Abstract
Pathogen recognition by the plant immune system is governed by structurally related, polymorphic products of disease resistance (R) genes. RAR1 and/or SGT1b mediate the function of many R proteins. RAR1 controls preactivation R protein accumulation by an unknown mechanism. We demonstrate that Arabidopsis SGT1b has two distinct, genetically separable functions in the plant immune system: SGT1b antagonizes RAR1 to negatively regulate R protein accumulation before infection, and SGT1b has a RAR1-independent function that regulates programmed cell death during infection. The balanced activities of RAR1 and SGT1, in concert with cytosolic HSP90, modulate preactivation R protein accumulation and signaling competence.
Publication types
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Apoptosis
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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 / immunology
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Arabidopsis Proteins / physiology*
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Carrier Proteins / antagonists & inhibitors
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Carrier Proteins / immunology
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Carrier Proteins / physiology*
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Cell Cycle Proteins / immunology
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Cell Cycle Proteins / physiology*
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Genes, Plant
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HSP90 Heat-Shock Proteins / immunology
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HSP90 Heat-Shock Proteins / physiology
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Intracellular Signaling Peptides and Proteins
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Mutation
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Peronospora / physiology
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Plant Diseases / microbiology
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Plant Proteins / antagonists & inhibitors
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Plant Proteins / immunology
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Plant Proteins / physiology*
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Plants, Genetically Modified
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Signal Transduction
Substances
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Arabidopsis Proteins
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Carrier Proteins
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Cell Cycle Proteins
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HSP90 Heat-Shock Proteins
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Intracellular Signaling Peptides and Proteins
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PBS2 protein, Arabidopsis
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Plant Proteins
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RPP5 protein, Arabidopsis
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RPP8 protein, Arabidopsis
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RPS5 protein, Arabidopsis
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SGT1b protein, Arabidopsis