title: Suppression of polygalacturonase gene expression in the phytopathogenic fungus Ophiostoma novo-ulmi by RNA interference.
abstract: The fungal pathogen, Ophiostomo novo-ulmi, has been responsible for the rapid decline of American elm (Ulmus americana) across North America and remains a serious threat to surviving elm populations. The production of pectinolytic polygalacturonase enzymes has been implicated as a virulence factor for many fungal pathogens, including O. novo-ulmi. Previous work has shown that the targeted disruption of the endopolygalacturonase gene locus epg1 of O. novo-ulmi reduced, but did not eliminate pectinase activity. In the present study, we evaluated the use of RNA interference (RNAi) as a method of suppressing expression of the epg1 locus in O. novo-ulmi and compared its efficiency to the gene disruption method. While there was a reduction in epg1-specific mRNA transcripts and in the amount of polygalacturonase enzyme secreted for both methods of gene regulation, neither method completely suppressed the expression of pectinase activity. There was, however, a significantly greater reduction in both transcript levels and secreted enzyme observed for some of the RNAi transformants. As the first demonstration of RNAi in O. novo-ulmi, this method of gene regulation shows promise in future studies of gene expression and pathogenicity.
authors.affiliation: Biology Department, Centre for Forest Biology, University of Victoria, PO Box 3020, STN CSC, Victoria, BC, Canada V8W 3N5.
authors.forename: Joyce S
authors.initials: JS
authors.lastname: Carneiro
authors.forename: Paul Y
authors.initials: PY
authors.lastname: de la Bastide
authors.forename: Meghan
authors.initials: M
authors.lastname: Chabot
authors.forename: Lindsey
authors.initials: L
authors.lastname: Lerch
authors.forename: William E
authors.initials: WE
authors.lastname: Hintz
mesh_terms: D015536:Down-Regulation; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D055156:Ophiostoma / Q000201:enzymology / Q000235:genetics*; D010935:Plant Diseases / Q000382:microbiology*; D011096:Polygalacturonase / Q000235:genetics* / Q000378:metabolism; D034622:RNA Interference; D034403:Ulmus / Q000382:microbiology*
chemical_list: D005656:Fungal Proteins; D011096:Polygalacturonase