The variability of Phytophthora infestans isolates collected from Estonian islands in the Baltic Sea

TY - JOUR

T1 - The variability of Phytophthora infestans isolates collected from Estonian islands in the Baltic Sea

AU - Runno-Paurson, Eve

AU - Agho, Collins Aimuaenvbosa

AU - Nassar, Helina

AU - Hansen, Merili

AU - Leitaru, Kätlin

AU - Hallikma, Tiit

AU - Cooke, David E L

AU - Niinemets, Ülo

N1 - Publisher Copyright: © 2024 The American Phytopathological Society.

PY - 2024/6/6

Y1 - 2024/6/6

N2 - Knowledge of a pathogen’s genetic variability and population structure is of great importance to effective disease management. In this study, 193 isolates of Phytophthora infestans collected from three Estonian islands were characterized over 3 years using simple sequence repeat (SSR) marker data complemented by information on their mating type and resistance to metalaxyl. In combination with SSR marker data from samples in the neighboring Pskov region of Northwest Russia, the impact of regional and landscape structure on the level of genetic exchange was also examined. Among the 111 P. infestans isolates from Estonian islands, 49 alleles were detected among 12 SSR loci, and 59 SSR multilocus genotypes were found, of which 64% were unique. The genetic variation was higher among years than that among islands, as revealed by the analysis of molecular variance. The frequency of metalaxyl-resistant isolates increased from 9% in 2012 to 30% in 2014, and metalaxyl resistance was most frequent among A1 isolates. The test for isolation by distance among the studied regions was not significant, and coupled with the absence of genetic differentiation, the result revealed gene flow and the absence of local adaptation. The data are consistent with a sexual population in which diversity is driven by an annual germination of soil-borne oospores. The absence of shared genotypes over the years has important implications when it comes to the management of diseases. Such population diversity can make it difficult to predict the nature of the outbreak in the coming year as the genetic makeup is different for each year.

AB - Knowledge of a pathogen’s genetic variability and population structure is of great importance to effective disease management. In this study, 193 isolates of Phytophthora infestans collected from three Estonian islands were characterized over 3 years using simple sequence repeat (SSR) marker data complemented by information on their mating type and resistance to metalaxyl. In combination with SSR marker data from samples in the neighboring Pskov region of Northwest Russia, the impact of regional and landscape structure on the level of genetic exchange was also examined. Among the 111 P. infestans isolates from Estonian islands, 49 alleles were detected among 12 SSR loci, and 59 SSR multilocus genotypes were found, of which 64% were unique. The genetic variation was higher among years than that among islands, as revealed by the analysis of molecular variance. The frequency of metalaxyl-resistant isolates increased from 9% in 2012 to 30% in 2014, and metalaxyl resistance was most frequent among A1 isolates. The test for isolation by distance among the studied regions was not significant, and coupled with the absence of genetic differentiation, the result revealed gene flow and the absence of local adaptation. The data are consistent with a sexual population in which diversity is driven by an annual germination of soil-borne oospores. The absence of shared genotypes over the years has important implications when it comes to the management of diseases. Such population diversity can make it difficult to predict the nature of the outbreak in the coming year as the genetic makeup is different for each year.

KW - late blight

KW - population structure

KW - SSR markers

KW - mating type

KW - metalaxyl resistance

KW - potato

KW - the Baltic Sea islands

UR - https://www.scopus.com/pages/publications/85194091006

U2 - 10.1094/PDIS-07-23-1399-RE

DO - 10.1094/PDIS-07-23-1399-RE

M3 - Article

C2 - 38127634

SN - 0191-2917

VL - 108

SP - 1645

EP - 1658

JO - Plant disease

JF - Plant disease

IS - 6

ER -