Rhizospheric Fungal Communities and Their Role in Biocontrol of Fusarium in Robusta Coffee (Coffea canephora) in...

Rhizospheric microbial communities are critical to the health and productivity of coffee plantations. This study investigated the microbiome of robusta coffee (Coffea canephora) across three major cultivation areas in Vietnam (Dak-Nong, Dak-Lak, and Gia-Lai) to assess its role in Fusarium suppression. Using ITS ampliconbased metagenomics and culture-dependent approaches, we analyzed fungal community structure in relation to location, plant age, and health status. Metagenomic analysis revealed no significant differences in bacterial communities between healthy and diseased rhizospheres, whereas fungal communities showed clear distinctions, particularly in young plants (<2 years). These differences diminished in mature plants (≥2 years) but continued to vary with age (2-10 years). Healthy rhizospheres were enriched with beneficial fungi, while diseased soils contained more phytopathogenic genera. Fusarium was prevalent in all regions, with higher abundance in diseased soils, whereas Trichoderma, a known biocontrol agent, was more abundant in healthy soils but declined with plant age. Of 343 fungal isolates, 46 strains exhibited strong antagonistic activity against Fusarium, representing 10 genera, including Aspergillus, Penicillium, Gongronella, and Talaromyces. Although Trichoderma isolates were less frequent, they showed promising biocontrol potential. These findings underscore the role of rhizospheric fungi in managing Fusarium wilt and identify candidate biocontrol agents for sustainable robusta coffee cultivation.