The Soil Microbiomes of American Ginseng (Panax quinquefolius) Cultivated in North America Differ by Location But Not Always by Disease Status

Abstract

One of the greatest challenges faced by ginseng producers is control of fungal pathogens which adversely affects harvest yields and is a contributing factor to replant failure syndrome. The goal of this project was to survey the soil microbiome of healthy versus diseased American Ginseng grown in North America. Soil associated with healthy and diseased plants were collected from commercial farms in Garett County, Maryland and Marathon County, Wisconsin. Environmental DNA metabarcoding was used to compare the bacterial and fungal microbiomes of healthy versus diseased plants from both locations. The most common bacteria occurred within the phylum Proteobacteria, Firmicutes, and Bacteroidota and the most common fungi occurred within Ascomycota, Basidiomytoca, Mortierellomycota and Glomeromycota. Overall Alpha- and Beta- diversities were statistically significant between the two locations. Community analyses (beta-diversity) of the Maryland site revealed a significant difference in the bacterial composition of soils associated with healthy versus diseased plants but not fungi. Conversely, there was a significantly different assemblage of fungi in healthy versus diseased associated soils from the Wisconsin site, but not for bacteria. Our results when compared to previous metabarcoding studies suggest there is little congruence between the soil microbiomes associated with cultivated ginseng and that we are still in the early stages of ginseng soil rhizosphere exploration.