title: The cyclophilin A DIAGEOTROPICA gene affects auxin transport in both root and shoot to control lateral root formation.
abstract: Cyclophilin A is a conserved peptidyl-prolyl cis-trans isomerase (PPIase) best known as the cellular receptor of the immunosuppressant cyclosporine A. Despite significant effort, evidence of developmental functions of cyclophilin A in non-plant systems has remained obscure. Mutations in a tomato (Solanum lycopersicum) cyclophilin A ortholog, DIAGEOTROPICA (DGT), have been shown to abolish the organogenesis of lateral roots; however, a mechanistic explanation of the phenotype is lacking. Here, we show that the dgt mutant lacks auxin maxima relevant to priming and specification of lateral root founder cells. DGT is expressed in shoot and root, and localizes to both the nucleus and cytoplasm during lateral root organogenesis. Mutation of ENTIRE/IAA9, a member of the auxin-responsive Aux/IAA protein family of transcriptional repressors, partially restores the inability of dgt to initiate lateral root primordia but not the primordia outgrowth. By comparison, grafting of a wild-type scion restores the process of lateral root formation, consistent with participation of a mobile signal. Antibodies do not detect movement of the DGT protein into the dgt rootstock; however, experiments with radiolabeled auxin and an auxin-specific microelectrode demonstrate abnormal auxin fluxes. Functional studies of DGT in heterologous yeast and tobacco-leaf auxin-transport systems demonstrate that DGT negatively regulates PIN-FORMED (PIN) auxin efflux transporters by affecting their plasma membrane localization. Studies in tomato support complex effects of the dgt mutation on PIN expression level, expression domain and plasma membrane localization. Our data demonstrate that DGT regulates auxin transport in lateral root formation.
authors.affiliation: Oregon State University, Department of Botany and Plant Pathology, 2082 Cordley Hall, Corvallis, OR 97331, USA ivanchem@science.oregonstate.edu.
authors.forename: Maria G
authors.initials: MG
authors.lastname: Ivanchenko
authors.affiliation: University of Fribourg, Department of Biology - Plant Biology, CH-1700 Fribourg, Switzerland.
authors.forename: Jinsheng
authors.initials: J
authors.lastname: Zhu
authors.affiliation: University of Fribourg, Department of Biology - Plant Biology, CH-1700 Fribourg, Switzerland School of Life Sciences, Southwest University, Chongqing 400715, China.
authors.forename: Bangjun
authors.initials: B
authors.lastname: Wang
authors.affiliation: Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg A-3400, Austria.
authors.forename: Eva
authors.initials: E
authors.lastname: Medvecká
authors.affiliation: VIB Department of Plant Systems Biology and Department of Plant Biotechnology and Genetics, Ghent University, Gent 9052, Belgium Key Laboratory of Agro-biodiversity and Pest Management of Education Ministry of China, Yunnan Agricultural University, Kunming 650201, China.
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Du
authors.affiliation: LINV-DIPSAA-Università di Firenze, Viale delle idee 30, Sesto Fiorentino 50019, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Azzarello
authors.affiliation: LINV-DIPSAA-Università di Firenze, Viale delle idee 30, Sesto Fiorentino 50019, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Mancuso
authors.affiliation: Oregon State University, Department of Botany and Plant Pathology, 2082 Cordley Hall, Corvallis, OR 97331, USA.
authors.forename: Molly
authors.initials: M
authors.lastname: Megraw
authors.affiliation: Oregon State University, Department of Botany and Plant Pathology, 2082 Cordley Hall, Corvallis, OR 97331, USA.
authors.forename: Sergei
authors.initials: S
authors.lastname: Filichkin
authors.affiliation: Universidad Nacional Autónoma de México, Instituto de Biotecnología, Departamento de Biología Molecular de Plantas, Apartado Postal 510-3, 62210 Cuernavaca, Morelos, México.
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Dubrovsky
authors.affiliation: Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg A-3400, Austria VIB Department of Plant Systems Biology and Department of Plant Biotechnology and Genetics, Ghent University, Gent 9052, Belgium.
authors.forename: Jiří
authors.initials: J
authors.lastname: Friml
authors.affiliation: University of Fribourg, Department of Biology - Plant Biology, CH-1700 Fribourg, Switzerland.
authors.forename: Markus
authors.initials: M
authors.lastname: Geisler
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D001692:Biological Transport; D021984:Cyclophilin A / Q000235:genetics / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D018520:Plant Shoots / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*
chemical_list: D007210:Indoleacetic Acids; D010940:Plant Proteins; D021984:Cyclophilin A
keywords: Auxin response; Auxin transport; Cyclophilin A; DIAGEOTROPICA; Lateral root initiation