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Molecular Plant Pathology

Mitochondrial DNA of Puccinia graminis f. sp. avenae: Molecular Cloning, Restriction Map, and Copy Number. J. Sock, Gesamthochschule Kassel, FB 20, Nordbahnhofstr. la, 3430 Witzenhausen, Germany; R. Rohringer(2), and J. A. Kolmer(3). (2)Institut für Pflanzenpathologie und Pflanzenschutz, Universität Göttingen, Grisebachstr. 6, 3400 Göttingen, Germany; (3)Agriculture Canada, Research Station, 195 Dafoe Road, Winnipeg, Manitoba, R3T 2M9. Phytopathology 84:49-55. Accepted for publication 5 October 1993. Copyright 1994 Department of Agriculture, Government of Canada. DOI: 10.1094/Phyto-84-49.

Mitochondrial DNA (mtDNA) from the oat stem rust fungus Puccinia graminis f. sp. avenae is circular and 80.15 kb in length. Cloned restriction fragments from P. g. avenae race 3 and P. g. tritici race 126-Anz-6, 7, covering 99.7% of the rust mtDNA, were used for mapping the mitochondrial genome of P. g. avenae race 3. A physical map containing 148 restriction sites revealed no repeat structures. Cloned genes from Schizophyllum commune mtDNA were used in Southern hybridizations to determine the approximate location of four mitochondrial genes on the restriction map. No restriction fragment length polymorphism was detected between the mtDNAs of P. g. avenae races 3 and 8A, which differ for maternally inherited virulence on host lines with resistance gene Pg-3. The copy number of P. g. avenae mtDNA was estimated to be 19–29 per germinated urediniospore.