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Chloroplast transformation vectors require an expression cassette flanked by homologous plastid sequences to drive plastome recombination. The 16-23 plastome region was selected and using this region, a new species-specific plastid transformation vector CuIA was developed with pKSII as a backbone by inserting the 16- and -23 sequences from L. An independent expression cassette with gene encoding aminoglycoside 3'-adenylyltransferase with controlling elements is added into the- intergenic region that confers resistance to spectinomycin. An efficient plastid transformation in bitter melon ( L.) was achieved by bombardment of petiole segments. The frequency of transplastomic plants yielded using standardized biolistic parameters with CuIA vector was two per 15 bombarded plates, each containing 20 petiole explants. Integration of gene was verified by PCR analysis in transplastomes. Transplastomic technology developed may be a novel approach for high level expression of pharmaceutical traits.

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In the present investigation we report stable plastid transformation in L., a versatile medicinal herb via particle gun method. The vector KNTc, harbouring as a selectable marker and as a reporter gene which were under the control of synthetic promoter pNG1014a, targets inverted repeats,/ of the plastid genome. By use of this heterologous vector, recovery of transplastomic lines with suitable selection protocol have been successfully established with overall efficiency of two transgenic lines for 25 bombarded leaf explants. PCR and Southern blot analysis demonstrated stable integration of foreign gene into the target sequences. The results represent a significant advancement of the plastid transformation technology in medicinal plants, which relevantly implements a change over in enhancing and regulating of certain metabolic pathways.

Here, we report for the first time, the optimized conditions for microprojectile bombardment-mediated genetic transformation in Vassourinha (Scoparia dulcis L.), a Plantaginaceae medicinal plant species. Transformation was achieved by bombardment of axenic leaf segments with Binary vector pBI121 harbouring β-glucuronidase gene (GUS) as a reporter and neomycin phosphotransferase II gene (npt II) as a selectable marker. The influence of physical parameters viz., acceleration pressure, flight distance, gap width & macroprojectile travel distance of particle gun on frequency of transient GUS and stable (survival of putative transformants) expressions have been investigated. Biolistic delivery of the pBI121 yielded the best (80.0 %) transient expression of GUS gene bombarded at a flight distance of 6 cm and rupture disc pressure/acceleration pressure of 650 psi. Highest stable expression of 52.0 % was noticed in putative transformants on RMBI-K medium. Integration of GUS and npt II genes in the nuclear genome was confirmed through primer specific PCR. DNA blot analysis showed more than one transgene copy in the transformed plantlet genomes. The present study may be used for metabolic engineering and production of biopharmaceuticals by transplastomic technology in this valuable medicinal plant.