QUANTITATIVE ANALYSIS OF PROTEIN AMOUNT IN MARITIME PINE

¹ IBET–Grupo Pinus (6.06), Apartado 12, P-2781-901, Portugal

² INRA-Equipe de Genetique et Amelioration des Arbres Forestiers, BP45, F-33610 Cestas - France

In the past few years, large amount of data has accumulated based on two-dimensional electrophoresis (2-DE) protein patterns on maritime pine. Two main data sets were obtained: (i) from xylem tissues associated with various type of wood (normal and reaction wood), and (ii) from needles of well watered and drought stressed seedlings. Computer-assisted analysis of 2-DE gels allowed the quantification of a large number of protein spots (135 and 163 in xylem and needles, respectively) in a large number of samples. Furthermore, 50 spots were characterised by internal amino acid sequencing or electrospray ionization MS/MS. Ninety percent of them were identified. Informations about the wood characteristics (mechanical and chemical) and the plant water status were also made available for each xylem and needle samples, respectively. The availability of protein amount, phenotypic data and protein function allowed the development of “functional proteomics”. In the two above referred experiments, clustered-correlation analysis allowed the classification of proteins according to their expression profiles, revealing gene products which can be under the same control mechanism. Based on known function proteins, we identified biologically-meaningful clusters such as : (i) proteins corresponding to specific gene products (gene family), (ii) proteins characterised by a similar function (same metabolic pathway), and (iii) proteins located in the same cellular compartment. The possibility of obtaining regulatory correlations and anticorrelations between proteins will provide us with a new category of homology (“regulatory homology”) in tracing functional relationships and possibly to infer protein function of unknown proteins and to identify partner proteins.