Submitted to: Plant Physiology Supplement
Publication Type: Abstract Only
Publication Acceptance Date: July 30, 1996
Publication Date: N/A
Technical Abstract: Many host response genes have been cloned from plants; some have been shown to enhance resistance when introduced into transformed plants. However, the generation of transgenic cereals to test the effectiveness of disease response genes is a lengthy and costly process. We have developed a rapid transient expression assay using barley coleoptiles for evaluating the ability of individual genes to confer disease resistance. Micro-particle bombardment is used to co-transform epidermal cells with a host response gene in combination with genes that regulate anthocyanin production. Transformed cells turn red in 1-2 days. Red cells are then inoculated with spores of the powdery mildew fungus, Erysiphe graminis f.sp. hordei. The effects of the transiently expressed host response gene on fungal development are observed microscopically on the living coleoptile tissues. The anthocyanins have no effect on development of the fungus. In initial experiments, host response genes for chitinase, Beta-1,3-glucanase, and a thaumatin-like protein each significantly reduced rates of infection by 1/2 to 2/3 in transiently expressing epidermal cells. Thus, the assay procedure provides a tool for prescreening host response genes singly or in combination for ability to confer disease resistance and is potentially useful for investigation of other genes postulated to have a role in host-parasite interaction.