Masters Degrees (Plant Sciences)
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Browsing Masters Degrees (Plant Sciences) by Author "Bezuidenhout, Mariëtte"
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Item Open Access Identification of a putative protein kinase gene involved in the resistant response of sunflower to rust(University of the Free State, 2004-09-04) Bezuidenhout, Mariëtte; Visser, B.; Van Der Westhuizen, A. J.English: Sunflower (Helianthus annuus) is a commercially important crop plant. Susceptible plants infected with leaf rust (Puccinia helianthi) leads to great yield losses. The aim of this study was to identify putative protein kinase genes from a resistant sunflower cultivar that are involved in the early resistance response when the plant is infected with leaf rust. Several differentially expressed cDNA fragments were isolated from infected resistant sunflower. One of these identified clones (D15) showed an 8.5 fold induction of gene expression 3 h.p.i. in infected resistant sunflower, while the expression in the susceptible infected cultivar was repressed. A second 31 fold activation was found 15 h.p.i. This second induction most probably forms part of induced SAR in the uninfected plant tissue. This cDNA clone showed homology to several protein kinase genes. In addition, the gene is present as a single copy within the genomes of susceptible and resistant sunflowers. A polymorphism in size was however evident between the genes present in the two cultivars. Three other cDNA clones were also selected on the basis of their expression profiles. These cDNAs showed homology to Apyrases, a Rac-protein and Xyloglucan endotransglycosylases respectively. The involvement of all four cDNAs in the activation of plant defense however still needs to be confirmed.