Establishment of regeneration and transformation system in Egyptian sesame (Sesamum indicum L.) cv Sohag 1.

Abstract

Sesame (Sesamum indicum L.) is an important oil crop in many tropical and sub-tropical regions of the world, yet has received little attention in applying modern biotechnology in its improvement due to regeneration and transformation difficulties. Here within, we report the successful production of transgenic fertile plants of sesame (cv Sohag 1), after screening several cultivars. Agrobacterium tumefaciens- carrying the pBI121 plasmid {neomycin phosphotransferase gene (NPTII) and a β-glucuronidase gene (GUS)} was used in all experiments. Recovery of transgenic sesame shoots was achieved using shoot induction medium (Murashige and Skoog MS basal salt mixture + Gamborg's B5 vitamins + 2.0 mg/l BA + 1.0 mg/l IAA + 5.0 mg/l AgNO3 + 30.0 g/l sucrose + 7.0 g/l agar + 200 mg/l cefotaxime and 25 mg/l kanamycin) and shoots were rooted on MS medium + B5 vitamins + 1.0 mg/l IAA + 10.0 g/l sucrose and 7.0 g/l agar. Rooted shoots were transplanted into soil and grown to maturity in greenhouse. Incorporation and expression of the GUS gene into T0 sesame plants was confirmed using polymerase chain reaction (PCR), reverse transcriptase-PCR (RT-PCR) and GUS histochemical assay. Several factors were found to be important for regeneration and transformation in sesame. The most effective were plant genotype and the addition of AgNO3 for successful recovery of sesame shoots. Co-cultivation time and optical density of the Agrobacterium were also critical for sesame transformation. This work is an attempt to open the door for further genetic improvement of sesame using important agronomic traits.