Qiu YuHao¹, Liang WenJing¹, Li MeiQi¹, Zhu Hong¹, Peng Hao^1*, Si DouDou¹, Xie YuSi²

¹Shaanxi University of Technology, Hanzhong 723001, Shaanxi, China

²Shaanxi Agricultural Radio and Television School, Hanzhong 724400, Shaanxi, China

 

*Corresponding author’s email: huaohao808@126.com

Received: 09 September 2025 / Revised: 14 January 2026 / Accepted: 24 January 2026 / Published Online: 16 February 2026

 

Abstract

 

To address the severe threat of root rot caused by F. solani and F. oxysporum to American ginseng production and the limitations of chemical control, this study aimed to screen antagonistic actinomycetes and identify their key active substances. Actinomycetes were isolated from the rhizosphere soil of healthy American ginseng using the dilution plate method, and antagonistic strains were screened via the mycelial growth rate assay. Strain XF-3, with the highest inhibitory activity, was identified as S. murinus based on morphological, physiological-biochemical, and 16S rDNA sequence analyses. Its fermentation broth exhibited in vitro control efficacies of 56.09% and 66.27% against F. solani and F. oxysporum, respectively, in detached root inoculation tests. The key active metabolite was isolated via column chromatography and identified as actinomycin D using NMR and LC-MS. Mycelial growth inhibition assays showed EC₅₀ values of actinomycin D against F. solani and F. oxysporum were 2.08 μg/mL and 11.48 μg/mL, respectively. This study provides a candidate biocontrol strain S. murinus XF-3 and theoretical basis for the green management of American ginseng root rot, while expanding the application scope of actinomycin D in agricultural biocontrol.

 

Keywords: American ginseng root rot, Fusarium oxysporum, Fusarium solani, Metabolites, Actinomycin D

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