Barnes, Irene , Kirisits, Thomas , Wingfield, Michael J. , Wingfield, Brenda D .
The anthropogenic movement of the invasive pine pathogen, Dothistroma septosporum, is reflected in its genetic diversity.
Dothistroma septosporum is a haploid fungal pathogen that causes a serious needle blight disease of pines, particularly on exotic Pinus radiata in the Southern Hemisphere. During the course of the last decade, the pathogen has also resulted in unexpected and severe epidemics on native and non-native pines in the Northern Hemisphere. The origin of D. septosporum is unknown but it has been hypothesized to be native to the Himalayas and/or Central America. The aim of this study was to determine the population diversity and structure of a collection of D. septosporum isolates from 14 countries on six continents using microsatellite markers. High genetic diversity was found in collections from the Northern Hemisphere countries, where pines are native and two mating type genes are present. Most of the populations from Europe (Austria, Czech Republic and Hungary) were randomly mating showing little differentiation and high gene flow. Similar results were obtained for the North American (U.S.A) and Asian (Bhutan) populations. Isolates from most of the Southern Hemisphere countries (New Zealand, Australia and Chile) had low genetic diversity and were represented by a single mating type. However, populations from Africa (Kenya and South Africa), which have had longer histories of pine introductions, had relatively high genetic diversity and were randomly mating. The results are consistent with a Northern Hemisphere origin of D. septosporum and the patterns of diversity reflect the movement of germplasm and the expansion of pine cultivation in the Southern Hemisphere.
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1 - Forestry and Agricultural Biotechnology Institute (FABI), Department of Genetics, University of Pretoria, Pretoria, 0002, South Africa
2 - Institute of Forest Entomology, Forest Pathology and Forest Protection, Department of Forest and Soil Sciences (DFS), University of Natural Resources and Applied Life Sciences, Vienna (BOKU), Vienna, Austria
3 - Forestry and Agricultural Biotechnology Institute (FABI), Department of Genetics,, University of Pretoria, Pretoria, 0002, South Africa
4 - Forestry and Agricultural Biotechnology Institute (FABI), Department of Genetics, University of Pretoria, Pretoria, 0002, South Afica
mating type genes.
Presentation Type: Oral Paper:Papers for Topics
Location: Cottonwood D/Snowbird Center
Date: Tuesday, July 28th, 2009
Time: 11:15 AM