Phytopathology (2006) 96, S34-S35

N. Feau, M. Bourassa, D.L. Joly, R.C. Hamelin, A. Andrieux, B. Barrès and P. Frey (2006)
Intercontinental genetic structure of the poplar rust Melampsora medusae f. sp. deltoidae
Phytopathology 96 (6 suppl.), S34-S35
Abstract: Migrations of plant pathogens into regions or continents previously free of the disease are recent events relative to the co-evolutionary history of host and pathogen which occurred in the endemic area. Due to the stochastic nature of long-distance dispersal, founder populations are likely to represent a subset of the variation in the center of origin and are not expected to be in equilibrium. A genetically characterized set of SSCP (Single-Strand Conformational Polymorphisms; 2 loci) and microsatellites (4 loci) developed for the poplar leaf rust fungus Melampsora medusae f. sp. deltoidae is used on an extensive worldwide collection in order to infer migration events and sources of introductions across three continents. Isolates from North America exhibited a very high genomic diversity with multiple alleles per locus (4, 7, and 4 to 9 alleles for each of two SSCP and four microsatellite loci, respectively). In contrast, a clonal structure was observed in the European and South-African populations. African and European alleles represent a subset of the allelic diversity present in North America. This is consistent with scenarios of long-distance and independent migration events.
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Database assignments for author(s): Pascal Frey, Richard C. Hamelin

Research topic(s) for pests/diseases/weeds:
molecular biology - genes
surveys/sampling/distribution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Melampsora medusae	Poplar/aspen (Populus)	South Africa