A latitudinal gradient of microbial β-diversity in continental paddy soils

Aim The beta-diversity of plants and animals generally decreases with increasing latitudes. Here, we tested whether this relationship also holds for soil microbes at both functional and taxonomic levels. Location China. Time period Between June and October 2013. Major taxa studied Soil archaea, bacteria, and functional genes. Methods We used a spatially explicit 'L-shaped' sampling strategy in 39 paddy fields in China to study the pattern of soil microbial beta-diversity (i.e., species turnover, beta(z)) across a latitudinal gradient (19.75 degrees N to 47.58 degrees N), with 11 soil samples taken within a 100 m x 100 m plot from each field. Archaeal and bacterial communities were analysed by sequencing 16S ribosomal RNA gene amplicons using Illumina MiSeq; microbial functional genes involved in C/N/P/S cycling were detected by GeoChip. Results We showed that the microbial beta-diversity varied considerably across taxonomic and functional groups. For both soil microbial communities and functional genes, beta-diversity decreased significantly along elevated latitudes at the continental scale. Woesearchaeota of archaeal communities, Bacteroidetes of bacterial communities, and the functional genes involved in methane production displayed the greatest decreases. Both mean temperature during the growing season of rice plants and paddy soil heterogeneity contributed to the latitudinal patterns. Further analyses indicated that temperature was more important than soil heterogeneity in driving the beta-diversity of microbial communities and functional genes. Main conclusions These results highlight the importance of temperature-driven soil microbial beta-diversity and suggest the potential to predict the changes of microbial diversity with climate change.

Automated summary

The beta-diversity of soil microbes, both in terms of taxonomic groups and functional genes, decreases significantly with increasing latitudes at a continental scale. Archaeal community Woesearchaeota, bacterial community Bacteroidetes, and functional genes involved in methane production show the greatest decreases along elevated latitudes. Temperature during the growing season of rice plants and soil heterogeneity play important roles in driving the beta-diversity of microbial communities and functional genes.