Objective  Microbial communities in rhizosphere soils of healthy sweet potato plants and those infected by the stem rot disease (SPSR) were compared for ecological disease control.

  Method  Rhizosphere soil samples at fields of healthy and SPSR-infected sweet potatoes in between north and south planting regions and disease occurring western hilly areas of Huangyan, Taizhou City, Zhejiang Province, were collected. Enzyme activity and microbial community in the soil were analyzed using the traditional and high throughput sequencing techniques.

  Results  Compared with the rhizosphere soils of non-infected plants, those associated with the SPSR-infected sweet potatoes exhibited significant inhibition on the activities of urease, invertase, and alkaline phosphatase as well as significant increases on the microbial diversity and richness such as Chao1 and Shannon indices. At phylum level, the average relative abundance of dominant microbes, such as Actinobacteria, Verrucomicroba, and Bacteroidetes, were significantly lower in the SPSR soil, but that of Chloroflexi and Candidate-division-wps-2 significantly higher. At genus level, the average relative abundance of GP_1, Firmicutes-unclassified, and Gemmatimonas was higher in the SPSR samples, while that of Streptomycetaceae-unclassified, Streptacidiphilus, and Burkhoideria lower.

  Conclusion  In the rhizosphere soils of SPSR-infected sweet potato plants, the activities of some important soil enzymes were low. At both phylum and genus levels, the great variations in the abundance of dominant microorganisms existed between the healthy and SPSR rhizosphere soils.