title: Ethylene upregulates auxin biosynthesis in Arabidopsis seedlings to enhance inhibition of root cell elongation.
abstract: Ethylene represents an important regulatory signal for root development. Genetic studies in Arabidopsis thaliana have demonstrated that ethylene inhibition of root growth involves another hormone signal, auxin. This study investigated why auxin was required by ethylene to regulate root growth. We initially observed that ethylene positively controls auxin biosynthesis in the root apex. We subsequently demonstrated that ethylene-regulated root growth is dependent on (1) the transport of auxin from the root apex via the lateral root cap and (2) auxin responses occurring in multiple elongation zone tissues. Detailed growth studies revealed that the ability of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid to inhibit root cell elongation was significantly enhanced in the presence of auxin. We conclude that by upregulating auxin biosynthesis, ethylene facilitates its ability to inhibit root cell expansion.
authors.affiliation: School of Biosciences and Centre for Plant Integrative Biology, University of Nottingham, LE12 5RD Nottingham, United Kingdom.
authors.forename: Ranjan
authors.initials: R
authors.lastname: Swarup
authors.forename: Paula
authors.initials: P
authors.lastname: Perry
authors.forename: Dik
authors.initials: D
authors.lastname: Hagenbeek
authors.forename: Dominique
authors.initials: D
authors.lastname: Van Der Straeten
authors.forename: Gerrit T S
authors.initials: GT
authors.lastname: Beemster
authors.forename: Göran
authors.initials: G
authors.lastname: Sandberg
authors.forename: Rishikesh
authors.initials: R
authors.lastname: Bhalerao
authors.forename: Karin
authors.initials: K
authors.lastname: Ljung
authors.forename: Malcolm J
authors.initials: MJ
authors.lastname: Bennett
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D005030:Ethylenes / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D005966:Glucuronidase / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism*; D008954:Models, Biological; D018517:Plant Roots / Q000166:cytology* / Q000187:drug effects / Q000254:growth & development; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects*
chemical_list: C100794:AUX1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D005030:Ethylenes; D007210:Indoleacetic Acids; C036216:ethylene; D005966:Glucuronidase