Particle bombardment-mediated co-transformation of the gene in wheat and the associated changes in defense mechanisms in transgenic plants infected with .

is a major global pathogen of cereals and is considered the main causal agent of head blight disease in wheat. Infection with causes a significant reduction in crop yield and quality; therefore, it is very important to improve wheat pathogen resistance. In the present study, the plasmid pAHCht-2 harboring the () gene for pathogen resistance and the plasmid pAB6 containing the reporter and selectable marker genes were used for genetic transformation of immature embryo-derived calli of the Egyptian wheat cultivar Giza 164 using particle bombardment. Associated changes in defense mechanisms in the transgenic plants were investigated. The transgenic plants had significantly decreased total protein content, phenolic compounds and antioxidant enzyme activities (peroxidase and catalase), and significantly increased phenylalanine ammonia lyase and chitinase activities compared with non-transgenic plants under biotic stress conditions caused by infection. Our results show that activating a specific program of gene expression related to environmental stress conditions can reduce the cost of the stress on plant metabolism.