Abstract
Plants and animals sense pathogen-associated molecular patterns (PAMPs) and in turn differentially regulate a subset of microRNAs (miRNAs). However, the extent to which the miRNA pathway contributes to innate immunity remains unknown. Here, we show that miRNA-deficient mutants of Arabidopsis partly restore growth of a type III secretion-defective mutant of Pseudomonas syringae. These mutants also sustained growth of nonpathogenic Pseudomonas fluorescens and Escherichia coli strains, implicating miRNAs as key components of plant basal defense. Accordingly, we have identified P. syringae effectors that suppress transcriptional activation of some PAMP-responsive miRNAs or miRNA biogenesis, stability, or activity. These results provide evidence that, like viruses, bacteria have evolved to suppress RNA silencing to cause disease.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Arabidopsis / genetics
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Arabidopsis / immunology
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Arabidopsis / microbiology*
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Arabidopsis / virology
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Bacterial Proteins / metabolism*
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Escherichia coli / growth & development
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Immunity, Innate
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MicroRNAs / genetics
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MicroRNAs / metabolism*
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Mutation
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Plant Diseases / immunology
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Plant Diseases / microbiology*
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Plant Leaves / metabolism
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Plant Leaves / microbiology
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Plants, Genetically Modified
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Potyvirus / physiology
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Pseudomonas fluorescens / growth & development
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Pseudomonas syringae / genetics
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Pseudomonas syringae / growth & development*
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Pseudomonas syringae / metabolism
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Pseudomonas syringae / pathogenicity
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RNA Interference
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RNA Stability
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RNA, Plant / genetics
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RNA, Plant / metabolism*
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Transcription, Genetic
Substances
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Bacterial Proteins
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MicroRNAs
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RNA, Plant
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avrPto protein, Pseudomonas syringae