Physicochemical properties and fungal communities of forest soil combine to influence ginseng rusty root grade

Abstract

Ginseng rusty root (GRR) disease is a common ginseng disease that affects the quality and value of ginseng. Although some studies have focused on the mechanism of GRR incidence in farmland, little is known in forest conditions. The objective of this study was to clarify how GRR grades correlate with the physicochemical properties and fungi in forest soils. After examination of 38 sites in Changbai Mountain Range, 8 sites were selected for sampling, guided by their GRR gradings. The soil properties of forest soil samples were analyzed, and ITS-1 sequencing of the rhizosphere fungi was performed. The sequencing results were subjected to multivariate statistical analysis to explore GRR indicators. The results showed that soil pH, total nitrogen, total phosphorus, soil organic carbon, and moisture content varied significantly among 8 sampling sites. Total phosphorus and soil organic carbon were positively correlated with GRR grade. High GRR grade soils showed extremely high moisture content and low pH. At the phylum level, the abundances of Mortierellomycota, Rozellomycota, and Ascomycota were higher in high GRR grade soils. At the species level, Roesleria subterranea and Ilyonectria mors-panacis were abundant in high GRR grade soils. Overall, the grade of GRR is influenced by a combination of soil properties and the fungal community present in the soil. This study suggests that soil physicochemical properties and certain Ilyonectria spp. can be used as indicators for GRR grade. These scientific information will aid in selecting forest fields for ginseng planting.