A Pseudomonas syringae ADP-ribosyltransferase inhibits Arabidopsis mitogen-activated protein kinase kinases.
The successful recognition of pathogen-associated molecular patterns (PAMPs) as a danger signal is crucial for plants to fend off numerous potential pathogenic microbes. The signal is relayed through mitogen-activated protein kinase (MPK) cascades to activate defenses. Here, we show that the Pseudomonas syringae type III effector HopF2 can interact with Arabidopsis thaliana MAP KINASE KINASE5 (MKK5) and likely other MKKs to inhibit MPKs and PAMP-triggered immunity. Inhibition of PAMP-induced MPK phosphorylation was observed when HopF2 was delivered naturally by the bacterial type III secretion system. In addition, HopF2 Arg-71 and Asp-175 residues that are required for the interaction with MKK5 are also necessary for blocking MAP kinase activation, PAMP-triggered defenses, and virulence function in plants. HopF2 can inactivate MKK5 and ADP-ribosylate the C terminus of MKK5 in vitro. Arg-313 of MKK5 is required for ADP-ribosylation by HopF2 and MKK5 function in the plant cell. Together, these results indicate that MKKs are important targets of HopF2.
Wang
Yujing
Y
College of Life Sciences, Beijing Normal University, Beijing 100875, China.
Li
Jifeng
J
Hou
Shuguo
S
Wang
Xingwei
X
Li
Yuan
Y
Ren
Dongtao
D
Chen
She
S
Tang
Xiaoyan
X
Zhou
Jian-Min
JM
D036002:ADP Ribose Transferases / Q000378:metabolism*; D017360:Arabidopsis / Q000201:enzymology* / Q000276:immunology / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors*; D001426:Bacterial Proteins / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors*; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000276:immunology / Q000382:microbiology; D044224:Pseudomonas syringae / Q000201:enzymology* / Q000472:pathogenicity; D014774:Virulence
D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D036002:ADP Ribose Transferases; C519872:MKK5 protein, Arabidopsis; D020929:Mitogen-Activated Protein Kinase Kinases