Abstract
Background: Jinsha earthen site in Chengdu, China, plays an important role in understanding the ancient culture and history of Shu civilization. The site is undergoing soil degradation due to physical, chemical and biological factors, while very little is known about the influence of biological factors on earthen sites. To investigate the biological factor, we analyzed microbial communities and physicochemical properties from samples with no obvious, mild, moderate and severe degradation, referred to as S1, S2, S3 and S4 sample groups, respectively.Results: Amplicon sequencing targeting the 16S rRNA gene and ITS for bacteria and fungi, respectively, revealed high bacterial and relatively low fungal diversity; the bacterial OTUs were assigned into 36 phyla and 617 genera and the fungal OTUs into 5 phyla and 205 genera. The relative abundances of Bacteroidetes, Proteobacteria and Firmicutes were higher and that of Actinobacteria lower with higher degree of degradation. In the genus level, the relative abundances of Bacteroides and Ralstonia were higher and that of Rubrobacter lower with higher degree of degradation. The distribution of the fungal genera in the four sample groups seemed more random than that of bacteria; however, the relative abundance of the yeast genus Candida was highest in the severely degraded sample group. For both bacteria and fungi, the differences in community composition were associated with differences in EC, moisture, pH, and the concentrations of NH 4 + , K + , Mg 2+ , Ca 2+ and SO 4 2- .Conclusion: Taken together, the microbial communities in soil with different degree of degradation were distinctly different at Jinsha earthen site, and degradation was accompanied with bigger changes in the bacterial than in the fungal community.
Analysis of soil microbial communities based on amplicon sequencing of marker genes
