Soil bacterial endemism and potential functional redundancy in natural broadleaf forest along a latitudinal gradient.

Yuguang Zhang,Xiao Liu,Jing Cong,Ye Deng,Hui Lu,Jizhong Zhou,Diqiang Li

doi:10.1038/srep28819

Abstract

Microorganisms play key roles in ecosystem processes and biogeochemical cycling, however, the relationship between soil microbial taxa diversity and their function in natural ecosystems is largely unknown. To determine how soil bacteria community and function are linked from the local to regional scale, we studied soil bacteria community composition, potential function and environmental conditions in natural and mature broadleaf forests along a latitudinal gradient in China, using the Illumina 16S rRNA sequencing and GeoChip technologies. The results showed strong biogeographic endemism pattern in soil bacteria were existed, and the spatial distance and climatic variables were the key controlling factors for this pattern. Therefore, dispersal limitation and environmental selection may represent two key processes in generating and maintaining the soil bacterial biogeographic pattern. By contrast, the soil bacterial potential function is highly convergent along the latitudinal gradient and there were highly differing bacterial community compositions, and the soil chemistry may include the main factors active in shaping the soil bacterial potential function. Therefore, the soil bacterial potential function may be affected by local gradients in resource availability, and predicting soil bacterial potential function requires knowledge of abiotic and biotic environmental factors.

Highlights

Because: 1) the assessment methods may not fully reveal the real microbial function, such as the enzyme activity or particular functional gene2,11; 2) only the overall correlation between microbial taxonomic composition and the functional attributes is included, while excluding distinct taxa with specific functional attributes11,12; 3) certain microbial ecological processes are only apparent or important at a particular scale[10,13,14], and a comprehensive understanding of community-environment-function interactions is required at multiple scales[2]
Phylogenetic analysis showed that at least 29 known bacterial phyla were presented in these forest sites and all of these 29 detected phyla were presented at all sample sites
The decay of community similarity with geographic distance relationship is fundamental to our understanding of the biogeographic patterns of global biodiversity and its z value is a measure of the rate of turnover of species across space

Summary

Introduction

Because: 1) the assessment methods may not fully reveal the real microbial function, such as the enzyme activity or particular functional gene2,11; 2) only the overall correlation between microbial taxonomic composition and the functional attributes is included, while excluding distinct taxa with specific functional attributes11,12; 3) certain microbial ecological processes are only apparent or important at a particular scale[10,13,14], and a comprehensive understanding of community-environment-function interactions is required at multiple scales[2]. Yergeau et al showed a significant correlation between cellulase enzyme activity and the number of cellulase gene variants detected using GeoChip[20]. All these results indicated that GeoChip can be used to analyse the structure, functional activity and dynamics of microbial communities, and to link microbial communities with ecosystem processes and functions[21]. Forests are one of the most important and complex biomes in the terrestrial ecosystem They contain most of all known plant and animal species, and provide a variety of key resources and ecosystem services to humans, including food, drinking water, timber and medicines. To determine how soil bacteria community structure and function in the natural forest ecosystem are linked from the local to regional scale, we studied soil bacterial species composition, potential function and environmental conditions in 240 soil samples taken from 24 national natural reserves along a latitudinal gradient in China (Fig. S1 and Table S1)

Methods

Results

Conclusion