title: AtMYB93 is a novel negative regulator of lateral root development in Arabidopsis.
abstract: Plant root system plasticity is critical for survival in changing environmental conditions. One important aspect of root architecture is lateral root development, a complex process regulated by hormone, environmental and protein signalling pathways. Here we show, using molecular genetic approaches, that the MYB transcription factor AtMYB93 is a novel negative regulator of lateral root development in Arabidopsis. We identify AtMYB93 as an interaction partner of the lateral-root-promoting ARABIDILLO proteins. Atmyb93 mutants have faster lateral root developmental progression and enhanced lateral root densities, while AtMYB93-overexpressing lines display the opposite phenotype. AtMYB93 is expressed strongly, specifically and transiently in the endodermal cells overlying early lateral root primordia and is additionally induced by auxin in the basal meristem of the primary root. Furthermore, Atmyb93 mutant lateral root development is insensitive to auxin, indicating that AtMYB93 is required for normal auxin responses during lateral root development. We propose that AtMYB93 is part of a novel auxin-induced negative feedback loop stimulated in a select few endodermal cells early during lateral root development, ensuring that lateral roots only develop when absolutely required. Putative AtMYB93 homologues are detected throughout flowering plants and represent promising targets for manipulating root systems in diverse crop species.
authors.affiliation: School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Gibbs
authors.affiliation: Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK.
authors.forename: Ute
authors.initials: U
authors.lastname: Voß
authors.affiliation: School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK.
authors.forename: Susan A
authors.initials: SA
authors.lastname: Harding
authors.affiliation: School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK.
authors.forename: Jessica
authors.initials: J
authors.lastname: Fannon
authors.affiliation: School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Moody
authors.affiliation: School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK.
authors.forename: Erika
authors.initials: E
authors.lastname: Yamada
authors.affiliation: Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK.
authors.forename: Kamal
authors.initials: K
authors.lastname: Swarup
authors.affiliation: School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK.
authors.forename: Candida
authors.initials: C
authors.lastname: Nibau
authors.affiliation: School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK.
authors.forename: George W
authors.initials: GW
authors.lastname: Bassel
authors.affiliation: School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK.
authors.forename: Anushree
authors.initials: A
authors.lastname: Choudhary
authors.affiliation: Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK.
authors.forename: Julien
authors.initials: J
authors.lastname: Lavenus
authors.affiliation: School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK.
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Bradshaw
authors.affiliation: School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK.
authors.forename: Dov J
authors.initials: DJ
authors.lastname: Stekel
authors.affiliation: Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK.
authors.forename: Malcolm J
authors.initials: MJ
authors.lastname: Bennett
authors.affiliation: School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK.
authors.forename: Juliet C
authors.initials: JC
authors.lastname: Coates
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000187:drug effects / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D007210:Indoleacetic Acids / Q000494:pharmacology; D018519:Meristem / Q000187:drug effects / Q000254:growth & development; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009928:Organ Specificity / Q000187:drug effects; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding / Q000187:drug effects; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; C000596431:MYB93 protein, Arabidopsis; D014157:Transcription Factors
keywords: ARABIDILLO; MYB; abscisic acid; auxin; endodermis; lateral roots; negative regulation