Genetic structure and mating type analysis of the Pyricularia oryzae population causing widespread epidemics in southern Brazil

Genetic structure and mating type analysis of the Pyricularia oryzae population causing widespread epidemics in southern Brazil

Blast is a major disease of rice in Brazil, the largest rice-producing country outside Asia. This study aimed to assess the genetic structure and mating-type frequency in a contemporary Pyricularia oryzae population, which caused widespread epidemics during the 2012/13 season in the Brazilian lowlan...

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Bibliographic Details
Published in:Tropical plant pathology Vol. 41; no. 5; pp. 297 - 305
Main Authors: D’Ávila, Leilane S., Lehner, Miller S., Filippi, Maria Cristina C., Scheuermann, Klaus K., Del Ponte, Emerson M.
Format: Journal Article
Language:English
Published: Cham Springer International Publishing 01-10-2016
Springer Nature B.V
Subjects:
Biomedical and Life Sciences
Cultivars
Differentiation
Discriminant analysis
Epidemics
Farming
Gene polymorphism
Genetic structure
Genotype & phenotype
Genotypes
Leaves
Life Sciences
Mating
Original Article
Plant Pathology
Polymorphism
Population
Rice blast
Rice fields
Simple sequence repeats
Subpopulations
Brazil
Microsatellite
Population structure
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Summary:Blast is a major disease of rice in Brazil, the largest rice-producing country outside Asia. This study aimed to assess the genetic structure and mating-type frequency in a contemporary Pyricularia oryzae population, which caused widespread epidemics during the 2012/13 season in the Brazilian lowland subtropical region. Symptomatic leaves and panicles were sampled at flooded rice fields in the states of Rio Grande do Sul (RS, 34 fields) and Santa Catarina (SC, 21 fields). The polymorphism at ten simple sequence repeats (SSR or microsatellite) loci and the presence of MAT1-1 or MAT1-2 idiomorphs were assessed in a population comprised of 187 isolates. Only the MAT1-2 idiomorph was found and 162 genotypes were identified by the SSR analysis. A discriminant analysis of principal components (DAPC) of SSR data resolved four genetic groups, which were strongly associated with the cultivar of origin of the isolates. There was high level of genotypic diversity and moderate level of gene diversity regardless whether isolates were grouped in subpopulations based on geographic region, cultivar host or cultivar within region. While regional subpopulations were weakly differentiated, high genetic differentiation was found among subpopulations comprised of isolates from different cultivars. The data suggest that the rice blast pathogen population in southern Brazil is comprised of clonal lineages that are adapting to specific cultivar hosts. Farmers should avoid the use of susceptible cultivars over large areas and breeders should focus at enlarging the genetic basis of new cultivars.
ISSN:1983-2052
1982-5676
1983-2052
DOI:10.1007/s40858-016-0101-9