Comparative proteomic analysis of Orobanche and Phelipanche species inferred from seed proteins

Orobanche and Phelipanche species are root parasitic plants some of which infect important crops, causing extensive damage. In an attempt to unravel molecular systematic in these genera using protein markers, we established the protein profile of twelve species by two-dimensional gel electrophoresis (2-DE). Proteins were detected by Sypro Ruby staining and the gel images were digitalised and analysed. The 2-DE maps contained from 30 to 140 protein spots for the analysed species. A virtual master gel was built with spots present in all species and revealing the presence of 260 protein spots. Only one protein was monomorphic, while 143 were unique to a single species. Proteins were scored for the presence or absence of homologous spots to create a binary matrix. Phylogenetic analysis was carried out using maximum parsimony and distance method. The trees obtained were rooted using Cistanche phelypaea as an out-group. Both analyses showed Orobanche as a monophyletic group. AMOVA analysis revealed phenotypic diversity between species within genera, as well as a considerable level of variation between genera. This is a first step to help in the phylogenetic classification of parasitic plants by means of proteomics.