title: Cytokinin signaling and its inhibitor AHP6 regulate cell fate during vascular development.
abstract: The cell lineages that form the transporting tissues (xylem and phloem) and the intervening pluripotent procambial tissue originate from stem cells near the root tip. We demonstrate that in Arabidopsis, cytokinin phytohormones negatively regulate protoxylem specification. AHP6, an inhibitory pseudophosphotransfer protein, counteracts cytokinin signaling, allowing protoxylem formation. Conversely, cytokinin signaling negatively regulates the spatial domain of AHP6 expression. Thus, by controlling the identity of cell lineages, the reciprocal interaction of cytokinin signaling and its spatially specific modulator regulates proliferation and differentiation of cell lineages during vascular development, demonstrating a previously unrecognized regulatory circuit underlying meristem organization.
authors.affiliation: Plant Molecular Biology Laboratory, Institute of Biotechnology, POB 56, FI-00014, University of Helsinki, Finland.
authors.forename: Ari Pekka
authors.initials: AP
authors.lastname: Mähönen
authors.forename: Anthony
authors.initials: A
authors.lastname: Bishopp
authors.forename: Masayuki
authors.initials: M
authors.lastname: Higuchi
authors.forename: Kaisa M
authors.initials: KM
authors.lastname: Nieminen
authors.forename: Kaori
authors.initials: K
authors.lastname: Kinoshita
authors.forename: Kirsi
authors.initials: K
authors.lastname: Törmäkangas
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Ikeda
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Oka
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Kakimoto
authors.forename: Ykä
authors.initials: Y
authors.lastname: Helariutta
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000483:Alleles; D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D001593:Benzyl Compounds; D002454:Cell Differentiation; D002455:Cell Division; D019070:Cell Lineage; D003001:Cloning, Molecular; D003583:Cytokinins / Q000378:metabolism*; D017343:Genes, Plant; D007701:Kinetin / Q000378:metabolism / Q000494:pharmacology; D018519:Meristem / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D009024:Morphogenesis; D010641:Phenotype; D010766:Phosphorylation; D010937:Plant Growth Regulators / Q000378:metabolism*; D018517:Plant Roots / Q000166:cytology* / Q000254:growth & development / Q000378:metabolism; D018520:Plant Shoots / Q000378:metabolism; D030821:Plants, Genetically Modified; D011687:Purines; D015398:Signal Transduction; D013489:Suppression, Genetic; D015026:Zeatin / Q000378:metabolism / Q000494:pharmacology
chemical_list: C507179:AHP6 protein, Arabidopsis; D029681:Arabidopsis Proteins; D001593:Benzyl Compounds; D003583:Cytokinins; D010937:Plant Growth Regulators; D011687:Purines; D015026:Zeatin; D000255:Adenosine Triphosphate; C480551:benzylaminopurine; D007701:Kinetin