2-DE polypeptide mapping of Posidonia oceanica Leaf, a molecular tool for marine environment analyses.

The aim of this research is to provide a molecular tool based on polypeptide mapping to investigate the flowering marine plant Posidonia oceanica. This plant is very vulnerable to contaminants; thus it is considered a valuable bio-indicator of water quality in bio-monitoring of coastal environments. Posidonia oceanica was found to be recalcitrant to the common protein extraction methods. In the present work, three different extraction procedures were compared to obtain high yield and quality protein extracts suitable for mono-dimensional and bi-dimensional electrophoresis (1-DE and 2-DE). Proteins were extracted from juvenile, intermediate and adult leaves in order to assess the influence of tissue differentiation on protein yield. The highest protein yield was obtained with 20% trichloroacetic acid (TCA) precipitation of proteins. The best extraction efficiency was found in juvenile leaves as compared with intermediate and adult ones. However, as a large amount of juvenile leaves is required for obtaining sufficiently large protein samples, these were considered not suitable for the electrophoretic analysis. Extensive sampling could introduce further damage in the meadows under study. High quality 2-DE polypeptide mappings were obtained only from intermediate and adult leaves; the good reproducibility of protein patterns indicates that this approach could be used to explore changes in protein expression of P. oceanica in response to altered environmental conditions. © 2008 Società Botanica Italiana.