Current status of transformation in bread and durum wheats and modifications of gluten quality

The current status of wheat transformation is reviewed in this paper, with the emphasis on biolistic-mediated DNA delivery. The conditions for target explant culture and transformation have been optimised and successfully adapted to a wide range of wheat genotypes, including models and a number of elite varieties. The robust wheat transformation systems developed have now been applied to manipulate the amount and composition of the hmw glutenin subunits which are the major determinants of wheat dough elasticity. SDS-PAGE analysis of seed proteins has indicated that the novel protein bands are expressed in transgenic plants. A 2g Mixograph has been used to analyse the functional properties of additional HMW subunits lAxl and 1Dx5, the results showing that the mixing time and peak resistance are increased, indicating increased dough strength of bread and durum wheats. The alteration of dough strength demonstrates the great potential for wheat quality improvement by genetic modification technologies. Transgenic lines of genetically modified bread and pasta wheats are now being analysed in the field. The stability and heritability of transgenes, both markers (uidA, bar and neo) and genes of interest (lAxl, 1Dx5), integrated into transgenic bread and durum wheat genomes have been studied and typical Mendelian transmission patterns have been observed in the progenies of T₁ T₂ and T₃ generations of transgenic lines.