Capillary electrophoresis of gliadins as a tool in the discrimination and characterization of hulled wheats (Triticum dicoccon Schrank and T. spelta L.)

Twenty-two lines of emmer (T. dicoccon Schrank) and 10 of spelt (T. spelta L.) were analyzed using capillary electrophoresis for their gliadins. These proteins were separated on an uncoated fused-silica capillary (30 cm long, 22 cm to detector, 50 micrometer i.d.) using the isoelectric buffer 40 mM aspartic acid, 4M urea, 0.5% (w/v) HEC, and 20% (v/v) acetonitrile. Samples were run for 20 min at 22kV and 42 degrees C. By using these conditions, gliadins were separated into 21-30 components (peaks and shoulders). The major peaks eluted between 4.5 and 8.5 min. Electrophoregrams of tested lines showed qualitative and quantitative differences, including number of peaks, presence or absence of some major peaks, and areas of peaks. Lines belonging to the same species can be discriminated mainly on the basis of beta- and omega-gliadin patterns. The gamma- and omega-gliadins seem to be more useful in the differentiation of emmer from spelt. The comparison of electrophoregrams relative to hulled and unhulled species evidenced the high similarity between species with the same genome composition (durum wheat-emmer, and common wheat-spelt).