In vitro plantlet regeneration and Agrobacterium-mediated genetic transformation of wheat (Triticum aestivum L.)

摘要

Different explants such as mature and immature embryos, seeds, endosperms, leaves, shoot bases and root tips of four local wheat (Triticum aestivum L.) varieties, namely Sourav, Gourav, Kanchan and Protiva were evaluated for their in vitro callus induction and regeneration of plantlets as well as Agrobacterium-mediated genetic transformation. Among the explants immature embryo was found to be the best for callus induction and shoot regeneration. Profuse callus developed when MS was supplemented with 5.5 mg/l 2,4-D. Maximum shoot regeneration was obtained on MS medium containing 0.5 mg/l BAP, 0.5 mg/l Kn and 25 mg/l tyrosine. Majority of regenerated shoots (90 percent) developed roots on half strength of MS without any hormonal supplement. Plantlets were successfully established in soil. No remarkable variation was observed among the wheat varieties regarding their ability for callus induction and shoot regeneration. Two strains of Agrobacterium, namely LBA4404 containing pBI121 and EHA105 havingplasmid pCAMBIA1301 were used in transformation experiments. Among the two strains EHA105 was found to be compatible to the aforesaid four local varieties of wheat. Maximum transformation efficiency, monitored by transient GUS histochemical assay, was obtained in callus derived from immature embryos with a bacterial suspension of optical density 0.75 at 600 nm.