An improved protocol for rapid and efficient Agrobacterium mediated transformation of tomato (Solanum lycopersicum L.)

Abstract: Transformation of tomato with heterologous genes requires rapid and efficient transformation protocols. Agrobacterium mediated transformation protocol of tomato (Solanum lycopersicum L.) cv. 'Arka Vikas' using dreb1A gene under Rd29A promoter in pCAMBIA 2301 binary vector was optimized by varying parameters such as type of explant, type and concentrations of hormones. Hypocotyls were found to be the best explants for shoot regeneration in tomato compared to cotyledons with 53.2 and 22.8% shoot regeneration, respectively. In the shoot regeneration medium, 0.1 mgL⁴ IBA as a source of auxin gave nearly 50% higher shoot regeneration than IAA at similar concentration. With this protocol it was possible to obtain transformed plants within a period of 77 days with a high regeneration and transformation efficiency (34%) compared to over 120 days using earlier published protocols. The T₁ generation plants segregated in a 3:1 ratio for the transgene and Southern blot analysis of the selected plants had shown the transgene integration was at a single locus. With this method it is possible to rapidly and efficiently generate transgenic tomato plants.