Reproducible Agrobacterium-mediated Transformation of Nigerian Cultivars of Tomato (Solanum lycopersicum L.)

This study was carried out to develop transformation protocol for the possible improvement of local cultivars of tomatoes in Nigeria using complete randomized design (CRD). The research was conducted at the Plant Biotechnology Centre, International Institute of Tropical Agriculture (IITA), Ibadan, Oyo State, Nigeria between May 2009 and December 2009. Seeds of three promising farmer preferred varieties of cultivars of tomatoes namely Ibadan local, Ife and JM94/46 were selected and cultivated in-vitro. Sterile cotyledon and leaf explants were transformed using Agrobacterium tumefaciens strain LBA4404 with plasmid (pOYE153). Transformed plants were analyzed using GUS assay and PCR methods. Results showed that leaf explants had higher transformation efficiency than cotyledon explants in the three cultivars. Ife cultivar had the best transformation efficiency in both explant types - leaf 42.5% and cotyledon 8.89%. Histochemical GUS assay of transgenic plants showed blue coloration in leaves, stems and roots. PCR analysis showed amplification of 600 bp fragments of GUS and nptII genes in the transgenic plants on 1.0% agarose gel. The GUS and nptII genes were successfully integrated into the three cultivars of tomatoes thereby providing a reliable transformation protocol for the genetic improvement of local cultivars of tomatoes for desirable traits such as longer shelf-life, pest and disease resistance, enhanced nutrients, higher soluble solids, etc