Alleviation of Pepper Continuous Cropping Obstacles by Chaetomium globosum CEF-082 Through Rhizosphere Microbiome Manipulation

Aims The inhibitory effect and mechanism of the biological control fungus Chaetomium globosum CEF-082 on pepper Continuous Cropping Obstacles (CCOs) were investigated. Specifically, it evaluated the effect of Chaetomium globosum CEF-082 on the composition structure of the soil microbial community in the rhizosphere of chili peppers. Methods Rhizosphere soil samples were collected from farmlands with continuous cropping for 3 years (Y3) and 20 years (Y20). Chaetomium globosum CEF-082 spore solution was treated in a greenhouse, and antagonism experiments were conducted on solid medium of glucose potato. Results The results indicated that prolonged planting led to severe soil nutrient loss, a 94.2% decrease in total nitrogen content, and a significant increase in the abundance of the pathogenic bacterium Fusarium. In vitro experiments confirmed that CEF-082 has a strong antagonistic activity against the main pathogenic bacteria of Fusarium. Greenhouse pot experiments have shown that the application of CEF-082 can significantly reduce the mortality rate of seedlings and improve the growth parameters of plants. High-throughput sequencing results showed that CEF-082 reshaped the rhizospheric microbial community, reduced the relative abundance of Fusarium, and might promote the colonization of beneficial Trichoderma species. Conclusions We believe that C. globosum CEF-082 alleviates CCOs through multiple mechanisms such as direct antagonism, regulation of rhizosphere microbiota, and improvement of soil nutrient availability. This study provides a sustainable strategy based on the microbiota for the management of soil-borne diseases in solanaceous crops.