The proteome of maritime pine wood forming tissue

Wood is one of our most important natural resources. Surprisingly, we know hardly anything about the details of the process of wood formation. The aim of this work was to describe the main proteins expressed in wood forming tissue of a conifer species (Pinus pinaster Ait.). Using high resolution 2-DE with linear pH gradient ranging from 4 to 7, a total of 1039 spots were detected. Out of the 240 spots analyzed by MS/MS, 67.9% were identified, 16.7% presented no homology in the databases, and 15.4% corresponded to protein mixtures. Out of the 57 spots analyzed by MALDI-MS, only 15.8% were identified. Most of the 175 identified proteins play a role in either defense (19.4%), carbohydrates (16.6%) and amino acid (14.9%) metabolisms, genes and proteins expression (13.1%), cytoskeleton (8%), cell wall biosynthesis (5.7%), secondary (5.1%) and primary (4%) metabolisms. A summary of the identified proteins, their putative functions, and behavior in different types of wood are presented. This information was introduced into the PROTICdb database and is accessible at http://cbib1.cbib.u-bordeaux2.fr/Protic/Protic/home/index.php. Finally, the average protein amount was compared with their respective transcript abundance as quantified through EST counting in a cDNA-library constructed with mRNA extracted from wood forming tissue.