BIOTECHNILOGIES USED IN GENETIC TRANSFORMATION OF TRITICUM AESTIVUM

: A mini overview

Abstract

Wheat improvement through genetic transformation has huge potential to meet its ever growing demand. Various methods have been devised and used to achieve this goal. The list includes methods like electroporation, micro-injection, liposome-mediated, biolistic and the Agrobacterium tumefaciens-mediated transformation method. Electroporation is effective method of DNA delivery into the target cells however it can be applied to protoplasts only. This has been main disadvantage as protoplast cultures for most of the cereals are strongly genotype dependent and difficult to obtain. Microinjection method, to some extent, is considered targeted gene delivery method. Its use has been limited, so far, for cereal transformation. Moreover it demands highly skilled personals and sophisticated technology. Stable transgene integration has been reported with liposome mediated gene transfer method. Like electroporation, this technique also relies on protoplasts culture which has been its obvious limitation. Genetically modified plants have been developed through particle bombardment method. It has been second most popular method adopted for wheat improvement. However this technique leads to integration of multiple copies of transgene at single locus that ultimately results in gene silencing. Agrobacterium tumefaciens-mediated transformation method is most famous method and frequently used for developing transgenic plants, mainly due to its advantages like simple integration pattern, being less laborious, and cost effective. In recent years significant progress has been made to successfully employ this method for transformation of monocotyledonous plants. However, in the case of wheat, involvement of tissue culture has been main hurdle so far, which is mainly because of recalcitrant nature of wheat. In past few years, improved methods have been developed that bypass in vitro culturing during transformation method