Objective Effects of adding culture substrate in soil on the yield of ginseng roots and fungal community in the Pseudostellaria heterophylla rhizosphere were studied.

Methods Root rot disease incidence (DI) and crop yield of P. heterophylla plants cultivated in different type of fields using substrate to modify the ground soil were monitored. Diversity and structure of the fungal community in the rhizosphere at different plant growth stages were analyzed by high-throughput sequencing. A correlation study was conducted between the collected data.

Results The DI was reduced by 4.84-7.69% and root yield increased by 39.00-109.31% on the ginseng plants grown in the fields by the substrate addition in soil over control. The greatest effects were observed in the soil on hilly lands. At the ginseng seedling and expanding stages, the rhizosphere fungal community under treatments was lowered in richness but not significantly changed in diversity. At the harvest stage, on the other hand, the treatments increased the richness and reduced the diversity. In all rhizosphere soils, Ascomycota and Basidiomycota were the dominant microbes with a relative abundance greater than 85%. At genus level, Coniochaeta, Candida, Gibellulopsis, and Penicillium were predominant in the treatment soils, while Saitozyma, Didymella, Fusarium, and Epicoccum were dominant at the control sites. At harvest, the relative abundance of Fusarium rose significantly in the control soils and positively correlated with DI. The root yield of P. heterophylla plants positively correlated with the abundance of Gibellulopsis but negatively with that of Fusarium.

Conclusion By partially replacing rhizosphere soils with culture substrate at different types of fields of continuous cropping P. heterophylla, improvements on DI, root yield as well as fungal community structure and diversity were realized.