Soil bacterial community diversity under different stages of degradation in zoige wetland

Abstract:

Both culture-dependent and culture-independent methods, denaturing gradient gel electrophoresis (DGGE) based on the sequence of 16S rDNA, were used to examine the microbial quantity, bacterial community structure and diversity in different soil types (Peat soil, Swamp soil, Meadow soil and Sandy soil) and soil detphs (0?20 cm, 20 cm?40 cm and 40 cm?60 cm) under different stages of degradation in Zoige Wetland. Experimental results showed that total microbial quantity decreased with the soil types (Peat soil>Meadow soil>Swamp soil>Sandy soil) and declined with soil depths (0?20 cm>20 cm? 40 cm>40 cm?60 cm). Bacterial community structure was affected by soil type more primarily than by soil depth. Bacterial community diversity generally declined with soil types (Peat soil>Sandy soil>Meadow soil>Swamp soil). However, no significant tendency was found for the soil depth. In addition, the total microbial quantity was strongly correlated with organic matter, total nitrogen and pH, and bacterial community diversity exhibited significant negative correlation with pH. Ten bands were excised from the DGGE gel and re-amplified for 16S rDNA sequencing. Based on the sequencing results, seven bands can be identified as related to γ-Proteobacteria, one close to α-Proteobacteria, and the other two belong to Bacteroidetes. These results provide evidence that Proteobacteria are the domain bacterial communities in the soil of Zoige Wetland.