SDS-PAGE Characterization of Three Elite Solanum lycopersicum (L.) Varieties

Abstract

Aims: The overall objective of this research work was to characterize and compare the leaf and seed storage protein profiles of three elite Solanum lycopersicum (L.) varieties, which are Roma VF, Tropimech, and UC82B, in order to assess their biochemical diversity and genetic relatedness, which can be explored in breeding and improvement of tomatoes. Study Design: The experiment was laid out in a Randomized Complete Block Design (RCBD) with five replications. Place and Duration of Study: The study was carried out in the screen house and laboratory facilities of the Department of Botany, Obafemi Awolowo University, Ile-Ife, Nigeria, during the 2021 growing season. Methodology: Three elite Solanum lycopersicum (L.) varieties, i.e., Roma VF, Tropimech, and UC82B, were cultivated in a Randomized Complete Block Design with five replications. At maturity, leaves and seed samples were collected, processed, and used for protein extraction. The storage proteins were separated by Sodium Dodecyl Sulphate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) on a 12% resolving gel at the Biotechnology Laboratory, Department of Animal Science, Obafemi Awolowo University,Ile-Ife, Nigeria. Protein banding patterns were analyzed for genetic relatedness and diversity. Results: The SDS-PAGE analysis revealed the predominance of fast bands in the protein profile of the leaf (61.76 %) and the seed (74.36%), signifying the high molecular weights of the protein bands. It also revealed the presence of generic bands at 0.6 cm - 1.0 cm, 5.2 cm, and 5.8 cm - 6.5 cm. for the leave and 4.2 cm - 4.5 cm, 4.5 cm - 4.9 cm, 5.2 cm - 5.4 cm, 5.8 cm - 6.0 cm, 6.2 cm - 6.3 cm, 6.3 cm - 6.5 cm for the seed protein indicating their common ancestry, and supporting their taxonomic grouping as members of same taxon. Unique bands were identified in the leaves (4.8 cm - 5.1 cm for Roma-VF, 3.3 cm and 4.4 cm for Tropimech; 1.0 cm, 4.1 cm, 4.2 cm, 4.4 cm, 4.6 cm, 5.4 cm and 5.6 cm for UC82B), and seeds (0.6 cm - 0.8 cm, 1.3 cm - 1.6 cm, 2.7 cm, and 4.7 cm - 4.9 cm for Roma-VF; 2.1 cm, 2.5 cm, and 3.0 cm for Tropimech; 2.2 cm for UC82B) which serve as distinctive biochemical fingerprints for each variety, and are useful for cultivar identification and purity testing of the varieties. Conclusion: The variations in the leaf and seed proteins identified in this study confirm the existence of genetic diversity among the elite tomato varieties, which could serve as valuable biochemical markers for the identification and selection of the different varieties. These results, therefore, validate the use of SDS-PAGE as a useful tool in tomato breeding programs for improving nutritional and genetic quality.