title: Timing is everything: highly specific and transient expression of a MAP kinase determines auxin-induced leaf venation patterns in Arabidopsis.
abstract: Mitogen-activated protein kinase (MAPK) cascades are universal signal transduction modules present in all eukaryotes. In plants, MAPK cascades were shown to regulate cell division, developmental processes, stress responses, and hormone pathways. The subgroup A of Arabidopsis MAPKs consists of AtMPK3, AtMPK6, and AtMPK10. AtMPK3 and AtMPK6 are activated by their upstream MAP kinase kinases (MKKs) AtMKK4 and AtMKK5 in response to biotic and abiotic stress. In addition, they were identified as key regulators of stomatal development and patterning. AtMPK10 has long been considered as a pseudo-gene, derived from a gene duplication of AtMPK6. Here we show that AtMPK10 is expressed highly but very transiently in seedlings and at sites of local auxin maxima leaves. MPK10 encodes a functional kinase and interacts with the upstream MAP kinase kinase (MAPKK) AtMKK2. mpk10 mutants are delayed in flowering in long-day conditions and in continuous light. Moreover, cotyledons of mpk10 and mkk2 mutants have reduced vein complexity, which can be reversed by inhibiting polar auxin transport (PAT). Auxin does not affect AtMPK10 expression while treatment with the PAT inhibitor HFCA extends the expression in leaves and reverses the mpk10 mutant phenotype. These results suggest that the AtMKK2-AtMPK10 MAPK module regulates venation complexity by altering PAT efficiency.
authors: Department of Plant Molecular Biology, Max. F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9/4, Vienna, A-1030, Austria; Present address: Felix-Klein-Gymnasium, Böttingerstraße 17, D-37073 Göttingen, Germany.
authors: Vera
authors: V
authors: Stanko
authors: Department of Plant Molecular Biology, Max. F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9/4, Vienna, A-1030, Austria; Present address: Austrian Centre of Industrial Biotechnology, Muthgasse 11, A-1190 Vienna, Austria.
authors: Concetta
authors: C
authors: Giuliani
authors: Department of Plant Molecular Biology, Max. F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9/4, Vienna, A-1030, Austria; Present address: Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria.
authors: Katarzyna
authors: K
authors: Retzer
authors: Department of Plant Molecular Biology, Max. F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9/4, Vienna, A-1030, Austria; Present address: Gregor Mendel Institute of Molecular Plant Biology, Dr. Bohr-Gasse 3, 1030 Vienna, Austria.
authors: Armin
authors: A
authors: Djamei
authors: Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany.
authors: Vanessa
authors: V
authors: Wahl
authors: Department of Biochemistry, Max. F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9/5, Vienna, A-1030, Austria; Present address: Department of Ecogenomics and Systems Biology, University of Vienna, Althanstr. 14, A-1090 Vienna, Austria.
authors: Bernhard
authors: B
authors: Wurzinger
authors: Department of Plant Molecular Biology, Max. F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9/4, Vienna, A-1030, Austria; Present address: Telethon Institute of Genetics and Medicine, Via Pietro Castellino, 111, 80131-Naples, Italy.
authors: Cathal
authors: C
authors: Wilson
authors: Department of Plant Molecular Biology, Max. F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9/4, Vienna, A-1030, Austria.
authors: Erwin
authors: E
authors: Heberle-Bors
authors: Department of Biochemistry, Max. F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9/5, Vienna, A-1030, Austria; Department of Ecogenomics and Systems Biology, University of Vienna, Althanstr. 14, A-1090 Vienna, Austria. Electronic address: markus.teige@univie.ac.at.
authors: Markus
authors: M
authors: Teige
authors: Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany; Department of Biochemistry, Max. F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9/5, Vienna, A-1030, Austria. Electronic address: kragler@mpimp-golm.mpg.de.
authors: Friedrich
authors: F
authors: Kragler
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D018515:Plant Leaves / Q000033:anatomy & histology*; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; C488959:MKK2 protein, Arabidopsis; D020929:Mitogen-Activated Protein Kinase Kinases
keywords: Arabidopsis MAP kinase; leaf development; leaf venation pattern.; polar auxin transport