Regulating Root Fungal Community Using Mortierella alpina for Fusarium oxysporum Resistance in Panax ginseng

Abstract

Plant-associated microbes play important roles in plant health and disease. <i>Mortierella</i> is often found in the plant rhizosphere, and its possible functions are not well known, especially in medical plants. <i>Mortierella alpina</i> isolated from ginseng soil was used to investigate its effects on plant disease. The promoting properties and interactions with rhizospheric microorganisms were investigated in a medium. Further, a pot experiment was conducted to explore its effects on ginseng root rot disease. Physicochemical properties, high-throughput sequencing, network co-occurrence, distance-based redundancy analysis (db-RDA), and correlation analysis were used to evaluate their effects on the root rot pathogen. The results showed that <i>Mortierella alpina</i> YW25 had a high indoleacetic acid production capacity, and the maximum yield was 141.37 mg/L at 4 days. The growth of <i>M. alpina</i> YW25 was inhibited by some probiotics (<i>Bacillus</i>, <i>Streptomyces</i>, <i>Brevibacterium</i>, <i>Trichoderma</i>, etc.) and potential pathogens (<i>Cladosporium</i>, <i>Aspergillus</i>, etc.), but it did not show sensitivity to the soil-borne pathogen <i>Fusarium oxysporum</i>. Pot experiments showed that <i>M. alpina</i> could significantly alleviate the diseases caused by <i>F. oxysporum</i>, and increased the available nitrogen and phosphorus content in rhizosphere soil. In addition, it enhanced the activities of soil sucrase and acid phosphatase. High-throughput results showed that the inoculation of <i>M. alpina</i> with <i>F. oxysporum</i> changed the microbial community structure of ginseng, stimulated the plant to recruit more plant growth-promoting bacteria, and constructed a more stable microbial network of ginseng root. In this study, we found and proved the potential of <i>M. alpina</i> as a biocontrol agent against <i>F. oxysporum</i>, providing a new idea for controlling soil-borne diseases of ginseng by regulating rhizosphere microorganisms.