title: Mitogen-activated protein kinase 4-like carrying an MEY motif instead of a TXY motif is involved in ozone tolerance and regulation of stomatal closure in tobacco.
abstract: The mitogen-activated protein kinases (MAPKs/MPKs) are important factors in the regulation of signal transduction in response to biotic and abiotic stresses. Previously, we characterized a MAPK from tobacco, Nicotiana tabacum MPK4 (NtMPK4). Here, we found a highly homologous gene, NtMPK4-like (NtMPK4L), in tobacco as well as other species in Solanaceae and Gramineae. Deduced amino acid sequences of their translation products carried MEY motifs instead of conserved TXY motifs of the MAPK family. We isolated the full length NtMPK4L gene and examined the physiological functions of NtMPK4L. We revealed that NtMPK4L was activated by wounding, like NtMPK4. However, a constitutively active salicylic acid-induced protein kinase kinase (SIPKK(EE)), which phosphorylates NtMPK4, did not phosphorylate NtMPK4L. Moreover, a tyrosine residue in the MEY motif was not involved in NtMPK4L activation. We also found that NtMPK4L-silenced plants showed rapid transpiration caused by remarkably open stomata. In addition, NtMPK4L-silenced plants completely lost the ability to close stomata upon ozone treatment and were highly sensitive to ozone, suggesting that this atypical MAPK plays a role in ozone tolerance through stomatal regulation.
authors.affiliation: Institute of Agrobiological Sciences, NARO, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Yanagawa
authors.affiliation: Institute of Agrobiological Sciences, NARO, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yoda
authors.affiliation: Institute of Agrobiological Sciences, NARO, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Osaki
authors.affiliation: Department of Applied Biological Science, Tokyo University of Science, Noda, Chiba 278-8510, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Amano
authors.affiliation: Environmental Biology Division, National Institute for Environmental Studies, Tsukuba 305-8506, Japan.
authors.forename: Mitsuko
authors.initials: M
authors.lastname: Aono
authors.affiliation: Institute of Agrobiological Sciences, NARO, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
authors.forename: Shigemi
authors.initials: S
authors.lastname: Seo
authors.affiliation: Department of Applied Biological Science, Tokyo University of Science, Noda, Chiba 278-8510, Japan Imaging Frontier Center, Tokyo University of Science, Noda, Chiba 278-8510, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Kuchitsu
authors.affiliation: Institute of Agrobiological Sciences, NARO, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan mituhara@affrc.go.jp.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Mitsuhara
mesh_terms: D000595:Amino Acid Sequence; D018506:Gene Expression Regulation, Plant; D020928:Mitogen-Activated Protein Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010126:Ozone / Q000378:metabolism*; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D054046:Plant Stomata / Q000378:metabolism*; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D010126:Ozone; D020928:Mitogen-Activated Protein Kinases
keywords: MAP kinase; MPK4; Nicotiana; TEY motif.; ozone; stomata; tabacum