Investigating soil microbiome changes during Panax quinquefolius cultivation in new gardens
Abstract
Ginseng (Panax quinquefolius) is susceptible to ginseng replant disease (GRD), resulting in root rot and decreased yield when ginseng is grown in soils previously used for ginseng crops. Although fungal and oomycete pathogens are implicated, GRD is a complex disease and the changes in the soil when initially cultivating ginseng that lead to GRD remain unclear. This thesis reported changes in the soil microbiome from three new gardens in Norfolk County, Ontario over three years starting from seeding with ginseng. Over this period of cultivation, metabarcoding of the V4 region of the 16S ribosomal RNA gene clearly showed a decrease in alpha diversity of the microbiome and a shift in microbial community composition. Families of microbes that are known to perform nitrogen fixation, ammonia oxidation, and toxin degradation increased in relative abundance. Future investigations should confirm whether any of the changes in microbial taxa during ginseng cultivation contribute to GRD.