Molecular Ecology (2008) 17, 4446-4458

Michael G. Milgroom, Kiril Sotirovski, Domenico Spica, Joanne E. Davis, Marin T. Brewer, Milko Milev and Paolo Cortesi (2008)
Clonal population structure of the chestnut blight fungus in expanding ranges in southeastern Europe
Molecular Ecology 17 (20), 4446-4458
Abstract: Expanding populations are often less genetically diverse at their margins than at the centre of a species' range. Established, older populations of the chestnut blight fungus, Cryphonectria parasitica, are more variable for vegetative compatibility (vc) types than in expanding populations in southeastern Europe where C. parasitica has colonized relatively recently. To test whether vc types represent clones, we genotyped 373 isolates of C. parasitica from southern Italy, Romania, Bulgaria, Macedonia, Greece and Turkey using 11 sequence-characterized amplified region (SCAR) markers. Ten SCAR loci and six vegetative incompatibility (vic) loci were polymorphic in these samples. These populations are clonal by all criteria tested: (i) among 373 isolates, we found only eight multilocus haplotypes, and the same haplotypes were found in multiple countries, sometimes separated in time by as much as 12 years; (ii) the number of haplotypes observed was significantly less than expected under random mating; (iii) populations are in linkage disequilibrium; (iv) the two sets of independent markers, SCARs and vc types, are highly correlated; and (v) sexual structures of C. parasitica were found only in Bulgaria and Romania. One mating type (MAT-1) was found in 98% of the isolates sampled. In contrast, a population in northern Italy, in the central part of the range in Europe, had 12 multilocus haplotypes among 19 isolates. The spread of a few clones could be the result either of founder effect and restricted migration, or these clones have greater fitness than others and spread because they are better adapted to conditions in southeastern Europe.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Michael G. Milgroom, Paolo Cortesi, Marin Talbot Brewer, Kiril Sotirovski

Research topic(s) for pests/diseases/weeds:
molecular biology - genes
population dynamics/ epidemiology

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Cryphonectria parasitica		Bulgaria
	Cryphonectria parasitica		Greece
	Cryphonectria parasitica		Italy
	Cryphonectria parasitica		North Macedonia
	Cryphonectria parasitica		Romania
	Cryphonectria parasitica		Turkey