73%) are the second and third dominant bacteria groups. The genes derived from the Archaea and Eukaryota also were detected and accounted for 1.64% to 2.04% and 4.35% to 5.33% among all the detected genes in all samples, respectively. Although gene numbers belonging to different phylogenetic structure varied considerably in different samples, the proportions of genes number of different phylogenetic structure in all detected genes is similar. For example, the ratio of Ī±-Proteobacteria ranged from 23.18% to 24.99% and the ratio of buy PR-171 Actinobacteria ranged from 9.30% to 10.97% (Additional file 1: Table S1). Therefore, these results indicated the overall functional genes as well as the phylogenetic diversity of
these alpine meadow soil microbial communities appeared to be quite high. Analysis of detected functional genes Among the 6143 genes detected in at least one sample, 567 were involved in carbon degradation, 202 in carbon fixation, 36 in methane oxidation, 18 in methane production, 754 in nitrogen cycling, 153 in phosphorus utilization, 279 in sulphur cycling, 2540 in organic remediation, 1275 in metal resistance, 126 in energy process, 193 in other category. Detected functional genes among these
six alpine meadow soil samples were analyzed by hierarchical clustering (Additional file 1: Figure S1). A total of 39 different clusters of genes were observed. Genes in group AZD9668 in vivo 5, group 32 and group 35 are presented in all of the samples. The most obvious patterns were group 11 (1054 [17.16%]) and group 33 (373 [6.07%]); instead of, the genes in group 11 is only present at sample SJY-GH which is the lowest altitude sample and group 33 is only present at sample SJY-YS which is the highest altitude
sample. The genes in group 11 were from functional categories involved in carbon degradation, carbon fixation, denitrification, nitrification, nitrogen fixation, phosphorus utilization, sulfite reductase, etc. Most of the genes in group 33 are involved in the carbon degradation, denitrification, nitrogen fixation, organic remediation, etc. These results showed that different microbial ADP ribosylation factor community structures existed in these samples and environment factors may influence them. To better understand microbial diversity involved in soil carbon cycling and nitrogen cycling, selected gene groups were further analyzed. Functional genes involved in the carbon cycling Microbe-mediated carbon cycling is one of the most important and complex process in the biogeochemical cycling. A total of 5196 gene probes belonging to carbon cycling were detected in the Geochip 3.0 [14]. Among them, 823 gene probes were detected in all six soil samples (Table 3). Sample SJY-GH and SJY-CD have the most and least detected gene numbers, respectively. Carbon fixation and carbon degradation are the two most important gene categories in the carbon cycling in all samples (Table 3).