Deciphering the microbiome dynamics in an effective banana Fusarium wilt biocontrol interaction system

This study explored the effects of bacterial and fungal biocontrol agents (consortia) on the microbiome of Fusarium wilt (Foc TR4)-infected Cavandish banana soils in terms of alteration of prevalence and abundance. The results showed a significant shift in microbial diversity, dominance, abundance, evenness, richness and composition core and indicator microbiome in response to soil applied consortia and untreated controls. A total of 2857 bacterial OTUs from 331 families across 40 phyla dominated with Bacillaceae (40.2%), Acidobacteriaceae (14.2%), Haloarculaceae (12.6%), and Paenibacillaceae (9.4%). There were 4,868 fungal OTUs from 520 families across 18 phyla dominant with Mortierellaceae (20.9%), Cortinariaceae (7.6%), Aspergillaceae (6.2%), Pandeidae (5.6%), and Pyronemataceae (5.0%). Alpha diversity analysis indicated that bacterial diversity varied across treatments where T2 has the highest OTUs, while fungal diversity remained relatively stable across the treatments. Beta diversity and PCoA analysis revealed the differences in community compositions across treatments in both bacterial and fungal microbiome. Bacterial communities in T3 and T5 were highly similar, whereas T4 had a notable difference in fungal communities. This study identified a total of 192 bacterial core OTUs dominated with Firmicutes, Proteobacteria, and Acidobacteriia. In the case of fungi, 59 core OTUs from Ascomycota, Basidiomycota, and Mucoromycota are the most abundant ones within the treatments. Venn diagram revealed unique, common and shared OTUs suggesting antagonistic interactions of the soil applied consortia. DESeq2 analysis revealed a significant shift of core microbiome, where positive fold changes in Betaproteobacteria for bacterial, and Fusarium sp. for fungi were noticeable. Heatmap analysis revealed the treatment-dependent differences in community composition where T2 has higher bacterial abundance and T4 has higher fungal abundance suggesting that the biocontrol treatments affect the soil microbiome differently depending on the combinations and the origins of the consortia. The indicator species analysis identified 37 bacterial and 34 fungal OTUs that were specific and indicative of particular treatments that suggest microbial consortia might be selectively enhancing the growth of functionally beneficial microbial populations of the soil that promote soil health and disease suppressiveness. This study recommends that the use of biocontrol agents in the form of consortia would not only expand the diversity of the soil microbiome but also improve the effectiveness and the sustainability of Fusarium wilt management.