ENHANCEMENT OF WHEAT (Triticum aestivum L.) TOLERANCE TO ENVIRONMENTAL STRESS BY GENETIC ENGINEERING

Abstract

This study aimed to improve drought tolerance of Egyptian wheat cultivar Giza 164 by transforming it with the chimeric fructan­ accumulating gene (cpylsacZJ). Plant transformation was done in the immature embryo-derived calli using the biolistic bombardment. Tissue culture and transformation protocols were performed using bar gene as a selectable marker against the herbicide bialaphos. One putative transgenic plant was successfully detected by leaf painting with the herbicide. Molecular analyses were done on the structural and functional levels for both genes. PCR and Southern blotting indicated the presence and integration of both genes in the genomic background of T0 plant. PCR was then done to ensure the inheritance of genes of interest. At the functional level, RT-PCR confirmed the expression of bar as well as sacB gene. Drought stress experiment was conducted in the greenhouse on T1 plants to evaluate ten yield-related traits. The statistical analysis indicated that the transgenic T1 plants had better overall performance under control and treatment. In conclusion, the results revealed that the expression of fructan-accumulating gene into wheat conferred tolerance to drought stress.

Key words: Triticum aestivum, immature embryos, transformation, biolistic bombardment, drought tolerance, fructan, leaf-painting, bialaphos, PCR, genomic Southern, RT-PCR.