title: Auxin and ethylene are involved in the responses of root system architecture to low boron supply in Arabidopsis seedlings.
abstract: Changes in root architecture are one of the adaptive strategies used by plants to compensate for nutrient deficiencies in soils. In this work, the temporal responses of Arabidopsis (Arabidopsis thaliana) root system architecture to low boron (B) supply were investigated. Arabidopsis Col-0 seedlings were grown in 10 µM B for 5 days and then transferred to a low B medium (0.4 µM) or control medium (10 µM) for a 4-day period. Low B supply caused an inhibition of primary root (PR) growth without altering either the growth or number of lateral roots (LRs). In addition, low B supply induced root hair formation and elongation in positions close to the PR meristem not observed under control conditions. The possible role of auxin and ethylene in the alteration of root system architecture elicited by low B supply was also studied by using two Arabidopsis reporter lines (DR5:GUS and EBS:GUS) and two Arabidopsis mutants with impaired auxin and ethylene signaling (aux1-22 and ein2-1). Low B supply increased auxin reporter DR5:GUS activity in PR tip, suggesting that low B alters the pattern of auxin distribution in PR tip. Moreover, PR elongation in aux1-22 mutant was less sensitive to low B treatment than in wild-type plants, which suggests that auxin resistant 1 (AUX1) participates in the inhibition of PR elongation under low B supply. From all these results, a hypothetical model to explain the effect of low B treatment on PR growth is proposed. We also show that ethylene, via ethylene-insensitive 2 (EIN2) protein, is involved in the induction of root hair formation and elongation under low B treatment.
authors.affiliation: Departamento de Fisiología, Anatomía y Biología Celular, Universidad Pablo de Olavide, E-41013 Sevilla, Spain.
authors.forename: Esperanza M
authors.initials: EM
authors.lastname: Martín-Rejano
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Camacho-Cristóbal
authors.forename: María Begoña
authors.initials: MB
authors.lastname: Herrera-Rodríguez
authors.forename: Jesús
authors.initials: J
authors.lastname: Rexach
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Navarro-Gochicoa
authors.forename: Agustín
authors.initials: A
authors.lastname: González-Fontes
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000254:growth & development* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001895:Boron / Q000378:metabolism / Q000494:pharmacology*; D005030:Ethylenes / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D005966:Glucuronidase; D007210:Indoleacetic Acids / Q000378:metabolism*; D009154:Mutation; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D013997:Time Factors
chemical_list: C100794:AUX1 protein, Arabidopsis; D029681:Arabidopsis Proteins; C119963:EIN2 protein, Arabidopsis; D005030:Ethylenes; D007210:Indoleacetic Acids; D011956:Receptors, Cell Surface; C036216:ethylene; D005966:Glucuronidase; D001895:Boron