Comparative in vitro regeneration and transient transformation efficiency of different genotypes of wheat (Triticum aestivum)

Genetic engineering has emerged as an important method for genetic improvement of crop plants including wheat (Triticum aestivum L.). Hence, there is a need to establish an efficient transformation and regeneration protocol for high-throughput gene function validation and development of transgenic wheat cultivars. In the present study, in vitro response of 30 different Indian wheat genotypes has been analyzed to select the best genotype for callus induction and plantlet regeneration. Of the 30 genotypes screened, most showed high callusing efficiency ranging from 80 to 100%. Shoot regeneration was maximum (97.7%) in the genotype HD 2888 followed by K 9533 (84.4%). All the 30 genotypes were further analyzed for genetic transformation efficiency by bombarding the mature embryo-derived calli with the plasmid pDM 803, containing GUS gene driven by the rice actin 1 promoter. Transient transformation frequency was calculated based on the appearance of GUS positive spots on the bombarded calli. The transformation efficiency ranged from 0.29 in the genotype HI 1418 to the highest of 46.9% in HD 2894. The present study revealed a wide variation in in vitro regeneration and transformation efficiency of wheat genotypes. The developed protocol could be employed for genetic transformation and functional genomics studies in wheat.