title: Characterization of cytokinin signaling and homeostasis gene families in two hardwood tree species: Populus trichocarpa and Prunus persica.
abstract: BACKGROUND
  Through the diversity of cytokinin regulated processes, this phytohormone has a profound impact on plant growth and development. Cytokinin signaling is involved in the control of apical and lateral meristem activity, branching pattern of the shoot, and leaf senescence. These processes influence several traits, including the stem diameter, shoot architecture, and perennial life cycle, which define the development of woody plants. To facilitate research about the role of cytokinin in regulation of woody plant development, we have identified genes associated with cytokinin signaling and homeostasis pathways from two hardwood tree species.
  
  
  RESULTS
  Taking advantage of the sequenced black cottonwood (Populus trichocarpa) and peach (Prunus persica) genomes, we have compiled a comprehensive list of genes involved in these pathways. We identified genes belonging to the six families of cytokinin oxidases (CKXs), isopentenyl transferases (IPTs), LONELY GUY genes (LOGs), two-component receptors, histidine containing phosphotransmitters (HPts), and response regulators (RRs). All together 85 Populus and 45 Prunus genes were identified, and compared to their Arabidopsis orthologs through phylogenetic analyses.
  
  
  CONCLUSIONS
  In general, when compared to Arabidopsis, differences in gene family structure were often seen in only one of the two tree species. However, one class of genes associated with cytokinin signal transduction, the CKI1-like family of two-component histidine kinases, was larger in both Populus and Prunus than in Arabidopsis.
authors.forename: Juha
authors.initials: J
authors.lastname: Immanen
authors.forename: Kaisa
authors.initials: K
authors.lastname: Nieminen
authors.forename: Héctor
authors.initials: H
authors.lastname: Duchens Silva
authors.forename: Fernanda
authors.initials: F
authors.lastname: Rodríguez Rojas
authors.forename: Lee A
authors.initials: LA
authors.lastname: Meisel
authors.forename: Herman
authors.initials: H
authors.lastname: Silva
authors.forename: Victor A
authors.initials: VA
authors.lastname: Albert
authors.forename: Torgeir R
authors.initials: TR
authors.lastname: Hvidsten
authors.affiliation: Institute of Biotechnology and Department of Biosciences, University of Helsinki, FI-00014 Helsinki, Finland. yrjo.helariutta@helsinki.fi.
authors.forename: Ykä
authors.initials: Y
authors.lastname: Helariutta
mesh_terms: D000595:Amino Acid Sequence; D003583:Cytokinins / Q000378:metabolism*; D056426:Genetic Loci; D006706:Homeostasis / Q000235:genetics*; D005810:Multigene Family; D010088:Oxidoreductases / Q000235:genetics; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics; D032107:Populus / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D027861:Prunus / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000235:genetics; D016415:Sequence Alignment; D015398:Signal Transduction
chemical_list: D003583:Cytokinins; D010940:Plant Proteins; D011956:Receptors, Cell Surface; D010088:Oxidoreductases; C019984:cytokinin oxidase