Journal Article

Hierarchical Action and Inhibition of Plant Dicer-Like Proteins in Antiviral Defense

Carrington, James C, Bao, Jinsong, Kasschau, Kristin D, Gallego-Bartolome, Javier, Voinnet, Olivier, Deleris, Angélique

2006

Overview

The mechanisms underlying induction and suppression of RNA silencing in the ongoing plant-virus arms race are poorly understood. We show here that virus-derived small RNAs produced by Arabidopsis Dicer-like 4 (DCL4) program an effector complex conferring antiviral immunity. Inhibition of DCL4 by a viral-encoded suppressor revealed the subordinate antiviral activity of DCL2. Accordingly, inactivating both DCL2 and DCL4 was necessary and sufficient to restore systemic infection of a suppressor-deficient virus. The effects of DCL2 were overcome by increasing viral dosage in inoculated leaves, but this could not surmount additional, non-cell autonomous effects of DCL4 specifically preventing viral unloading from the vasculature. These findings define a molecular framework for studying antiviral silencing and defense in plants.

• Publisher: American Association for the Advancement of Science,The American Association for the Advancement of Science,American Association for the Advancement of Science (AAAS)
• Subject: Agronomy. Soil science and plant productions / Antivirals / Arabidopsis / Arabidopsis - enzymology / Arabidopsis - genetics / Arabidopsis - metabolism / Arabidopsis - virology / Arabidopsis Proteins - antagonists & inhibitors / Arabidopsis Proteins - genetics / Arabidopsis Proteins - metabolism / Arabidopsis thaliana / Biochemistry, Molecular Biology / Biological and medical sciences / Carmovirus - physiology / Cell Cycle Proteins - antagonists & inhibitors / Cell Cycle Proteins - genetics / Cell Cycle Proteins - metabolism / Dicer-like 2 protein / Dicer-like 4 protein / Dicer-like proteins / disease resistance / enzyme activity / Fundamental and applied biological sciences. Psychology / gene silencing / Generalities. Techniques. Transmission, epidemiology, ecology. Antiviral substances, control / Genetics and breeding of economic plants / Grants / Green Fluorescent Proteins - metabolism / Infections / Inoculum / Leaves / Life Sciences / Mutation / Pest resistance / Phytopathology. Animal pests. Plant and forest protection / Plant Diseases - virology / plant diseases and disorders / Plant Leaves - virology / Plant pathogens / Plant pathology / Plant Viruses - physiology / Plant viruses and viroids / Plants / Plants, Genetically Modified / Proteins / Recombinant Fusion Proteins - metabolism / resistance mechanisms / Ribonuclease III - antagonists & inhibitors / Ribonuclease III - genetics / Ribonuclease III - metabolism / ribonucleases / Ribonucleases - antagonists & inhibitors / Ribonucleases - genetics / Ribonucleases - metabolism / Ribonucleic acid / RNA / RNA Interference / RNA silencing / RNA Viruses - physiology / RNA, Double-Stranded - metabolism / RNA, Small Interfering - metabolism / RNA, Viral - metabolism / RNA-Induced Silencing Complex - metabolism / RNA-induced silencing complexes / Signal Transduction / Small interfering RNA / Symptoms / Tobacco rattle virus / Turnip crinkle virus / Varietal selection. Specialized plant breeding, plant breeding aims / Viral Proteins - metabolism / Viruses