title: Selectable marker-free transgenic barley producing a high level of cellulase (1,4-beta-glucanase) in developing grains.
abstract: The use of barley grains as bioreactors for high-level production of cellulase (1,4-beta-glucanase) was investigated. A hybrid cellulase gene, cel-hyb1, driven by the rice GluB-1 promoter was expressed specifically in developing endosperm. Codon usage optimisation of cel-hyb1 increased its expression in barley grains 527-fold and led to cellulase production of up to 1.5% of total grain protein. CEL-HYB1 enzyme in barley grains was highly stable during post-harvest storage. Selectable marker gene ( hph) was subsequently eliminated from transgenic lines through segregation of hph from synthetic cel-hyb1 ( syn.cel-hyb1) in T1 progeny, using a binary plasmid containing hph and syn.cel-hyb1 in separate T-DNAs. These data suggest that barley grains can potentially be used for the commercial production of cellulase.
authors.affiliation: CSIRO Plant Industry, 120 Meiers Road, Indooroopilly, Brisbane, Australia. Gang-Ping.Xue@csiro.au
authors.forename: G P
authors.initials: GP
authors.lastname: Xue
authors.forename: M
authors.initials: M
authors.lastname: Patel
authors.forename: J S
authors.initials: JS
authors.lastname: Johnson
authors.forename: D J
authors.initials: DJ
authors.lastname: Smyth
authors.forename: C E
authors.initials: CE
authors.lastname: Vickers
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002480:Cellulase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004795:Enzyme Stability; D018506:Gene Expression Regulation, Plant; D005819:Genetic Markers; D001467:Hordeum / Q000201:enzymology* / Q000235:genetics*; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D012639:Seeds / Q000201:enzymology / Q000235:genetics
chemical_list: D005819:Genetic Markers; D002480:Cellulase