PROTEIN VARIABILITY IN CEREAL CYST NEMATODES FROM DIFFERENT GEOGRAPHIC REGIONS ASSESSED BY 2-DIMENSIONAL GEL-ELECTROPHORESIS

The protein variability of twelve populations of cereal cyst nematodes , originating from seven countries (four continents), was studied on t hree samples of white females per population, reared in controlled con ditions on the same wheat, Triticum aestivum cv. Arminda. The pathogen ic characteristics of each isolate were obtained from the literature a nd/or complementary host tests. Three electrophoreses were run for eac h protein sample with light modifications in migration (O'Farrell, 197 5) and staining (Oakley et al., 1980) techniques. 320 polypeptide spot s were identified on all the populations tested. The protein patterns were compared by an image computing analysis with a Var station (4000. 60), a scanner (Eikonix, Kodak), and a Kepler software combination. Di fferent levels of protein acceptance were applied, based on their volu me and/or amplitude range. The similarity indices (F) and genetic dist ances (D = 1-F) were calculated from identical spots. Dendrograms were built following the UPGMA method. Although some variability was obser ved between populations, clear genetic dissimilarities separate H. ave nae sensu stricto from Gotland strain isolates. In the H. avenae sensu stricto group, two French populations and one isolate from South Aust ralia were very similar. Specific proteins common to both French Ha12 and Ha12/Fr2 pathotypes were characterized. The use of image computing analysis to compare protein patterns is discussed.