Protein variability among Portuguese and other populations of Globodera rostochiensis revealed by two-dimensional gel electrophoresis with computed image analysis

Silver-stained two dimensional gel electrophoresis (2-DGE) was used to char acterize 46 populations of G. rostochiensis and, as an outgroup, one popula tion of G. pallida. Protein patterns of white females were compared with th e aid of computer assisted image analysis using Kepler software. A syntheti c master pattern of G. rostochiensis, built with spots present in all popul ations and detected in at least two of three gels of each population, revea led the presence of 379 protein spots. The populations were compared taking into account the main spots present in each isolate (spots present in two of three gels, amplitude greater than 7, volume greater than 500 and with v alues fitting the Gaussian model). Comparison allowed the identification of 200 polymorphic spots. Similarity indices (F) and genetic distances (D = 1 - F) between populations were calculated on the basis of homologous polymo rphic spots, and a dendrogram was constructed according to the UPGMA method . Bootstrap analysis was used to assess the significance of the results fro m the phenetic study. The presence or absence of specific spots in some G. rostochiensis populations is discussed. Further biochemical and biological studies are necessary to determine if specific proteins are Linked to virul ence.