Abstract
RNA interference, mediated by small interfering RNAs (siRNAs), is a conserved regulatory process that has evolved as an antiviral defense mechanism in plants and animals. It is not known whether host cells also use siRNAs as an antibacterial defense mechanism in eukaryotes. Here, we report the discovery of an endogenous siRNA, nat-siRNAATGB2, that is specifically induced by the bacterial pathogen Pseudomonas syringae carrying effector avrRpt2. We demonstrate that the biogenesis of this siRNA requires DCL1, HYL1, HEN1, RDR6, NRPD1A, and SGS3. Its induction also depends on the cognate host disease resistance gene RPS2 and the NDR1 gene that is required for RPS2-specified resistance. This siRNA contributes to RPS2-mediated race-specific disease resistance by repressing PPRL, a putative negative regulator of the RPS2 resistance pathway.
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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Animals
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Arabidopsis / genetics
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Arabidopsis / immunology*
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Arabidopsis / microbiology*
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Arabidopsis Proteins / genetics
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Arabidopsis Proteins / metabolism
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism*
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism
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Plants, Genetically Modified
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Pseudomonas syringae / pathogenicity*
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RNA, Small Interfering / genetics
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RNA, Small Interfering / metabolism*
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RNA-Binding Proteins / genetics
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RNA-Binding Proteins / metabolism
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RNA-Dependent RNA Polymerase / genetics
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RNA-Dependent RNA Polymerase / metabolism
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Ribonuclease III / genetics
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Ribonuclease III / metabolism
Substances
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Arabidopsis Proteins
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Bacterial Proteins
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Cell Cycle Proteins
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HEN1 protein, Arabidopsis
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HYL1 protein, Arabidopsis
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RNA, Small Interfering
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RNA-Binding Proteins
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SGS3 protein, Arabidopsis
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avrRpt2 protein, Pseudomonas syringae
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RDR6 protein, Arabidopsis
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RNA-Dependent RNA Polymerase
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DCL1 protein, Arabidopsis
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Ribonuclease III