Genetic Engineering of Wheat and Barley

Abstract

We have obtained stably transformed cell lines of wheat and barley by biolistics-mediated delivery of an improved plasmid pRC62 (ACT-1D-GUS::NPTII-NOS) into the non-embryogenic cell cultures. Enzyme assays and Southern hybridization confirmed functional expression and stable integration of the chimeric genes into the wheat and barley genomes. These results demonstrated that efficient delivery and stable expression of foreign genes into wheat and barley cells was no longer a constraint for accomplishing genetic engineering of these crops. However, the major problem which remained was the lack of an efficient system for regeneration of fertile plants from transformed cells. We have now resolved this problem by developing a system for enhanced somatic embryogenesis and plant regeneration from isolated scutellar tissue of wheat and barley. This scutellar-based regeneration system has been successfully used for developing a simple and reproducible protocol for the production of self-fertile transgenic wheat plants. Using this protocol, transgenic wheat plants carrying the bar, gus and npt genes have been produced. Molecular and biochemical analyses confirmed stable integration and functional expression of transgenes in R0 and R1 transgenic plants. Mendelian inheritance of bar gene was observed in R1 and R2 progeny. The protocol is being optimized for production of transgenic barley plants. Since the protocol avoids the need for establishing long-term callus, cell suspension or protoplast regeneration procedures, it has the potential for becoming a practical system for gene transfer in wheat and barley. The procedure will facilitate manipulation of various agronomic and quality traits by direct gene transfer into these major cereal grain crops.