title: The Arabidopsis ZED1 pseudokinase is required for ZAR1-mediated immunity induced by the Pseudomonas syringae type III effector HopZ1a.
abstract: Plant and animal pathogenic bacteria can suppress host immunity by injecting type III secreted effector (T3SE) proteins into host cells. However, T3SEs can also elicit host immunity if the host has evolved a means to recognize the presence or activity of specific T3SEs. The diverse YopJ/HopZ/AvrRxv T3SE superfamily, which is found in both animal and plant pathogens, provides examples of T3SEs playing this dual role. The T3SE HopZ1a is an acetyltransferase carried by the phytopathogen Pseudomonas syringae that elicits effector-triggered immunity (ETI) when recognized in Arabidopsis thaliana by the nucleotide-binding leucine-rich repeat (NB-LRR) protein ZAR1. However, recognition of HopZ1a does not require any known ETI-related genes. Using a forward genetics approach, we identify a unique ETI-associated gene that is essential for ZAR1-mediated immunity. The hopZ-ETI-deficient1 (zed1) mutant is specifically impaired in the recognition of HopZ1a, but not the recognition of other unrelated T3SEs or in pattern recognition receptor (PRR)-triggered immunity. ZED1 directly interacts with both HopZ1a and ZAR1 and is acetylated on threonines 125 and 177 by HopZ1a. ZED1 is a nonfunctional kinase that forms part of small genomic cluster of kinases in Arabidopsis. We hypothesize that ZED1 acts as a decoy to lure HopZ1a to the ZAR1-resistance complex, resulting in ETI activation.
authors.affiliation: Department of Cell and Systems Biology and Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON, Canada M5S 3B2.
authors.forename: Jennifer D
authors.initials: JD
authors.lastname: Lewis
authors.forename: Amy Huei-Yi
authors.initials: AH
authors.lastname: Lee
authors.forename: Jana A
authors.initials: JA
authors.lastname: Hassan
authors.forename: Janet
authors.initials: J
authors.lastname: Wan
authors.forename: Brenden
authors.initials: B
authors.lastname: Hurley
authors.forename: Jacquelyn R
authors.initials: JR
authors.lastname: Jhingree
authors.forename: Pauline W
authors.initials: PW
authors.lastname: Wang
authors.forename: Timothy
authors.initials: T
authors.lastname: Lo
authors.forename: Ji-Young
authors.initials: JY
authors.lastname: Youn
authors.forename: David S
authors.initials: DS
authors.lastname: Guttman
authors.forename: Darrell
authors.initials: D
authors.lastname: Desveaux
mesh_terms: D000123:Acetyltransferases / Q000276:immunology* / Q000378:metabolism; D017360:Arabidopsis / Q000201:enzymology* / Q000276:immunology* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D015153:Blotting, Western; D002352:Carrier Proteins / Q000276:immunology* / Q000378:metabolism; D002853:Chromatography, Liquid; D003001:Cloning, Molecular; D016000:Cluster Analysis; D047468:Immunoprecipitation; D010770:Phosphotransferases / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D044224:Pseudomonas syringae / Q000201:enzymology / Q000276:immunology*; D020349:Surface Plasmon Resonance; D053719:Tandem Mass Spectrometry; D020798:Two-Hybrid System Techniques; D047908:Intracellular Signaling Peptides and Proteins
chemical_list: D000123:Acetyltransferases; D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D010770:Phosphotransferases; C551312:ZAR1 protein, Arabidopsis; D047908:Intracellular Signaling Peptides and Proteins; C585493:ZED1 protein, Arabidopsis
keywords: ZED1-related kinase; ZRK; hypersensitive response