Comparison of soil bacterial diversity and community structure in different regions of Qinghai Province

Abstract:

[Objective] To investigate the diversity and community structure of soil bacteria in the farmlands in Qinghai Province. [Methods] High-throughput sequencing was employed to analyze the bacterial community structure and diversity in the soil samples of farmlands growing wheat, oilseed rape, and highland barley in Dulan, Huzhu, Gonghe, and Datong counties. Furthermore, the relationship between bacterial community structure and soil physicochemical properties was analyzed. [Results] The pH, moisture, and organic matter of soil, as well as the Chao1 and Shannon indexes and linear discriminant analysis effect size (LEfSe) of soil bacteria, showed significant differences in some of these indexes (P<0.01) but no significant differences among the three crops (P>0.05). The results of principal component analysis (PCA) showed that the bacterial community structure was different among different regions but highly similar in the farmlands of the three crops. A total of 3 127 operational taxonomic units (OTUs) and 3 694 OTUs were common in the four regions and in the farmlands of the three crops, respectively. The OTUs of soil bacteria were identified as 423 species, 450 genera, 276 families, 192 orders, 93 classes of 36 phyla. The four regions or three crops had similar dominant phyla, genera, and species, while these taxa differed in relative abundance. Soil moisture, pH, and organic matter were significantly correlated with Chao1 and Shannon indexes. Soil pH and organic matter had significantly positive or negative correlations with unclassified species, unclassified RB41, and unclassified Sphingomonas. Chao1 and Shannon indexes had significantly negative correlations with unclassified Sphingomonas but positive correlations with unclassified RB41 and unclassified Vicinamibacteraceae. [Conclusion] Regional differences had significant effects on soil physicochemical properties, bacterial community structure and diversity, which were more obvious than those of crop differences.