Genetic transformation of watermelon (Citrallous lanatus) by electroporation

Abstract

Experiment was conducted at IIHR, Bangalore to optimize the parameters for watermelon transformation using the Gus reporter gene by electroporation. The gene transfer was done in vitro using seed-derived embryos and in vivo using nodal meristem of watermelon variety Arka Manik. The uptake and expression of the said gene in the embryos was confirmed by histochemical staining with X-glue showing blue coloured cells. Further, the higher gus activity was observed by a higher staining pattern and intensity in the embryos electroporated with plasmid PB 1121 as compared to the plasmid P353G4INT. Higher Gus expression with both the plasmid was observed by using ten pulses from an experimental decay pulse of 400V over duration of 99 MSEC as compared with 5 pulses. Higher transformation frequencies (48.83%) were achieved by electroporation of watermelon nodal buds in vivo using dot blot analysis of R1 plants. Southern transfer and hybridization of the restriction digested R1 genomic DNA samples confirmed the stable integration of the gene/DNA fragments in the watermelon genome.