Harpin induces mitogen-activated protein kinase activity during defence responses in Arabidopsis thaliana suspension cultures.
Elicitation of Arabidopsis thaliana (L.) Heynh. suspension cultures with the bacterial protein harpin (from Pseudomonas syringae pv. syringae) induced the activation of two kinases of 39 and 44 kDa, as demonstrated by in-gel kinase assays using myelin basic protein (MBP) as a substrate. Both these kinases appeared to be tyrosine-phosphorylated upon activation, as demonstrated by treatment with tyrosine phosphatase and immunoprecipitation using an anti-phosphotyrosine monoclonal antibody. An inhibitor of mammalian mitogen-activated protein kinase (MAPK) activation, PD98059, inhibited harpin-induced MBPK activation, but did not inhibit the activity of these kinases. PD98059 also inhibited harpin-induced programmed cell death and defence gene expression, suggesting the involvement of harpin-induced MAPKs in defence responses in Arabidopsis thaliana.
Desikan
R
R
Department of Biological and Biomedical Sciences, University of the West of England, Bristol, Coldharbour Lane, Bristol BS16 1QY, UK.
Clarke
A
A
Atherfold
P
P
Hancock
J T
JT
Neill
S J
SJ
D017209:Apoptosis / Q000187:drug effects; D017360:Arabidopsis / Q000166:cytology / Q000201:enzymology*; D001425:Bacterial Outer Membrane Proteins / Q000494:pharmacology*; D002478:Cells, Cultured; D004789:Enzyme Activation; D004790:Enzyme Induction; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000378:metabolism; D010766:Phosphorylation; D014443:Tyrosine / Q000378:metabolism
D001425:Bacterial Outer Membrane Proteins; D004791:Enzyme Inhibitors; C075462:harpin protein, Erwinia amylovora; C087295:HrpZ protein, Pseudomonas syringae; D014443:Tyrosine; D020928:Mitogen-Activated Protein Kinases