title: Formation of polarity convergences underlying shoot outgrowths.
abstract: The development of outgrowths from plant shoots depends on formation of epidermal sites of cell polarity convergence with high intracellular auxin at their centre. A parsimonious model for generation of convergence sites is that cell polarity for the auxin transporter PIN1 orients up auxin gradients, as this spontaneously generates convergent alignments. Here we test predictions of this and other models for the patterns of auxin biosynthesis and import. Live imaging of outgrowths from kanadi1 kanadi2 Arabidopsis mutant leaves shows that they arise by formation of PIN1 convergence sites within a proximodistal polarity field. PIN1 polarities are oriented away from regions of high auxin biosynthesis enzyme expression, and towards regions of high auxin importer expression. Both expression patterns are required for normal outgrowth emergence, and may form part of a common module underlying shoot outgrowths. These findings are more consistent with models that spontaneously generate tandem rather than convergent alignments.
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich, United Kingdom.
authors.forename: Katie
authors.identifier: 0000-0001-5524-6786
authors.initials: K
authors.lastname: Abley
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich, United Kingdom.
authors.forename: Susanna
authors.initials: S
authors.lastname: Sauret-Güeto
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich, United Kingdom.
authors.forename: Athanasius Fm
authors.initials: AF
authors.lastname: Marée
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich, United Kingdom.
authors.forename: Enrico
authors.identifier: 0000-0001-8454-8767
authors.initials: E
authors.lastname: Coen
mesh_terms: D017360:Arabidopsis / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism; D001692:Biological Transport; D016764:Cell Polarity; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism; D008954:Models, Biological; D059828:Plant Cells / Q000378:metabolism / Q000502:physiology*; D019441:Plant Epidermis / Q000378:metabolism / Q000502:physiology*; D018520:Plant Shoots / Q000254:growth & development*
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D026901:Membrane Transport Proteins; C116363:PIN1 protein, Arabidopsis
keywords: A. thaliana; CUC; auxin; developmental biology; leaf development; plant biology; polarity; stem cells