The role of the biogas slurry microbial communities in suppressing fusarium wilt of cucumber

The clarification of the suppressive effect of biogas slurries (BSs) on soil-borne plant pathogens is needed for their large-scale use as a biocontrol tool in potting soil in order to understand the mechanisms of suppression. In this study, pig manure biogas slurry (PS) and vinasse biogas slurry (VS) were used to conduct assays of pathogen mycelial growth suppression and pot experiment to evaluate their effects on the growth of Fusarium. oxysporum f. sp. cucumerinum (FOC) mycelia and cucumber fusarium wilt. The microbial communities of the PS and VS were deeply analyzed to explore the key taxa and potential mechanisms. Results showed that the PS and VS have similar suppression on FOC mycelia and on the control efficiency, while they were significantly weakened when the PS and VS were used after sterilization. The microbial parameters of the two BSs were obviously different, and functional microbial taxa for disease resistance were observed in the two BSs. Spearman correlation showed that genera of the Pseudomonas, Ochrobactrum, Papiliotrema, etc., were the suppression-related taxa in the PS, while Leucobacter, unclassified_Microbacteriaceae, etc. in the VS. Overall, various key taxa in the PS and VS produced similar suppression on cucumber fusarium wilt.