TY - JOUR
T1 - Global hierarchical gene diversity analysis suggests the fertile crescent is not the center of origin of the barley scald pathogen Rhynchosporium secalis
AU - Zaffarano, Pascal L.
AU - McDonald, Bruce A.
AU - Zala, Marcello
AU - Linde, Celeste C.
PY - 2006/9
Y1 - 2006/9
N2 - A total of 1,366 Rhynchosporium secalis isolates causing scald on barley, rye, and wild barley (Hordeum spontaneum) were assayed for restriction fragment length polymorphism loci, DNA fingerprints, and mating type, to characterize global genetic structure. The isolates originated from 31 field populations on five continents. Hierarchical analysis revealed that more than 70% of the total genetic variation within regions was distributed within a barley field. At the global level, only 58% of the total genetic variation was distributed within fields, while 11% was distributed among fields within regions, and 31% was distributed among regions. A significant correlation was found between genetic and geographic distance. These findings suggest that gene flow is common at the local level while it is low between regions on the same continent, and rare between continents. Analyses of multilocus associations, genotype diversity, and mating type frequencies indicate that sexual recombination is occurring in most of the populations. We found the highest allele richness in Scandinavia followed by Switzerland. This suggests that R. secalis may not have originated at the center of origin of barley, the Fertile Crescent, nor in a secondary center of diversity of barley, Ethiopia.
AB - A total of 1,366 Rhynchosporium secalis isolates causing scald on barley, rye, and wild barley (Hordeum spontaneum) were assayed for restriction fragment length polymorphism loci, DNA fingerprints, and mating type, to characterize global genetic structure. The isolates originated from 31 field populations on five continents. Hierarchical analysis revealed that more than 70% of the total genetic variation within regions was distributed within a barley field. At the global level, only 58% of the total genetic variation was distributed within fields, while 11% was distributed among fields within regions, and 31% was distributed among regions. A significant correlation was found between genetic and geographic distance. These findings suggest that gene flow is common at the local level while it is low between regions on the same continent, and rare between continents. Analyses of multilocus associations, genotype diversity, and mating type frequencies indicate that sexual recombination is occurring in most of the populations. We found the highest allele richness in Scandinavia followed by Switzerland. This suggests that R. secalis may not have originated at the center of origin of barley, the Fertile Crescent, nor in a secondary center of diversity of barley, Ethiopia.
KW - Coevolution
KW - Host specialization
KW - Population genetics
KW - Speciation
UR - http://www.scopus.com/inward/record.url?scp=33748066003&partnerID=8YFLogxK
U2 - 10.1094/PHYTO-96-0941
DO - 10.1094/PHYTO-96-0941
M3 - Article
SN - 0031-949X
VL - 96
SP - 941
EP - 950
JO - Phytopathology
JF - Phytopathology
IS - 9
ER -