soil metagenome

The sampling site as an American ginseng research farm located in Liuba County, Hanzhong, Shaanxi province (33° 38' N, 106° 43' E), in the Zhakoushi region, which is one of the main areas of American ginseng production in China. In order to avoid the effects of different crops on soil microbial communities, a plot of land that has never been planted in any crop was prepared for a ginseng crop in accordance with the common cultivation methods and used as the blank control. Farmland that has been planted in American ginseng (AG) for 4 years and is 50 m from the control soil was selected for the experimental samples. Soil samples were collected from the four corners and the diagonal center of each plot (C and AG). The soil samples were collected on April 30, 2017. Control soil samples (C) were collected by digging 10-20 cm into the fallow plot for a total of 8-10 g of soil, and soil from the 5 sampling points were combined to become three parallel (C1, C2, C3). Rhizosphere soil samples from around healthy ginseng (H) were collected by digging up healthy ginseng roots and shaking off the soil into a plastic bag, and the soil from the 5 sampling points were combined to become three parallel (H1, H2, H3). Rhizosphere soil samples from root rot-diseased ginseng (R) were collected by digging up diseased ginseng roots at the 5 points in the field, shaking off the soil into a plastic bag, combining the 5 samples, then dividing this mix into three parallel (R1, R2, R3). The V3-V4 region of the 16S rRNA gene was amplified using the primer set 338F (5′- ACTCCTACGGGAGGCAGCA -3′) and 806R (5′- GGACTACHVGGGTWTCTAAT-3′) for bacterial community analysis. For fungal community analysis, the Internal Transcribed Spacer (ITS1) sequence, including the partial 18S rRNA gene, was amplified with primer set ITS 5F (5′-GGAAGTAAAAGTCGTAACAAGG-3′) and ITS 1R (5′-GCTGCGTTCTTCATCGATGC-3′).