title: OCTOPUS, a polarly localised membrane-associated protein, regulates phloem differentiation entry in Arabidopsis thaliana.
abstract: Vascular development is embedded into the developmental context of plant organ differentiation and can be divided into the consecutive phases of vascular patterning and differentiation of specific vascular cell types (phloem and xylem). To date, only very few genetic determinants of phloem development are known. Here, we identify OCTOPUS (OPS) as a potentiator of phloem differentiation. OPS is a polarly localised membrane-associated protein that is initially expressed in provascular cells, and upon vascular cell type specification becomes restricted to the phloem cell lineage. OPS mutants display a reduction of cotyledon vascular pattern complexity and discontinuous phloem differentiation, whereas OPS overexpressers show accelerated progress of cotyledon vascular patterning and phloem differentiation. We propose that OPS participates in vascular differentiation by interpreting longitudinal signals that lead to the transformation of vascular initials into differentiating protophloem cells.
authors.affiliation: INRA, UMR1318, Institut Jean-Pierre Bourgin, Versailles, France. etruerni@ethz.ch
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Truernit
authors.forename: Hélène
authors.initials: H
authors.lastname: Bauby
authors.forename: Katia
authors.initials: K
authors.lastname: Belcram
authors.forename: Julien
authors.initials: J
authors.lastname: Barthélémy
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Palauqui
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008565:Membrane Proteins / Q000502:physiology*; D018613:Microscopy, Confocal / Q000379:methods; D009154:Mutation; D010641:Phenotype; D052585:Phloem / Q000378:metabolism; D018521:Plant Physiological Phenomena; D018517:Plant Roots / Q000378:metabolism; D011401:Promoter Regions, Genetic; D013997:Time Factors
chemical_list: D029681:Arabidopsis Proteins; D008565:Membrane Proteins; C571839:OCTOPUS protein, Arabidopsis