Abstract
To identify proteins involved in tomato Cf-9 resistance protein function, a yeast two-hybrid screen was undertaken using the cytoplasmic C-terminus of Cf-9 as bait. A thioredoxin-homologous clone, interacting specifically with Cf-9, was identified and called CITRX (Cf-9-interacting thioredoxin). Virus-induced gene silencing (VIGS) of CITRX resulted in an accelerated Cf-9/Avr9-triggered hypersensitive response in both tomato and Nicotiana benthamiana, accompanied by enhanced accumulation of reactive oxygen species, alteration of protein kinase activity and induction of defence-related genes. VIGS of CITRX also conferred increased resistance to the fungal pathogen Cladosporium fulvum in the otherwise susceptible Cf0 tomato. CITRX acts as a negative regulator of the cell death and defence responses induced through Cf-9, but not Cf-2. Recognition of the Cf-9 C-terminus by CITRX is necessary and sufficient for this negative regulation. This is the first study that implicates thioredoxin activity in the regulation of plant disease resistance.
Publication types
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Research Support, Non-U.S. Gov't
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Retracted Publication
MeSH terms
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Amino Acid Sequence
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Base Sequence
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Enzyme Activation
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Gene Expression Regulation, Plant
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Gene Silencing
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Hydrogen Peroxide / metabolism
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Immunity, Innate / genetics
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Immunity, Innate / physiology*
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Membrane Glycoproteins / metabolism*
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Molecular Sequence Data
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Nicotiana / genetics
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Nicotiana / metabolism
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Oxidants / metabolism
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Phylogeny
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Plant Leaves / anatomy & histology
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Plant Leaves / metabolism
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Plant Proteins / classification
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Plant Proteins / genetics
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Plant Proteins / metabolism*
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Plant Viruses / genetics
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Plant Viruses / metabolism
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Protein Kinases / metabolism
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Solanum lycopersicum / chemistry*
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Solanum lycopersicum / genetics
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Thioredoxins / classification
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Thioredoxins / genetics
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Thioredoxins / metabolism*
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Two-Hybrid System Techniques
Substances
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Cf protein, Lycopersicon esculentum
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Membrane Glycoproteins
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Oxidants
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Plant Proteins
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Recombinant Fusion Proteins
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Thioredoxins
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Hydrogen Peroxide
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Protein Kinases
Associated data
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GENBANK/AY500242
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GENBANK/AY500243