title: A nine-year genetic survey of the causal agent of Dutch elm disease, Ophiostoma novo-ulmi in Winnipeg, Canada.
abstract: The causal agent of Dutch elm disease, Ophiostoma ulmi s. lat., has been spreading across North America since the 1920s. The population of the pathogen in Winnipeg, Manitoba, Canada was surveyed in 1993 and 2002 using a combination of RAPD marker analysis, vegetative compatibility tests, and surveys for viral double-stranded RNA (dsRNA). The data presented here show that the population, based on the vegetative compatibility and RAPD analysis, was highly genetically uniform, and has remained so for the nine-year duration of the study. The pathogen population was also monitored for the presence and spread of dsRNA molecules that, depending on identity, can be associated with a diseased phenotype and reduction of virulence in the pathogen. The current study found a very low incidence of dsRNA, and did not find any evidence for spread of these molecules through the population, even though there appeared to be no barriers to the transfer of the dsRNA between Winnipeg isolates. Despite the observation that isolates infected with the Winnipeg dsRNA showed no obvious phenotypic differences, the low incidence of dsRNA in general suggests that infected isolates do not compete as successfully as the uninfected isolates. The highly clonal nature of the pathogen population may be exploited in a control strategy.
authors.affiliation: Biology Department, University of Victoria, P.O. Box 3020 STN CSC, Victoria, BC, V8W 3N5, Canada.
authors.forename: Brad
authors.initials: B
authors.lastname: Temple
authors.forename: Philip A
authors.initials: PA
authors.lastname: Pines
authors.forename: William E
authors.initials: WE
authors.lastname: Hintz
mesh_terms: D001203:Ascomycota / Q000235:genetics*; D010935:Plant Diseases / Q000382:microbiology*; D012331:RNA, Fungal / Q000032:analysis; D019105:Random Amplified Polymorphic DNA Technique; D034403:Ulmus / Q000382:microbiology*
chemical_list: D012331:RNA, Fungal