title: The endo-1,4-β-glucanase Korrigan exhibits functional conservation between gymnosperms and angiosperms and is required for proper cell wall formation in gymnosperms.
abstract: The evolution of compositional polymers and their complex arrangement and deposition in the cell walls of terrestrial plants included the acquisition of key protein functions. A membrane-bound endoglucanase, termed Korrigan (KOR), has been shown to be required for proper cellulose synthesis. To date, no extensive characterization of the gymnosperm KOR has been undertaken. Characterization of the white spruce (Picea glauca) gene encoding KOR (PgKOR) shows conserved protein features such as polarized targeting signals and residues predicted to be essential for catalytic activity. The rescue of the Arabidopsis thaliana kor1-1 mutant by the expression of PgKOR suggests gene conservation, providing evidence for functional equivalence. Analyses of endogenous KOR expression in white spruce revealed the highest expression in young developing tissues, which corresponds with primary cell wall development. Additionally, RNA interference of the endogenous gymnosperm gene substantially reduced growth and structural glucose content, but had no effect on cellulose ultrastructure. Partial functional conservation of KOR in gymnosperms suggests that its role in cell wall synthesis dates back to 300 million yr ago (Mya), predating angiosperms, which arose 130 Mya, and shows that proteins contributing to proper cellulose deposition are important conserved features of vascular plants.
authors.affiliation: Department of Wood Science, Faculty of Forestry, The University of British Columbia, 2424 Main Mall, Vancouver, BC, V6T 1Z4 Canada.
authors.forename: Victoria J
authors.initials: VJ
authors.lastname: Maloney
authors.affiliation: Department of Botany, The University of British Columbia, 6270 University Boulevard, Vancouver, BC, V6T 1Z4 Canada.
authors.forename: A Lacey
authors.initials: AL
authors.lastname: Samuels
authors.affiliation: Department of Wood Science, Faculty of Forestry, The University of British Columbia, 2424 Main Mall, Vancouver, BC, V6T 1Z4 Canada.
authors.forename: Shawn D
authors.initials: SD
authors.lastname: Mansfield
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D002473:Cell Wall / Q000737:chemistry / Q000378:metabolism*; D002480:Cellulase / Q000235:genetics* / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism; D017124:Conserved Sequence; D032462:Cycadopsida / Q000201:enzymology* / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D019684:Magnoliopsida / Q000201:enzymology* / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D028222:Picea / Q000166:cytology / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C429844:KOR1 protein, Arabidopsis; D008565:Membrane Proteins; D002482:Cellulose; D002480:Cellulase