Yazar "Myers, Kevin" seçeneğine göre listele

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    Population structure of Phytophthora infestans in Turkey reveals expansion and spread of dominant clonal lineages and virulence
    (Wiley, 2021) Gore, Mehmet E.; Altin, Nedim; Myers, Kevin; Cooke, David E. L.; Fry, William E.; Ozer, Goksel
    Late blight, caused by the oomycete Phytophthora infestans, is considered the most important and destructive disease of potato in Turkey. In this study, characterization of 367 isolates of P. infestans obtained from the potato-growing areas of the country was carried out to evaluate the pathogen population structure over the 2017-2019 production seasons. The isolates were characterized by numerous features including mating type, in vitro mefenoxam sensitivity, simple-sequence repeat (SSR) markers, and virulence against a set of potato differential lines. Most isolates were A2 mating type (353 isolates). Also, 68% of isolates were resistant to mefenoxam; the remainder were intermediate in their sensitivity and there were no sensitive isolates. SSR-based genotypic analysis of P. infestans populations showed a low genetic diversity. The 13_A2 clonal lineage predominated with a frequency of 92.1%, followed by 34_A1 (3.3%) and 37_A2 (2.7%). Genotypes 34_A1 and 37_A2 were detected only in 2019. This is the first report of 34_A1 and 37_A2 clonal lineages causing late blight disease of potato in Turkey. The most abundant virulence type was one overcoming resistance genes R1, R2, R3, R4, R6, R7, R10, and R11. These results emphasized that the migration of individuals and the asexual generation of subclonal differences were the main factors driving the population structure of P. infestans in Turkey.
  • Küçük Resim
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    Severe outbreaks of Phytophthora infestans on potato in Turkey caused by recent changes in the pathogen population structure
    (Springer, 2019) Göre, Mehmet Erhan; Altın, Nedim; Yaman, Tolga; Myers, Kevin; Çağlı, Abdurrahman; Cooke, David E.L.; Özer, Göksel
    Potato late blight, caused by Phytophthora infestans, has been the most damaging disease in Turkey since 2010. In this study, 127 isolates of P. infestans were obtained from the main growing areas of Turkey between 2015 and 2017. Their phenotypic and genotypic features were revealed and presented with those of reference isolates. These isolates were categorized by their mating type, in vitro mefenoxam sensitivity, mtDNA haplotype, RG57 DNA fingerprinting patterns, simple sequence repeat (SSR) markers, and aggressiveness on a set of potato differential lines. All isolates were of the A2 mating type and mtDNA haplotype Ia, were resistant to mefenoxam, and had RG57 and SSR fingerprints similar to the 13_A2 clonal lineage reported in Europe. This is the first report of 13_A2 in Turkey. Virulence abilities against potato resistance (R) genes R1, R2, R3, R4, R6, R7, R10, and R11 were observed in most of the isolates. The mating type ratios and SSR marker analysis indicate that in Turkey, the sexual reproduction of P. infestans is limited. These results underline that the movement of asexual individuals and the generation of sub-clonal difference are the factors driving the population structure of P. infestans in Turkey.