title: The Dehydratase ADT3 Affects ROS Homeostasis and Cotyledon Development.
abstract: During the transition from seed to seedling, emerging embryos strategically balance available resources between building up defenses against environmental threats and initiating the developmental program that promotes the switch to autotrophy. We present evidence of a critical role for the phenylalanine (Phe) biosynthetic activity of AROGENATE DEHYDRATASE3 (ADT3) in coordinating reactive oxygen species (ROS) homeostasis and cotyledon development in etiolated Arabidopsis (Arabidopsis thaliana) seedlings. We show that ADT3 is expressed in the cotyledon and shoot apical meristem, mainly in the cytosol, and that the epidermis of adt3 cotyledons contains higher levels of ROS Genome-wide proteomics of the adt3 mutant revealed a general down-regulation of plastidic proteins and ROS-scavenging enzymes, corroborating the hypothesis that the ADT3 supply of Phe is required to control ROS concentration and distribution to protect cellular components. In addition, loss of ADT3 disrupts cotyledon epidermal patterning by affecting the number and expansion of pavement cells and stomata cell fate specification; we also observed severe alterations in mesophyll cells, which lack oil bodies and normal plastids. Interestingly, up-regulation of the pathway leading to cuticle production is accompanied by an abnormal cuticle structure and/or deposition in the adt3 mutant. Such impairment results in an increase in cell permeability and provides a link to understand the cell defects in the adt3 cotyledon epidermis. We suggest an additional role of Phe in supplying nutrients to the young seedling.
authors.affiliation: Weinberg College of Art and Science, Northwestern University, Evanston, Illinois 60208 (A.P.);Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607 (D.M., D.A.O.-N., R.M., K.M.W.); andProteomics and Mass Spectrometry Facility, Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (S.A., M.J.N.).
authors.forename: Alessia
authors.initials: A
authors.lastname: Para
authors.affiliation: Weinberg College of Art and Science, Northwestern University, Evanston, Illinois 60208 (A.P.);Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607 (D.M., D.A.O.-N., R.M., K.M.W.); andProteomics and Mass Spectrometry Facility, Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (S.A., M.J.N.).
authors.forename: DurreShahwar
authors.initials: D
authors.lastname: Muhammad
authors.affiliation: Weinberg College of Art and Science, Northwestern University, Evanston, Illinois 60208 (A.P.);Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607 (D.M., D.A.O.-N., R.M., K.M.W.); andProteomics and Mass Spectrometry Facility, Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (S.A., M.J.N.).
authors.forename: Danielle A
authors.identifier: 0000-0003-3381-0504
authors.initials: DA
authors.lastname: Orozco-Nunnelly
authors.affiliation: Weinberg College of Art and Science, Northwestern University, Evanston, Illinois 60208 (A.P.);Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607 (D.M., D.A.O.-N., R.M., K.M.W.); andProteomics and Mass Spectrometry Facility, Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (S.A., M.J.N.).
authors.forename: Ramis
authors.identifier: 0000-0001-7662-2437
authors.initials: R
authors.lastname: Memishi
authors.affiliation: Weinberg College of Art and Science, Northwestern University, Evanston, Illinois 60208 (A.P.);Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607 (D.M., D.A.O.-N., R.M., K.M.W.); andProteomics and Mass Spectrometry Facility, Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (S.A., M.J.N.).
authors.forename: Sophie
authors.identifier: 0000-0001-8550-2832
authors.initials: S
authors.lastname: Alvarez
authors.affiliation: Weinberg College of Art and Science, Northwestern University, Evanston, Illinois 60208 (A.P.);Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607 (D.M., D.A.O.-N., R.M., K.M.W.); andProteomics and Mass Spectrometry Facility, Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (S.A., M.J.N.).
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Naldrett
authors.affiliation: Weinberg College of Art and Science, Northwestern University, Evanston, Illinois 60208 (A.P.);Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607 (D.M., D.A.O.-N., R.M., K.M.W.); andProteomics and Mass Spectrometry Facility, Donald Danforth Plant Science Center, St. Louis, Missouri 63132 (S.A., M.J.N.) kwarpeha@uic.edu.
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Warpeha
mesh_terms: D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002853:Chromatography, Liquid; D018548:Cotyledon / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D006706:Homeostasis; D018519:Meristem / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D058503:Mesophyll Cells / Q000378:metabolism / Q000648:ultrastructure; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D009154:Mutation; D010649:Phenylalanine / Q000378:metabolism; D019441:Plant Epidermis / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D030821:Plants, Genetically Modified; D011303:Prephenate Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D020543:Proteome / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D036226:Seedlings / Q000254:growth & development / Q000378:metabolism; D012639:Seeds / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D053719:Tandem Mass Spectrometry
chemical_list: D029681:Arabidopsis Proteins; D020543:Proteome; D017382:Reactive Oxygen Species; D010649:Phenylalanine; D011303:Prephenate Dehydrogenase; C027017:cyclohexadienyl dehydrogenase