title: The cell wall and secretory proteome of a tobacco cell line synthesising secondary wall.
abstract: The utility of plant secondary cell wall biomass for industrial and biofuel purposes depends upon improving cellulose amount, availability and extractability. The possibility of engineering such biomass requires much more knowledge of the genes and proteins involved in the synthesis, modification and assembly of cellulose, lignin and xylans. Proteomic data are essential to aid gene annotation and understanding of polymer biosynthesis. Comparative proteomes were determined for secondary walls of stem xylem and transgenic xylogenic cells of tobacco and detected peroxidase, cellulase, chitinase, pectinesterase and a number of defence/cell death related proteins, but not marker proteins of primary walls such as xyloglucan endotransglycosidase and expansins. Only the corresponding detergent soluble proteome of secretory microsomes from the xylogenic cultured cells, subjected to ion-exchange chromatography, could be determined accurately since, xylem-specific membrane yields were of poor quality from stem tissue. Among the 109 proteins analysed, many of the protein markers of the ER such as BiP, HSP70, calreticulin and calnexin were identified, together with some of the biosynthetic enzymes and associated polypeptides involved in polymer synthesis. However 53% of these endomembrane proteins failed identification despite the use of two different MS methods, leaving considerable possibilities for future identification of novel proteins involved in secondary wall polymer synthesis once full genomic data are available.
authors.affiliation: School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Millar
authors.forename: Julian P
authors.initials: JP
authors.lastname: Whitelegge
authors.forename: Laurence V
authors.initials: LV
authors.lastname: Bindschedler
authors.forename: Catherine
authors.initials: C
authors.lastname: Rayon
authors.forename: Alain-Michel
authors.initials: AM
authors.lastname: Boudet
authors.forename: Michel
authors.initials: M
authors.lastname: Rossignol
authors.forename: Gisèle
authors.initials: G
authors.lastname: Borderies
authors.forename: G Paul
authors.initials: GP
authors.lastname: Bolwell
mesh_terms: D002460:Cell Line; D002473:Cell Wall / Q000737:chemistry* / Q000378:metabolism; D013058:Mass Spectrometry; D008861:Microsomes / Q000737:chemistry / Q000378:metabolism; D010940:Plant Proteins / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D018547:Plant Stems / Q000737:chemistry* / Q000378:metabolism; D020543:Proteome / Q000032:analysis*; D014026:Nicotiana / Q000737:chemistry* / Q000201:enzymology / Q000378:metabolism; D052584:Xylem / Q000737:chemistry* / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D020543:Proteome