Abstract
The tobacco N gene, a member of the Toll-interleukin 1 homology region/nucleotide binding site/leucine-rich repeat (TIR-NBS-LRR) class of resistance (R) genes, confers resistance to tobacco mosaic virus (TMV). We used a candidate gene approach to identify known defense genes that were also involved in N signaling. The requirement for these genes was determined by downregulating their expression using the well-established tobacco rattle virus (TRV)-based virus-induced gene silencing (VIGS). Silencing of genes encoding a mitogen-activated protein kinase (MAPK) NTF6/NRK1, or an MAPK kinase (MAPKK) MEK1/NQK1, attenuated N-mediated resistance to TMV. We also found that N resistance is compromised in plants in which expression of WRKY1-WRKY3 and MYB1 transcription factors were downregulated. In addition, suppression of jasmonic acid (JA) signaling component COI1 ortholog affected N function. However, downregulation of expression of CTR1 ortholog leads to more rapid hypersensitive response (HR). The involvement of these genes in N- and other R-gene-mediated defense provides further evidence for the convergence of downstream signaling pathways of different R genes.
Publication types
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Gene Silencing
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Immunity, Innate / physiology*
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MAP Kinase Kinase 1*
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MAP Kinase Signaling System / genetics
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MAP Kinase Signaling System / physiology
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Mitogen-Activated Protein Kinase Kinases / genetics
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Mitogen-Activated Protein Kinase Kinases / metabolism*
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Mitogen-Activated Protein Kinases / genetics
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Mitogen-Activated Protein Kinases / metabolism*
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Molecular Sequence Data
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Plant Leaves / genetics
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Plant Leaves / metabolism
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Plant Proteins / genetics
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Plant Proteins / metabolism*
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Plants, Genetically Modified / genetics
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Plants, Genetically Modified / metabolism
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Proto-Oncogene Proteins c-myb / genetics
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Proto-Oncogene Proteins c-myb / metabolism*
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Reverse Transcriptase Polymerase Chain Reaction
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Tobacco Mosaic Virus / pathogenicity*
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Transcription Factors / metabolism*
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Transcription, Genetic
Substances
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Plant Proteins
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Proto-Oncogene Proteins c-myb
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Transcription Factors
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Mitogen-Activated Protein Kinases
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MAP Kinase Kinase 1
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Mek1 protein, Nicotiana tabacum
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Mitogen-Activated Protein Kinase Kinases
Associated data
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GENBANK/AY547492
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GENBANK/AY547493
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GENBANK/AY547494
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GENBANK/AY547495
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GENBANK/AY547496
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GENBANK/AY547497
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GENBANK/AY547498