Involvement of MEK1 MAPKK, NTF6 MAPK, WRKY/MYB transcription factors, COI1 and CTR1 in N-mediated resistance to tobacco mosaic virus.
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.
Liu
Yule
Y
Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA.
Schiff
Michael
M
Dinesh-Kumar
S P
SP
D020868:Gene Silencing; D007113:Immunity, Innate / Q000502:physiology*; D048369:MAP Kinase Kinase 1; D020935:MAP Kinase Signaling System / Q000235:genetics / Q000502:physiology; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D020598:Proto-Oncogene Proteins c-myb / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014027:Tobacco Mosaic Virus / Q000472:pathogenicity*; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D010940:Plant Proteins; D020598:Proto-Oncogene Proteins c-myb; D014157:Transcription Factors; D020928:Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; C429547:Mek1 protein, Nicotiana tabacum; D020929:Mitogen-Activated Protein Kinase Kinases