Electrophoretic and immunochemical techniques for the molecular reassessment of relationships within Vicieae

Abstract

In this study, an array of electrophoretic and immunochemical techniques was used to investigate the legumins, vicilins and albumins of seed storage proteins inPisum sativum,Vicia faba,Lens esculentum, andCicer arietinumto delimit the boundary of the tribeVicieaeand to clarify the systematic position of the genusCicer. The band patterns of the legumins of these species were broadly similar in that they had bands at Mr 60 kDa which disappeared in the presence of 2-mercaptoethanol, giving rise to two sets of new bands, at Mr approximately 40 kDa and 20 kDa, representing acidic or α and basic or β subunits. The band patterns of the vicilins were also quite similar in that they showed bands at Mr approximately 71 kDa (convicilin) and 50 kDa (vicilin), which were not altered by the presence of 2-mercaptoethanol. Serologically, the legumins ofVicia fabaandLens esculentumexhibited total identity withPisumlegumin antiserum under nonreducing conditions, whereas the legumin ofCicer arietinumexhibited only partial identity, which was attributed to the failure of the low molecular subunit pair (Mr 33 kDa) to react withPisumlegumin antiserum. On the other hand, the vicilins ofVicia faba,Lens esculentumandCicer arietinumhad only partial identity with the vicilin ofPisum sativum, which was due to the failure of a number of subunits along the electrophoretic patterns of these species to react withPisum sativumvicilin antiserum. The electrophoretic patterns ofVicia faba,Lens esculentumandCicer arietinumwere markedly different for the albumins. However, immunochemically they gave a positive reaction withPisummajor albumin antiserum (Mr 25 kDa) and showed a band with a molecular weight slightly higher than the major albumin ofPisum sativum. Extending the immunochemical study to members of thePhaseoleae, Glycineae, CajaneaeandDiocleaerevealed that the vicilin and legumin ofCicerwere more closely related to theVicieaethan to these tribes. Thus the data presented in this work recommended the classification ofCicerunderVicieaerather than as a separate tribeCicerideae.