Comparative Studies on Soil Actinobacterial Biodiversity After Re-vegetation in the Urban and Rural Hydro-fluctuation Zone of the Three Gorges Reservoir Region

Abstract

This study aimed to understand the soil actinobacterial community diversity in the urban and rural hydro-fluctuation zone of the Three Gorges Reservoir region. The hydro-fluctuation zone of Chongqing Great Theatre in Jiangbei District and the Ruxi river basin in Zhong County, Chongqing, was chosen as the study area. Soil samples were collected in June 2015, to measure actinobacterial biodiversity using the terminal-restriction fragment length polymorphism (T-RFLP) molecular method. Results showed that:1 The actinobacterial biodiversity was different in the urban and rural hydro-fluctuation zone after artificial vegetation restoration. The actinobacterial biodiversity of the urban hydro-fluctuation zone was significantly higher than that of the rural hydro-fluctuation zone (P<0.05), which was most obvious in the surface soil. 2 The actinobacterial biodiversity of woodland was higher than that of grassland, but there was no significant difference in the actinobacterial biodiversity among the three soil layers in both the urban and rural hydro-fluctuation zone. 3 The dominant species of actinomycetes was different in different samples. 4 Redundancy analysis and the Monte-Carlo test revealed that water content and available nitrogen (AN) played a critical role in influencing actinobacterial biodiversity in the urban hydro-fluctuation zone (P<0.05). In contrast, the water content, organic matter (OM), available nitrogen (AN) and available phosphorus (AP) played a critical role in influencing actinobacterial biodiversity in the rural hydro-fluctuation zone of the Three Gorges Reservoir region (P<0.05). Thus, we concluded that the actinobacterial biodiversity of the urban hydro-fluctuation zone was significantly higher than that of the rural hydro-fluctuation zone in the Three Gorges Reservoir region, and such a result was attributed to the increased human disturbance and soil nutrients.