Plant-expressed mycovirus protein for broad fungal disease resistance in crops
A novel plant biotechnology approach that expresses a mycovirus replication initiator protein (REP) in planta to confer resistance against major fungal pathogens including Sclerotinia sclerotiorum, Botrytis cinerea, and Monilinia fruticola, offering a protein-based crop protection strategy for vegetables and dicot crops.
Overview
This technology leverages a discovery that the replication initiator protein (REP) from mycoviruses—specifically SsHADV-1 and SlaGemV-1—directly inhibits the growth of pathogenic fungi belonging to the family Sclerotiniaceae. Unlike viral coat proteins, which lack antifungal activity, REP proteins are toxic to fungal hosts on their own. By expressing REP heterologously in plants, the technology aims to provide intrinsic, protein-mediated resistance to devastating fungal pathogens such as Sclerotinia sclerotiorum (which infects virtually all dicot crops), Botrytis cinerea (a major pathogen of vegetable crops), and Monilinia fruticola (a stone fruit pathogen). This approach offers a potential alternative or complement to conventional fungicides, addressing significant agricultural losses while reducing chemical inputs.
Technical specifications
- Core mechanism: Heterologous expression of mycovirus-derived replication initiator protein (REP) in plant cells confers antifungal protection independent of viral coat protein.
- Target pathogens: Sclerotinia sclerotiorum, Botrytis cinerea, and Monilinia fruticola, all members of the Sclerotiniaceae family.
- Validated fungal targets: REP from SsHADV-1 and SlaGemV-1 demonstrated direct toxicity to fungal hosts without requiring coat protein co-expression.
- Model plant validation: Transient expression in Nicotiana benthamiana showed that fungal plug inoculations failed to establish infection on REP-expressing leaves, while controls (CP-expressing, buffer-infiltrated, empty vector, and null-infiltrated leaves) developed significantly larger lesions.
- Planned validation: Transient expression in N. benthamiana and N. tabacum, stable transgenic expression in Arabidopsis thaliana to the T1 generation, and bioassays comparing REP-expressing plants against multiple controls.
- Delivery format: Transgenic or transient expression constructs suitable for introduction into dicot crop species.
Technology readiness level
The technology is currently at an early-to-mid stage of development (TRL 3–4). A preliminary proof-of-concept has been completed through transient REP expression in Nicotiana benthamiana, demonstrating statistically significant protection against fungal infection. Future work will expand validation to additional model species, generate stably transformed Arabidopsis thaliana lines, and conduct broader bioassays within approximately one year. The goal is to demonstrate that heterologous REP expression inhibits fungal infection in a manner ready for further development toward crop adoption. Additional research is needed to evaluate efficacy in crop species, durability of resistance, and regulatory considerations for transgenic deployment.
About USDA
USDA is a U.S. federal executive department with an applied R&D enterprise delivered through a nationwide network of laboratories, field stations, and specialized repositories. Facilities include pilot‑scale processing lines and testbeds at co‑located university sites and research farms, enabling real‑world evaluation and scale‑up with USDA scientists. USDA engages industry through CRADAs, material transfers, cooperative field trials, and works with the Cooperative Extension System to speed adoption. Research is primarily supported by federal appropriations, with additional interagency collaborations and competitively funded programs. A dedicated tech transfer office manages IP and licensing and streamlines public‑private agreements.
delivered to your inbox.