Separation and characterization of needle and xylem maritime pine proteins

Two-dimensional gel electrophoresis (2-DE) and image analysis are currently used for proteome analysis in maritime pine (Pinus pinaster Ait.). This st udy presents a database of expressed proteins extracted from needles and xy lem, two important tissues for growth and wood formation. Electrophoresis w as carried out by isoelectric focusing (IEF) in the first dimension and sod ium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in the se cond. Silver staining made it possible to detect an average of 900 and 600 spots on 2-DE gels from needles and xylem, respectively. A total of 28 xyle m and 35 needle proteins were characterized by internal peptide microsequen cing. Out of these 63 proteins, 57 (90%) could be identified based on amino acid similarity with known proteins, of which 24 (42%) have already been d escribed in conifers. Overall comparison of both tissues indicated that 29% and 36% of the spots were specific to xylem and needles, respectively, whi le the other spots were of identical molecular weight and isoelectric point . The homology of spot location in 2-DE patterns was further validated by s equence analysis of proteins present in both tissues. A proteomic database of maritime pine is accessible on the internet (http://www.pierroton. inra. fr/genetics/2D/).