| Plant growth-promoting fungi and rhizobacteria control Fusarium damping-off in Mason pine seedlings by impacting rhizosphere microbes and altering plant physiological pathwaysAims Damping-off disease, caused by Fusarium oxysporum, affects the growth of Pinus massoniana seedlings. Plant growth-promoting fungi and rhizobacteria (PGPF and PGPR) are widely used in agriculture to control plant soil-borne disease, however, the joint mechanism by which they inhibit damping-off disease in forestry requires further exploration. MethodsThe current study screened for the ability of antagonistic PGPF and PGPR strains to inhibit the pathogen, and used soil microbiome and plant transcriptome technologies to characterize the biocontrol mechanism. ResultsPGPF strain 3Y, identified as Trichoderma longibrachiatum, and PGPR strain K29, identified as Burkholderia stabilis, were screened and found to strongly inhibit the growth of F. oxysporum through direct contact with the hyphae. The combined use of T. longibrachiatum and B. stabilis effectively reduced disease incidence and severity, and promoted the growth of P. massoniana seedlings, and enhanced soluble sugar, proline, SOD and POD activities. Compound strains treatment impacted the structure of rhizosphere bacterial microbial community, causing significant differences in the relative abundances of some key phyla and genera, promoting the enrichment of some beneficial microorganisms. Transcriptome profiles showed that combination treatment with the biocontrol strains induced the expressions of 8541 differentially expressed genes (DEGs). These genes participated in key biological pathways associated with starch and sucrose metabolism, plant hormone signal transduction, photosynthesis, antioxidant enzymes, and proline synthesis. ConclusionThe combined use of PGPF and PGPR strains controlled F. oxysporum infection of P. massoniana seedlings by regulating physiological responses and soil microbial community.
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https://doi.org/10.1038/s41929-026-01552-5
