Changes in bulk soil affect the disease-suppressive rhizosphere microbiome against Fusarium wilt disease

Harnessing disease-suppressive microbiomes constitutes a promising strategy for optimizing plant growth. However, relatively little information is available about the relationship between bulk and rhizosphere soil microbiomes. Here, the assembly of banana bulk soil and rhizosphere microbiomes was investigated in a monoculture system consisting of bio-organic (BIO) and organic management practices. Applying BIO practice in newly reclaimed fields resulted in a high-efficiency biocontrol rate, thus providing a promising strategy for pre-control of Fusarium wilt disease. The soil microbiota was further characterized by MiSeq sequencing and quantitative PCR. The results indicate that disease suppression was mediated by the structure of a suppressive rhizosphere microbiome with respect to distinct community composition, diversity and abundance. Overall microbiome suppressiveness was primarily related to a particular set of enriched bacterial taxa affiliated with Pseudomonas, Terrimonas, Cupriavidus, Gp6, Ohtaekwangia and Duganella. Finally, structural equation modeling was used to show that the changes in bulk soil bacterial community determined its induced rhizosphere bacterial community, which serves as an important and direct factor in restraining the pathogen. Collectively, this study provides an integrative approach to disentangle the biological basis of disease-suppressive microbiomes in the context of agricultural practice and soil management.