Phloem-Triggered Virus-Induced Gene Silencing Using a Recombinant Polerovirus

Area of Science:

• Plant virology
• Molecular biology
• Functional genomics

Background:

• Phloem-limited poleroviruses infect Arabidopsis thaliana asymptomatically.
• Visual identification of these infections is challenging.
• Virus-induced gene silencing (VIGS) offers a potential solution for gene silencing and visual tracking.

Purpose of the Study:

• To develop and characterize VIGS vectors derived from Turnip yellows virus (TuYV) for efficient gene silencing in Arabidopsis thaliana.
• To assess the effectiveness of different sequence insertions and the role of the TuYV P0 protein in VIGS.
• To demonstrate the utility of TuYV-based VIGS for studying phloem-restricted genes.

Main Methods:

• Construction of recombinant TuYV vectors containing sense, antisense, or inverted-repeat (IR) sequences of the Arabidopsis CHLI1 gene.
• Infection of Arabidopsis thaliana with recombinant TuYV and observation of phenotypes (vein chlorosis).
• Introduction of a P0 knock-out mutation into TuYV vectors to evaluate its impact on VIGS and viral accumulation.
• Silencing of the phloem-specific gene AtRTM1 using TuYV-derived VIGS vectors.

Main Results:

• All recombinant TuYV viruses induced vein chlorosis in Arabidopsis, indicating successful silencing of AtCHLI1.
• Sense-oriented sequence insertions resulted in more sustainable chlorosis and higher stability compared to IR insertions.
• The TuYV P0 protein did not hinder VIGS efficiency, although its absence led to milder phenotypes due to lower viral accumulation.
• TuYV-derived VIGS vectors effectively silenced the phloem-specific AtRTM1 gene.

Conclusions:

• TuYV-based VIGS vectors are powerful tools for visual detection and monitoring of TuYV infections in plants.
• These vectors facilitate functional analysis of phloem-restricted genes in Arabidopsis.
• Poleroviruses hold significant potential for functional genomic studies in various agronomic plants.