Role of Microbiome Diversity in Soil Suppressiveness Against Fusarium Wilt in Vegetable Production Systems of Kano State

Fusarium wilt, caused by Fusarium oxysporum f. sp. lycopersici and related formae speciales, is a devastating soil-borne disease complex affecting tomato, pepper, and melon production in North West Nigeria. Disease-suppressive soils, characterized by high microbial diversity and abundance of antagonistic organisms, offer a biologically based alternative to fungicide-dependent management. This study investigates the relationship between soil microbiome diversity and the natural suppressiveness of agricultural soils against Fusarium wilt in vegetable production fields in Kano State. Soil samples were collected from 30 fields classified as historically disease-suppressive or disease-conducive based on farmer records and field diagnosis. Soil microbiome characterization was conducted using 16S rRNA amplicon sequencing and ITS1 fungal metabarcoding. Bioassay experiments were performed to confirm suppressive potential. Results indicate that disease-suppressive soils exhibited significantly higher bacterial diversity (Shannon H: 4.8 vs 3.4) and greater relative abundances of Pseudomonas, Bacillus, and Trichoderma genera compared to conducive soils. Structural equation modeling confirms a strong negative relationship between soil microbiome diversity and Fusarium wilt incidence. The study recommends soil microbiome enrichment through organic matter addition as a practical disease management strategy for vegetable producers in Kano State. Keywords: soil microbiome, Fusarium wilt, disease suppressiveness, vegetable production, Kano State