Expanding Possibilities for Foreign Gene Expression by Cucumber Green Mottle Mosaic Virus Genome-Based Bipartite Vector System

TL;DR

Researchers developed a new virus-based system to improve foreign gene expression in plants, overcoming previous limitations.

Contribution

A novel bipartite vector system based on the CGMMV genome is introduced to enhance foreign gene expression in plants.

Findings

DG-1 requires co-infection with CGMMV to replicate and move within plants.

DG-2 replicates faster and expresses GFP effectively but remains localized.

The bipartite system improves functional genomics in Nicotiana benthamiana.

Abstract

Expanding possibilities for foreign gene expression in cucurbits, we present a novel approach utilising a bipartite vector system based on the cucumber green mottle mosaic virus (CGMMV) genome. Traditional full-length CGMMV vectors face limitations such as a restricted cargo capacity and unstable foreign gene expression. To address these challenges, we developed two ‘deconstructed’ CGMMV genomes, DG-1 and DG-2. DG-1 features a major internal deletion, resulting in the loss of crucial replicase enzyme domains, rendering it incapable of self-replication. However, a staggered infiltration of DG-1 in CGMMV-infected plants enabled successful replication and movement, facilitating gene-silencing experiments. Conversely, DG-2 was engineered to enhance replication rates and provide multiple cloning sites. Although it exhibited higher replication rates, DG-2 remained localised within infiltrated tissue, displaying trans-replication and restricted movement. Notably, DG-2 demonstrated utility in expressing GFP, with a peak expression observed between 6 and 10 days post-infiltration. Overall, our bipartite system represents a significant advancement in functional genomics, offering a robust tool for foreign gene expression in Nicotiana benthamiana.

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