Submitted to: Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/3/2006
Publication Date: 3/31/2006
Citation: Malkus, A., Chung, K., Chang, C., Ueng, P.P. 2006. Characterization of the tri-functional histidine biosynthesis gene (his) in wheat stagonospora leaf blotch pathogen, phaeosphaeria nodorum. Plant Pathology. 15:55-62 Interpretive Summary: Septoria disease is responsible for important economic losses in the production of cereal crops. The disease is caused by a complex of several different species of fungus that are difficult to distinguish from one another, hindering efforts to devise measures for fungus-specific disease management. In this work, we isolated and characterized a gene that is involved in the synthesis of histidine, an essential amino acid, by the Septoria disease fungi. Our data indicated that the gene, and the protein that it codes for, can be used as a tool to differentiate Septoria disease fungi and to gain new understanding about the evolution of the fungi. The results will be of interest to scientists and diagnostics laboratories.
Technical Abstract: The histidine biosynthesis gene (his) sequence was obtained from wheat-biotype Phaeosphaeria nodorum genomic DNA using a “step down” PCR amplification technique. The 2700-bp his gene fragment contained two exons and a 51-bp intron. The two exons of this gene encoded a complete 881-amino acid protein. Like the histidine synthesis proteins in other filamentous ascomycetes, the deduced protein contained the conserved domains for three biosynthetic activities: phosphoribosyl-AMP cyclohydrolase (PRA-CH; EC 22.214.171.124), phosphoribosyl-ATP pyrophosphohydrolase (PRA-PH; CE 126.96.36.199), and histidinol dehydrogenase (HDH; EC 188.8.131.52). The substrate and zinc ion binding location in this tri-functional histidine biosynthesis protein is discussed.