Prelecionista: Mariana Guimarães Silva
Orientador: Eduardo Seiti Gomide Mizubuti
Data: 24/07/24, às 16h
Local: Anfiteatro do ESB

Resumo: Populations of Phytophthora infestans, the causal agent of potato and tomato late blight, have been studied for a long time, but the epidemics still cause yield losses of both crops worldwide. In this study, the population of P. infestans occurring in Brazil between 2020 and 2024 was characterized using phenotypic and genotypic markers: mating type, mitochondrial DNA haplotypes, microsatellite genotypes, and sensitivity to mefenoxam. Additionally, the sensitivity of the population to different oomycides including the standards mefenoxam and mandipropamid was assessed by means of different methods: sporangia germination, mycelial growth, and sporulation on leaf disc. The population of P. infestans from Brazil is composed by mating types A1 and A2. However, A1/A2 isolates were identified in samples of Santa Catarina state. The Ia and Ib mitochondrial DNA haplotypes are occuring associated with potato and only the Ib occurs in tomato samples. Three clonal lineages are present here in Brazil, the EU_2_A1, EU_37_A2, and SA_1_A2, the new one. The European lineages occur associated with potato, and the new one (SA_1_A2) with tomato. The sensitivity to mefenoxam is varied among the isolates tested. Most isolates were intermediate and 5 isolates were resistant to mefenoxam. The majority of isolates were sensitive to mandipropamid and no one grew or sporulated at 10 μg/mL of the compound. This study updates the status of the population of P. infestans in Brazil.