Response of the rhizosphere soil fungal community to root rot infection of Plukenetia volubilis L

Abstract Background Root rot disease caused by soilborne pathogens is a threat to agriculture, affecting plant survival and leading to yield losses. The soil in which plants grow is inhabited by beneficial microbiome playing essential roles in various aspects of host functionality and fitness. However, this microbiome composition may change based on plant health status. Methods In the current study, we tested the pathogenicity of pathogenic fungi isolated from root rot infected P. volubilis plant tissues by inoculating them into healthy P. volubilis seedlings. Metagenomic sequencing was used to assess fungal community shifts in the rhizosphere of P. volubilis after root rot infection. Results Four Fusarium isolates and two Rhizopus isolates were found to be root rot causative agents in P. volubilis as they induced typical root rot symptoms in healthy seedlings. The metagenomic sequencing data showed that root rot infection altered the rhizosphere fungal community. In root rot infected soil, the richness and diversity indices increased or decreased depending on pathogens. The four most abundant phyla across all samples were Ascomycota, Glomeromycota, Basidiomycota, and Mortierellomycota. In infected soil, the relative abundance of each phylum increased or decreased depending on pathogen and functional taxonomic classification. Conclusions Based on our results, we concluded that Fusarium spp. and Rhizopus spp. cause root rot infection of P. volubilis. In root rot infected P. volubilis, the response of the rhizosphere fungal community was pathogen dependent. These findings may serve as a key point for a future study on biocontrol of root rot in P. volubilis.