TRANSFORMATION SYSTEM OF MATURE EMBRYO OF SOME EGYPTIAN BARLEY GENOTYPES

Transformation of barley based on the infection of mature embryos with Ag- robacterium tumefactions system used for transformation of explants El- Kasrgenotype using the strain harbors the pITB-AFP plasmid vector which contains defensin (AFP) gene, hygromycin phos- phor transferase (hpt) and β-glucuronidase (GUS) genes as selectable and marker genes. The Transient expression of AFP gene was investigated as a preliminary test of the transformation efficiency. Trans- formation experiments were carried out with different parameters and the one bar- ley genotype El-Kasr. The tested trans- formation parameters included: the type of explants mature embryos based on the results of GUS transient expression. PCR analysis using primers specific for the AFP and GUS genes with specific probe was applied.

The results revealed that mature embryo axis explants infected with Agro- bacterium showed blue spot (positive Gus expression). Conversely, negative GUS expression was observed with untrans- formed embryo axis of barley mature -

embryos (intact) of the three genotypes gave the highest percentages of embryo-genic calli when cultured on medium M1 in comparison with the other two  media. This was followed by the percentage of roots of the two genotypes (Giza126 and Giza130), respectively, (9% and 0.1%). PCR showed bands corresponding to the expected size of 300 bp for partial length of the AFP gene, and the expected size of 300 bp for partial length of GUS gene by intact mature embryos of genotype (El- Kasr) on the three media (16%). This was followed by the percentage of roots of the two genotypes (Giza126 and Giza130), respectively. Evidently, El-Kasr is the best genotype for callus, shoots and roots that were amenable totransformation.