Journal Articles

COBRA-LIKE2, a Member of the Glycosylphosphatidylinositol-Anchored COBRA-LIKE Family, Plays a Role in Cellulose Deposition in Arabidopsis Seed Coat Mucilage Secretory Cells.

March 03, 2015

COBRA-LIKE2, a Member of the Glycosylphosphatidylinositol-Anchored COBRA-LIKE Family, Plays a Role in Cellulose Deposition in Arabidopsis Seed Coat Mucilage Secretory Cells. Plant Physiol. 2015 Mar, Ben-Tov D1, Abraham Y1, Stav S1, Thompson K1, Loraine A1, Elbaum R1, de Souza A1, Pauly M1, Kieber JJ1, Harpaz-Saad S2.

  • 1Robert 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.).
  • 2Robert 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.
  • 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.

    © 2015 American Society of Plant Biologists. All Rights Reserved.

 

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