Electrophoretic Characterization of Water Soluble Seed Proteins and the Relationship between Some Legume Species in Nigeria

摘要

Legume seeds are a rich source of dietary proteins consumed by humans and livestock. In this research, a total of six species of grain legumes viz., Vigna unguiculata sub- specie unguiculata (black-eyed bean), Vigna unguiculata (patisco), Vigna unguiculata unguiculata sub- specie sesquipedalis (yardlong bean), Phaseolus vulgaris (red kidney bean), Cajanus cajan (pigeon pea) and Mucuna pruriens (velvet or devil bean) consumed in eastern Nigeria were studied to assess their genetic variability and relationship. These grains were characterized by the numerical analysis of seed protein profiles obtained by using native - and SDS- PAGE techniques. The average polymorphisms of these species were 0.00% in Native-PAGE (beta-mecarptoethanol absence) and SDS-PAGE (beta-mecarptoethanol presence), 10.71 % in SDS-PAGE (beta-mecarptoethanol absence) and 57.769% in Native-PAGE (beta-mecarptoethanol presence). V. unguiculata unguiculata sub- specie sesquipedalis and P. vulgaris showed the highest similarity index(94.12%) while M. pruriens and the two species V. unguiculata unguiculata sub- specie unguiculata and V. unguiculata showed the lowest (22.2%) in Native-PAGE. Also, V. unguiculata unguiculata and V. unguiculata unguiculata sub- specie sesquipedalis showed the highest similarity index (72.72%) while P. vulgaris and C. cajan showed the lowest (0.00%) in SDS-PAGE. Cluster analysis showed that water soluble proteins in V. unguiculata unguiculata sub- specie unguiculata and C. cajan; V. unguiculata unguiculata sub- specie sesquipedalis and M. pruriens are closely related to each other. The grains contained proteins with molecular weights in the range of 20-28 kDa. This study indicated that the numerical analysis of seed protein profiles offer no concrete answer to the identity of the bean species studied, however, the method provided extra banding pattern for the discrimination of these bean species consumed in Nigeria.