title: A genetic survey of the pathogenic fungus Ophiostoma ulmi across a Dutch elm disease front in western Canada.
abstract: The natural population structure of the Dutch elm pathogen Ophiostoma ulmi was determined from isolated collected from across a Western Canadian disease front through an analysis of restriction-site polymorphisms in the ribosomal DNA repeat, length mutations in the mitochondrial genomes, and through DNA fingerprinting of the nuclear genomes using a minisatellite DNA probe. The 8.8-kbp rDNA repeat was selected from a genomic library, and restriction-site and genic maps were constructed for the nonaggressive and aggressive subgroups of O. ulmi. There were only three restriction-site differences that distinguished these two subgroups and no intrasubgroup variation was detected. All of the isolates collected from the disease front were of the aggressive subgroup and were represented by two distinct nuclear and four mitochondrial genotypes. The minority of the isolates were of a single genotype (type A nuclear DNA; type I mtDNA), indicating the presence of a single very large clone extending across much of Manitoba and into Saskatchewan.
authors.affiliation: Biology Department, University of Victoria, B.C., Canada.
authors.forename: W E
authors.initials: WE
authors.lastname: Hintz
authors.forename: R S
authors.initials: RS
authors.lastname: Jeng
authors.forename: D Q
authors.initials: DQ
authors.lastname: Yang
authors.forename: M M
authors.initials: MM
authors.lastname: Hubbes
authors.forename: P A
authors.initials: PA
authors.lastname: Horgen
mesh_terms: D001203:Ascomycota / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D001483:Base Sequence; D016172:DNA Fingerprinting; D004271:DNA, Fungal / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D014644:Genetic Variation; D008350:Manitoba; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000382:microbiology*; D010944:Plants / Q000382:microbiology*; D012150:Polymorphism, Restriction Fragment Length; D012091:Repetitive Sequences, Nucleic Acid; D012525:Saskatchewan; D014197:Trees / Q000382:microbiology
chemical_list: D004271:DNA, Fungal; D004272:DNA, Mitochondrial; D004275:DNA, Ribosomal