Variation of the legumin seed storage protein amongst Vicia species

Abstract

Variation in legumin, the major seed storage protein of Vicia faba was investigated in different (primitive and cultivated) varieties of V. faba and in other primitive Vicia species. Qualitative variation in legumin subunit patterns on gel electrophoresis was less within the species V. faba than the variation between Vicia species. However, the large seeded modern V. faba cultivars showed much increased levels of the ‘main’ legumin subunit pairs. Analyses of amino acid composition, and nitrogen and sulphur content did not show systematic variation between the samples tested, and suggested that breeding and selection had not decreased protein content or nutritional quality. It was concluded that the heterogeneities of legumin genes in the Vicia species examined are comparable, and that selection for a large-seeded phenotype in V. faba has had the effect of increasing the expression of a subset of legumin genes, those encoding the ‘main’ subunit pairs.