Initiation of RPS2-specified disease resistance in Arabidopsis is coupled to the AvrRpt2-directed elimination of RIN4.
Plants have evolved a sophisticated innate immune system to recognize invading pathogens and to induce a set of host defense mechanisms resulting in disease resistance. Pathogen recognition is often mediated by plant disease resistance (R) proteins that respond specifically to one or a few pathogen-derived molecules. This specificity has led to suggestions of a receptor-ligand mode of R protein function. Delivery of the bacterial effector protein AvrRpt2 by Pseudomonas syringae specifically induces disease resistance in Arabidopsis plants expressing the RPS2 R protein. We demonstrate that RPS2 physically interacts with Arabidopsis RIN4 and that AvrRpt2 causes the elimination of RIN4 during activation of the RPS2 pathway. AvrRpt2-mediated RIN4 elimination also occurs in the rps2, ndr1, and Atrar1 mutant backgrounds, demonstrating that this activity can be achieved independent of an RPS2-mediated signaling pathway. Therefore, we suggest that RPS2 initiates signaling based upon perception of RIN4 disappearance rather than direct recognition of AvrRpt2.
Axtell
Michael J
MJ
Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
Staskawicz
Brian J
BJ
D000483:Alleles; D017360:Arabidopsis / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D001424:Bacterial Infections / Q000235:genetics / Q000276:immunology*; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000276:immunology; D007113:Immunity, Innate / Q000235:genetics / Q000276:immunology*; D007157:Immunologic Surveillance / Q000235:genetics / Q000276:immunology*; D047908:Intracellular Signaling Peptides and Proteins; D009154:Mutation / Q000235:genetics; D030821:Plants, Genetically Modified / Q000235:genetics / Q000276:immunology; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology
D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; C453279:RIN4 protein, Arabidopsis; C089426:RPS2 protein, Arabidopsis; C420919:avrRpt2 protein, Pseudomonas syringae