Enhancing plant resistance to tobacco mosaic virus through the combined application of Verticillium dahliae Aspf2-like protein and microelements.

BACKGROUND

Tobacco mosaic virus (TMV) poses a significant threat to global agriculture, infecting economically vital crops such as tobacco, tomato, pepper, and potato. Previous studies have suggested that the Verticillium dahliae Aspf2-like protein (VDAL) enhances plant resistance to TMV. This study investigated the preventive and therapeutic effects of VDAL, with and without microelements, on TMV resistance by analyzing plant hormone levels, defense related enzyme activities, and transcriptomic responses.

RESULTS

Plants were subjected to six experimental treatments: CK0 (untreated control, no TMV or VDAL treatment), CK (TMV inoculated control), T1 (preventive VDAL treatment), T2 (preventive VDAL + microelements), CT1 (therapeutic VDAL treatment), and CT2 (therapeutic VDAL + microelements). TMV inoculation (CK) significantly increased (P < 0.05) TMV content, jasmonic acid (JA), salicylic acid (SA) levels, and activities of defense related enzymes, including benzoic acid 2-hydroxylase (BA2H), peroxidase (POD), polyphenol oxidase (PPO), and superoxide dismutase (SOD), compared to CK0. Both preventive treatments (T1 and T2) effectively reduced TMV content and enhanced JA, SA, and defense related enzyme activities. Notably, the microelement-supplemented preventive treatment (T2) showed 37.73% greater reduction in TMV content compared to T1. Similarly, the therapeutic applications, CT2 reduced the TMV content by 32.50% than CT1. Treatments T2 and CT2 also increased the contents of JA by 5.48% and 2.88%, respectively compared to their respective controls. Transcriptomic analysis revealed that these treatments activated plant-pathogen interaction pathways and pathogen-associated molecular pattern-triggered immunity (PTI), with significant upregulation of key defense related genes (e.g., CALM, BAK1, PTI6, and WRKY33), indicating a robust antiviral defense response.

CONCLUSION

Overall, we conclude that the synergistic application of VDAL and microelements significantly enhances plant resistance to TMV through coordinated activation of phytohormone signaling, defense enzymes, and immune-related gene expression. This combined approach offers an effective, eco-friendly alternative for sustainable management of viral diseases in agricultural crops. © 2025 Society of Chemical Industry.