NRG1, a CC-NB-LRR protein, together with N, a TIR-NB-LRR protein, mediates resistance against tobacco mosaic virus.
In animals and plants, innate immunity is regulated by nucleotide binding domain and leucine-rich repeat (NB-LRR) proteins that mediate pathogen recognition and that activate host-cell defense responses. Plant NB-LRR proteins, referred to as R proteins, have amino-terminal domains that contain a coiled coil (CC) or that share similarity with animal Toll and interleukin 1 receptors (TIR). To investigate R protein function, we are using the TIR-NB-LRR protein N that mediates resistance against tobacco mosaic virus (TMV) through recognition of the TMV p50 protein. Here, we describe N requirement gene 1 (NRG1), a novel N-resistance component that was identified by a virus-induced gene silencing (VIGS) screen of a cDNA library. Surprisingly, NRG1 encodes an NB-LRR type R protein that, in contrast to N, contains a CC rather than a TIR domain. Our findings support emerging evidence that many disease-resistance pathways each recruit more than a single NB-LRR protein. The results also indicate that, in addition to the previously recognized role in elicitor recognition, NB-LRR proteins may also function in downstream signaling pathways.
Peart
Jack R
JR
The Sainsbury Laboratory, John Innes Centre, Norwich, United Kingdom.
Mestre
Pere
P
Lu
Rui
R
Malcuit
Isabelle
I
Baulcombe
David C
DC
D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D040461:Gene Components; D015723:Gene Library; D020868:Gene Silencing; D007113:Immunity, Innate / Q000276:immunology*; D008969:Molecular Sequence Data; D021141:Nucleic Acid Amplification Techniques; D010935:Plant Diseases / Q000821:virology*; D010940:Plant Proteins / Q000235:genetics* / Q000276:immunology; D030821:Plants, Genetically Modified; D015398:Signal Transduction / Q000276:immunology*; D014026:Nicotiana / Q000276:immunology* / Q000821:virology; D014027:Tobacco Mosaic Virus
D018076:DNA, Complementary; D010940:Plant Proteins