Engineering Encapsidated TRV1 as a Complete VIGS Platform

Area of Science:

• Plant virology
• Molecular biology
• Agricultural biotechnology

Background:

• Tobacco Rattle Virus (TRV) is a bipartite RNA virus used for virus-induced gene silencing (VIGS).
• TRV1, encoding replicase and movement proteins, can move and replicate independently of TRV2, which encodes the capsid protein.

Purpose of the Study:

• To engineer TRV1 as a standalone, self-replicating RNA (srRNA) for targeted gene repression.
• To develop a sprayable, non-spreading VIGS system for agricultural applications.

Main Methods:

• TRV1 was engineered as an srRNA for systemic movement and gene silencing.
• TRV1 srRNAs were encapsidated using TRV2 capsid protein expressed from a separate vector.
• Encapsidated srRNAs were applied via spray to target plants.

Main Results:

• Achieved systemic movement of TRV1 srRNA and targeted gene repression up to 89%.
• Demonstrated successful spray-on application of encapsidated TRV1 srRNAs.
• Ensured no plant-to-plant spread as TRV2 components were not co-applied.

Conclusions:

• Developed the first sprayable TRV1-based srRNA for potent gene silencing.
• The system shows potential for agricultural gene repression due to TRV's broad host range and limited environmental persistence.
• Minimal phenotypic effects were observed, indicating a safe application method.