Rhizosphere microorganisms enhance the antiviral activity of the resistance inducer fTDP against tobacco mosaic virus

• The application of fTDP has altered the soil physicochemical properties and rhizosphere microbial community. • Rhizosphere microorganisms further enhance the antiviral effect of fTDP. • The combined application of fTDP and complex consortium exhibits a synergistic effect. Rhizosphere microorganisms can act synergistically with biocontrol agents to inhibit soil-borne plant diseases, however, their role in controlling leaf diseases remains unclear. They may, nonetheless, be key factors affecting the stability of biocontrol efficacy against leaf diseases. The resistance inducer fusion TEER-decreasing protein (fTDP) can activate salicylic acid-mediated systemic acquired resistance (SAR) to induce tobacco resistance to infection by the leaf pathogen tobacco mosaic virus (TMV). Here, using amplicon sequencing and quantitative reverse transcription PCR, we analyzed the effects of the rhizosphere microorganism on the antiviral function of fTDP. Simultaneously, a complex microbial consortium resistant to TMV was isolated and screened from the fTDP-treated group. The results showed that fTDP treatment alters soil physicochemical properties, restores the TMV-disrupted rhizosphere microbial community, and enriches beneficial bacterial genera. Furthermore, rhizosphere microorganisms enhanced the antiviral effect of fTDP. Eight bacterial strains isolated from soils after exogenous fTDP application induced plant resistant on TMV by improving the activity of tobacco defense enzymes and promoting plant growth. Six of these strains were successfully combined to construct a complex consortium, which together with fTDP amplified antiviral performance. In summary, fTDP induces changes in the structure of the rhizosphere microbial community, and these microorganisms participate in its antiviral activity. This study offers new insights into the mechanism by which biopesticides suppress foliar pathogens and also contributes to biosafety assessments.