrucomicrobial populations from different landscape components. We also explored environmental variables driving landscape heterogeneity of soil Verrucomicrobial populations combining with environmental variables (e.g. soil moisture). [Results] Spatial distribution of Verrucomicrobial populations showed convergent characteristics within landscape components and divergent characteristics between landscape components. The members of Chthoniobacter from Spartobacteria class and Prosthecobacter from Verrucomicrobiae class were mainly distributed in the aquatic riverbed center (RC), showing significant positive correlation with sand particle (P<0.05). Those of Opitutae class were mainly distributed in hygric floodplain, showing positive correlation with pH (P<0.05 or P>0.05). DA101_soil_group members of Spartobacteria class were mainly distributed in the xeric terrace, showing significant positive correlation with salinity and nutrients (P<0.01). Variation partitioning analyses of single, two groups and three groups of environmental variables showed that moisture, salinity and pH explained 24.7% & 21.4%, 24.3% & 22.7% and 23.1% & 20.8% of landscape heterogeneity of Verrucomicrobial populations, respectively. [Conclusion] Verrucomicrobial populations demonstrated landscape heterogeneity in Xilin River basin. Members of Chthoniobacter and Prosthecobacter were indicators of the riverbed center landscape component, DA101_soil_group was the indicator of the terrace landscape components. The combination of moisture, salinity with pH co-drove the landscape heterogeneity of Verrucomicrobial populations.

Key words:Xilin River;landscape components;Verrucomicrobia;spatial heterogeneity;combined environmental variables