Nuclear accumulation of the Arabidopsis immune receptor RPS4 is necessary for triggering EDS1-dependent defense.
Recognition of specific pathogen molecules inside the cell by nucleotide-binding domain and leucine-rich repeat (NB-LRR) receptors constitutes an important layer of innate immunity in plants. Receptor activation triggers host cellular reprogramming involving transcriptional potentiation of basal defenses and localized programmed cell death. The sites and modes of action of NB-LRR receptors are, however, poorly understood. Arabidopsis Toll/Interleukin-1 (TIR) type NB-LRR receptor RPS4 recognizes the bacterial type III effector AvrRps4. We show that epitope-tagged RPS4 expressed under its native regulatory sequences distributes between endomembranes and nuclei in healthy and AvrRps4-triggered tissues. RPS4 accumulation in the nucleus, mediated by a bipartite nuclear localization sequence (NLS) at its C terminus, is necessary for triggering immunity through authentic activation by AvrRps4 in Arabidopsis or as an effector-independent "deregulated" receptor in tobacco. A strikingly conserved feature of TIR-NB-LRR receptors is their recruitment of the nucleocytoplasmic basal-defense regulator EDS1 in resistance to diverse pathogens. We find that EDS1 is an indispensable component of RPS4 signaling and that it functions downstream of RPS4 activation but upstream of RPS4-mediated transcriptional reprogramming in the nucleus.
Wirthmueller
Lennart
L
Department of Plant-Microbe Interactions, Max-Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany.
Zhang
Yan
Y
Jones
Jonathan D G
JD
Parker
Jane E
JE
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D019913:Nuclear Localization Signals; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D044224:Pseudomonas syringae / Q000235:genetics / Q000378:metabolism; D012231:Rhizobium / Q000472:pathogenicity; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism / Q000382:microbiology
D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C118837:EDS1 protein, Arabidopsis; D019913:Nuclear Localization Signals; D010940:Plant Proteins; C097421:rps4 protein, plant