title: COBRA-LIKE2, a member of the glycosylphosphatidylinositol-anchored COBRA-LIKE family, plays a role in cellulose deposition in arabidopsis seed coat mucilage secretory cells.
abstract: Differentiation of the maternally derived seed coat epidermal cells into mucilage secretory cells is a common adaptation in angiosperms. Recent studies identified cellulose as an important component of seed mucilage in various species. Cellulose is deposited as a set of rays that radiate from the seed upon mucilage extrusion, serving to anchor the pectic component of seed mucilage to the seed surface. Using transcriptome data encompassing the course of seed development, we identified COBRA-LIKE2 (COBL2), a member of the glycosylphosphatidylinositol-anchored COBRA-LIKE gene family in Arabidopsis (Arabidopsis thaliana), as coexpressed with other genes involved in cellulose deposition in mucilage secretory cells. Disruption of the COBL2 gene results in substantial reduction in the rays of cellulose present in seed mucilage, along with an increased solubility of the pectic component of the mucilage. Light birefringence demonstrates a substantial decrease in crystalline cellulose deposition into the cellulosic rays of the cobl2 mutants. Moreover, crystalline cellulose deposition into the radial cell walls and the columella appears substantially compromised, as demonstrated by scanning electron microscopy and in situ quantification of light birefringence. Overall, the cobl2 mutants display about 40% reduction in whole-seed crystalline cellulose content compared with the wild type. These data establish that COBL2 plays a role in the deposition of crystalline cellulose into various secondary cell wall structures during seed coat epidermal cell differentiation.
authors.affiliation: Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University, Rehovot 76100, Israel (D.B.-T., Y.A., R.E., S.H.-S.);Department of Bioinformatics and Genomics, University of North Carolina, Kannapolis, North Carolina 28081 (S.S., K.T., A.L.);Energy Biosciences Institute (A.d.S., M.P.) and Department of Plant and Microbial Biology (M.P.), University of California, Berkeley, California 94720; andBiology Department, University of North Carolina, Chapel Hill, North Carolina 27599 (J.J.K.).
authors.forename: Daniela
authors.initials: D
authors.lastname: Ben-Tov
authors.affiliation: Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University, Rehovot 76100, Israel (D.B.-T., Y.A., R.E., S.H.-S.);Department of Bioinformatics and Genomics, University of North Carolina, Kannapolis, North Carolina 28081 (S.S., K.T., A.L.);Energy Biosciences Institute (A.d.S., M.P.) and Department of Plant and Microbial Biology (M.P.), University of California, Berkeley, California 94720; andBiology Department, University of North Carolina, Chapel Hill, North Carolina 27599 (J.J.K.).
authors.forename: Yael
authors.initials: Y
authors.lastname: Abraham
authors.affiliation: Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University, Rehovot 76100, Israel (D.B.-T., Y.A., R.E., S.H.-S.);Department of Bioinformatics and Genomics, University of North Carolina, Kannapolis, North Carolina 28081 (S.S., K.T., A.L.);Energy Biosciences Institute (A.d.S., M.P.) and Department of Plant and Microbial Biology (M.P.), University of California, Berkeley, California 94720; andBiology Department, University of North Carolina, Chapel Hill, North Carolina 27599 (J.J.K.).
authors.forename: Shira
authors.initials: S
authors.lastname: Stav
authors.affiliation: Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University, Rehovot 76100, Israel (D.B.-T., Y.A., R.E., S.H.-S.);Department of Bioinformatics and Genomics, University of North Carolina, Kannapolis, North Carolina 28081 (S.S., K.T., A.L.);Energy Biosciences Institute (A.d.S., M.P.) and Department of Plant and Microbial Biology (M.P.), University of California, Berkeley, California 94720; andBiology Department, University of North Carolina, Chapel Hill, North Carolina 27599 (J.J.K.).
authors.forename: Kevin
authors.initials: K
authors.lastname: Thompson
authors.affiliation: Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University, Rehovot 76100, Israel (D.B.-T., Y.A., R.E., S.H.-S.);Department of Bioinformatics and Genomics, University of North Carolina, Kannapolis, North Carolina 28081 (S.S., K.T., A.L.);Energy Biosciences Institute (A.d.S., M.P.) and Department of Plant and Microbial Biology (M.P.), University of California, Berkeley, California 94720; andBiology Department, University of North Carolina, Chapel Hill, North Carolina 27599 (J.J.K.).
authors.forename: Ann
authors.initials: A
authors.lastname: Loraine
authors.affiliation: Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University, Rehovot 76100, Israel (D.B.-T., Y.A., R.E., S.H.-S.);Department of Bioinformatics and Genomics, University of North Carolina, Kannapolis, North Carolina 28081 (S.S., K.T., A.L.);Energy Biosciences Institute (A.d.S., M.P.) and Department of Plant and Microbial Biology (M.P.), University of California, Berkeley, California 94720; andBiology Department, University of North Carolina, Chapel Hill, North Carolina 27599 (J.J.K.).
authors.forename: Rivka
authors.initials: R
authors.lastname: Elbaum
authors.affiliation: Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University, Rehovot 76100, Israel (D.B.-T., Y.A., R.E., S.H.-S.);Department of Bioinformatics and Genomics, University of North Carolina, Kannapolis, North Carolina 28081 (S.S., K.T., A.L.);Energy Biosciences Institute (A.d.S., M.P.) and Department of Plant and Microbial Biology (M.P.), University of California, Berkeley, California 94720; andBiology Department, University of North Carolina, Chapel Hill, North Carolina 27599 (J.J.K.).
authors.forename: Amancio
authors.initials: A
authors.lastname: de Souza
authors.affiliation: Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University, Rehovot 76100, Israel (D.B.-T., Y.A., R.E., S.H.-S.);Department of Bioinformatics and Genomics, University of North Carolina, Kannapolis, North Carolina 28081 (S.S., K.T., A.L.);Energy Biosciences Institute (A.d.S., M.P.) and Department of Plant and Microbial Biology (M.P.), University of California, Berkeley, California 94720; andBiology Department, University of North Carolina, Chapel Hill, North Carolina 27599 (J.J.K.).
authors.forename: Markus
authors.initials: M
authors.lastname: Pauly
authors.affiliation: Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University, Rehovot 76100, Israel (D.B.-T., Y.A., R.E., S.H.-S.);Department of Bioinformatics and Genomics, University of North Carolina, Kannapolis, North Carolina 28081 (S.S., K.T., A.L.);Energy Biosciences Institute (A.d.S., M.P.) and Department of Plant and Microbial Biology (M.P.), University of California, Berkeley, California 94720; andBiology Department, University of North Carolina, Chapel Hill, North Carolina 27599 (J.J.K.).
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Kieber
authors.affiliation: Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University, Rehovot 76100, Israel (D.B.-T., Y.A., R.E., S.H.-S.);Department of Bioinformatics and Genomics, University of North Carolina, Kannapolis, North Carolina 28081 (S.S., K.T., A.L.);Energy Biosciences Institute (A.d.S., M.P.) and Department of Plant and Microbial Biology (M.P.), University of California, Berkeley, California 94720; andBiology Department, University of North Carolina, Chapel Hill, North Carolina 27599 (J.J.K.) smadar.harpaz@mail.huji.ac.il.
authors.forename: Smadar
authors.initials: S
authors.lastname: Harpaz-Saad
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001718:Birefringence; D002412:Cations; D002454:Cell Differentiation / Q000187:drug effects; D002473:Cell Wall / Q000187:drug effects / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism*; D002614:Chelating Agents / Q000494:pharmacology; D003460:Crystallization; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009928:Organ Specificity / Q000187:drug effects; D010368:Pectins / Q000378:metabolism; D019441:Plant Epidermis / Q000166:cytology / Q000187:drug effects; D062087:Plant Mucilage / Q000378:metabolism; D012639:Seeds / Q000166:cytology* / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D012995:Solubility
chemical_list: D029681:Arabidopsis Proteins; C000604243:COBL2 protein, Arabidopsis; D002412:Cations; D002614:Chelating Agents; D017261:Glycosylphosphatidylinositols; D008565:Membrane Proteins; D062087:Plant Mucilage; D010368:Pectins; D002482:Cellulose