Bacteria account for a large proportion of the soil microbial community composition and diversity, and are closely related to ecosystem function and services, including the biochemistry cycle, energy flow and degradation of pollutant substances. 

To identify the key roles and underlying mechanism for assembling soil microbial community structures at regional scales, supervised by Prof. CHENG Xiaoli, YANG Fan, a PhD candidate from Wuhan Botanical Garden, conducted an investigation on soil bacterial community compositions from 20 locations in a transect of grasslands of southern China.   

By using high-throughput sequencing, the composition of bacterial community was measured. The soil microbial community diversity was analyzed for plant, soil, geographic properties, and pure spatial distance based on a distance-based approach and with variation partitioning based on canonical redundancy analysis. 

The soil bacteria richness and alpha diversity index was marginally correlated with plant richness and Shannon index. Soil pH and plant richness, as well as soil nutrient availability could explain the most variation of both the taxonomic and phylogenetic structures of bacterial community. The bacterial community exhibited the highest richness where the soil pH was 6.8. The determinant processes governed the assembly of soil bacterial community. 

These findings suggest plant functional traits and abiotic soil properties (e.g., soil pH and inorganic nitrogen) collectively drive soil bacterial diversity patterns but are not limited by pure geographic distance in southern China grasslands . 

This research was financially supported by the Strategic Priority Research Program B of the Chinese Academy of Sciences and the National Natural Science Foundation of China. Results have been published in Applied Soil Ecology entitled “Soil bacterial community composition and diversity in relation to edaphic properties and plant traits in the Grasslands of Southern China”. 

Locations of the sampling sites in the grassland mountains and grass slopes of south China (Image by YANG Fan) 

Redundancy analysis of prokaryotic community dissimilarities based on taxonomic distances along pH gradients with environmental factors (Image by YANG Fan)