Abstract
Cross-protection triggered by a mild strain of virus acts as a prophylaxis to prevent subsequent infections by related viruses in plants; however, the underling mechanisms are not fully understood. Through mutagenesis, we isolated a mutant strain of Turnip mosaic virus (TuMV), named Tu-GK, that contains an Arg182Lys substitution in helper component-proteinase (HC-Pro(K)) that confers complete cross-protection against infection by a severe strain of TuMV in Nicotiana benthamiana, Arabidopsis thaliana Col-0, and the Arabidopsis dcl2-4/dcl4-1 double mutant defective in DICER-like ribonuclease (DCL)2/DCL4-mediated silencing. Our analyses showed that HC-Pro(K) loses the ability to interfere with microRNA pathways, although it retains a partial capability for RNA silencing suppression triggered by DCL. We further showed that Tu-GK infection triggers strong salicylic acid (SA)-dependent and SA-independent innate immunity responses. Our data suggest that DCL2/4-dependent and -independent RNA silencing pathways are involved, and may crosstalk with basal innate immunity pathways, in host defense and in cross-protection.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Motifs
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Amino Acid Substitution
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Arabidopsis / immunology
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Arabidopsis / virology
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Arabidopsis Proteins / genetics*
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Arabidopsis Proteins / metabolism
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Cell Cycle Proteins / genetics*
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Cell Cycle Proteins / metabolism
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Cross Protection*
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Cysteine Endopeptidases / genetics*
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Cysteine Endopeptidases / metabolism
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Gene Expression Regulation, Plant
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High-Throughput Nucleotide Sequencing
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MicroRNAs / genetics
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Models, Biological
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Mutation
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Nicotiana / immunology
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Nicotiana / virology
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Plant Diseases / immunology*
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Plant Diseases / virology
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Plant Leaves / immunology
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Plant Leaves / virology
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Plants, Genetically Modified
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Potyvirus / genetics*
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Potyvirus / physiology
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RNA Interference
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Ribonuclease III / genetics*
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Ribonuclease III / metabolism
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Salicylic Acid / metabolism
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Seedlings / immunology
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Seedlings / virology
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Sequence Analysis, RNA
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Viral Proteins / genetics*
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Viral Proteins / metabolism
Substances
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Arabidopsis Proteins
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Cell Cycle Proteins
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MicroRNAs
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Viral Proteins
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DCL4 protein, Arabidopsis
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DCL2 protein, Arabidopsis
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Ribonuclease III
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Cysteine Endopeptidases
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HC-Pro protein, potyvirus
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Salicylic Acid
Associated data
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SRA/SRR1262389
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SRA/SRR1262545
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SRA/SRR1262546
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SRA/SRR1262601