title: MAP kinases phosphorylate rice WRKY45.
abstract: WRKY45 transcription factor is a central regulator of disease resistance mediated by the salicylic acid (SA) signaling pathway in rice. SA-activated WRKY45 protein induces the accumulation of its own mRNA. However, the mechanism underlying this regulation is still unknown. Here, we report three lines of evidence showing that a mitogen-activated protein kinase (MAPK) cascade is involved in this regulation. An inhibitor of MAPK kinase (MAPKK) suppressed the increase in WRKY45 transcript level in response to SA. Two MAPKs, OsMPK4 and OsMPK6, phosphorylated WRKY45 protein in vitro. The activity of OsMPK6 was rapidly upregulated by SA treatment in rice cells. These results suggest that WRKY45 is regulated by MAPK-dependent phosphorylation in the SA pathway.
authors.affiliation: Disease Resistant Crops Research Unit; National Institute of Agrobiological Sciences; Tsukuba, Ibaraki, Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Ueno
authors.forename: Riichiro
authors.initials: R
authors.lastname: Yoshida
authors.forename: Mitsuko
authors.initials: M
authors.lastname: Kishi-Kaboshi
authors.forename: Akane
authors.initials: A
authors.lastname: Matsushita
authors.forename: Chang-Jie
authors.initials: CJ
authors.lastname: Jiang
authors.forename: Shingo
authors.initials: S
authors.lastname: Goto
authors.forename: Akira
authors.initials: A
authors.lastname: Takahashi
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Hirochika
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takatsuji
mesh_terms: D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D012275:Oryza / Q000201:enzymology*; D010766:Phosphorylation; D010940:Plant Proteins / Q000378:metabolism*; D020156:Salicylic Acid / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D010940:Plant Proteins; D020928:Mitogen-Activated Protein Kinases; D020156:Salicylic Acid
keywords: MAPK; disease resistance; phosphorylation; proteasome; rice; salicylic acid