Crude Protein Profiling of Varieties of Capsicum annuum and Capsicum frutescens using SDS-PAGE.

Abstract

The study was aimed at assessing the genetic variation and relatedness among four Capsicum varieties through electrophoretic separation of their leaf and seed proteins by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Total seed and leaf proteins were extracted and separated on 12% polyacrylamide gels using standard protocols. Distinct polymorphism in electrophoretic banding patterns of seed and leaf proteins was observed in the four Capsicum varieties through a total of thirty-eight (38) polypeptide bands in the seeds and a total of seventeen (17) polypeptide bands in the leaves analyzed. Variation existed not only in the number of bands but also in the intensity of bands in both the leaf and seed samples studied. Sokal and Sneath's coefficient of similarity revealed a generally high level of similarity in the seed protein bands of the four varieties studied ranging from 50% to 100%. It also revealed an average level of similarity in the leaf protein bands of the four varieties of Capsicum studied ranging from 16.7% to 83.3%. A dendrogram constructed based on the Single Linkage Cluster Analysis(SCLA) using the relative mobility values of seed and leaf proteins of the four varieties revealed two major clusters. From the seed, cluster 1 contains (C. annuum var. abbreviatum and C. annuum var. acuminatum), and cluster 2(C. annuum var. grossum, and C.frutescens var.baccatum). Also, two prominent clusters were revealed in the leaf sample, with cluster 1 containing (C. annuum var. abbreviatum, C. annuum var. acuminatum and C.frutescens var.baccatum) and cluster 2(C. annuum var. grossum). Significance of the findings has been discussed. Plant breeders can use the information on variation and relatedness among the Capsicum species for cultivar development in pepper.