title: The epidermis-specific extracellular BODYGUARD controls cuticle development and morphogenesis in Arabidopsis.
abstract: The outermost epidermal cell wall is specialized to withstand pathogens and natural stresses, and lipid-based cuticular polymers are the major barrier against incursions. The Arabidopsis thaliana mutant bodyguard (bdg), which exhibits defects characteristic of the loss of cuticle structure not attributable to a lack of typical cutin monomers, unexpectedly accumulates significantly more cell wall-bound lipids and epicuticular waxes than wild-type plants. Pleiotropic effects of the bdg mutation on growth, viability, and cell differentiation are also observed. BDG encodes a member of the alpha/beta-hydrolase fold protein superfamily and is expressed exclusively in epidermal cells. Using Strep-tag epitope-tagged BDG for mutant complementation and immunolocalization, we show that BDG is a polarly localized protein that accumulates in the outermost cell wall in the epidermis. With regard to the appearance and structure of the cuticle, the phenotype conferred by bdg is reminiscent of that of transgenic Arabidopsis plants that express an extracellular fungal cutinase, suggesting that bdg may be incapable of completing the polymerization of carboxylic esters in the cuticular layer of the cell wall or the cuticle proper. We propose that BDG codes for an extracellular synthase responsible for the formation of cuticle. The alternative hypothesis proposes that BDG controls the proliferation/differentiation status of the epidermis via an unknown mechanism.
authors.affiliation: Max-Planck-Institut für Züchtungsforschung, 50829 Köln, Germany.
authors.forename: Sergey
authors.initials: S
authors.lastname: Kurdyukov
authors.forename: Andrea
authors.initials: A
authors.lastname: Faust
authors.forename: Christiane
authors.initials: C
authors.lastname: Nawrath
authors.forename: Sascha
authors.initials: S
authors.lastname: Bär
authors.forename: Derry
authors.initials: D
authors.lastname: Voisin
authors.forename: Nadia
authors.initials: N
authors.lastname: Efremova
authors.forename: Rochus
authors.initials: R
authors.lastname: Franke
authors.forename: Lukas
authors.initials: L
authors.lastname: Schreiber
authors.forename: Heinz
authors.initials: H
authors.lastname: Saedler
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Métraux
authors.forename: Alexander
authors.initials: A
authors.lastname: Yephremov
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000033:anatomy & histology / Q000254:growth & development* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D004251:DNA Transposable Elements / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D006867:Hydrolases / Q000737:chemistry; D008055:Lipids / Q000032:analysis; D008969:Molecular Sequence Data; D009024:Morphogenesis; D009928:Organ Specificity; D010641:Phenotype; D019441:Plant Epidermis / Q000254:growth & development* / Q000378:metabolism* / Q000648:ultrastructure; D018515:Plant Leaves / Q000033:anatomy & histology / Q000648:ultrastructure; D030821:Plants, Genetically Modified / Q000378:metabolism; D050050:Protein Carbonylation; D017510:Protein Folding; D021381:Protein Transport; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014885:Waxes / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C512167:BDG protein, Arabidopsis; D004251:DNA Transposable Elements; D008055:Lipids; D012333:RNA, Messenger; D014885:Waxes; D006867:Hydrolases