Abstract
The molecular basis for virus-induced disease in plants has been a long-standing mystery. Infection of Arabidopsis by Turnip mosaic virus (TuMV) induces a number of developmental defects in vegetative and reproductive organs. We found that these defects, many of which resemble those in miRNA-deficient dicer-like1 (dcl1) mutants, were due to the TuMV-encoded RNA-silencing suppressor, P1/HC-Pro. Suppression of RNA silencing is a counterdefensive mechanism that enables systemic infection by TuMV. The suppressor interfered with the activity of miR171 (also known as miRNA39), which directs cleavage of several mRNAs coding for Scarecrow-like transcription factors, by inhibiting miR171-guided nucleolytic function. Out of ten other mRNAs that were validated as miRNA-guided cleavage targets, eight accumulated to elevated levels in the presence of P1/HC-Pro. The basis for TuMV- and other virus-induced disease in plants may be explained, at least partly, by interference with miRNA-controlled developmental pathways that share components with the antiviral RNA-silencing pathway.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Arabidopsis / genetics*
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Arabidopsis / metabolism
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Arabidopsis Proteins / genetics
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Arabidopsis Proteins / metabolism
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Blotting, Northern
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Cysteine Endopeptidases / genetics*
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Cysteine Endopeptidases / metabolism
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DNA Primers / chemistry
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Gene Expression Regulation, Developmental
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Gene Expression Regulation, Plant
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Immunoblotting
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MicroRNAs / physiology*
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Microscopy, Electron, Scanning
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Microscopy, Polarization
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Mutagenesis, Site-Directed
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Plant Structures / genetics
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Plant Structures / metabolism
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Plant Structures / virology*
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Plants, Genetically Modified
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Plasmids
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Polymerase Chain Reaction
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RNA Interference / physiology*
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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RNA, Plant / genetics
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RNA, Plant / metabolism
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Tymovirus / pathogenicity*
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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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DNA Primers
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MicroRNAs
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RNA, Messenger
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RNA, Plant
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SCR protein, Arabidopsis
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Viral Proteins
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Cysteine Endopeptidases
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HC-Pro protein, potyvirus