Caracterização molecular de isolados de Fusarium oxysporum f. sp. cubense do Nordeste, Sudeste e Sul do Brasil

Abstract

The banana production is a major component of Brazilian agribusiness. However, several problems limit the production of this crop. Panamá disease, caused by the fungus Fusarium oxysporum f. sp. cubense (Foc), is a major concern since the only control measure is the use of resistant varieties. Foc is endemic to all producing regions, and is soilborne, which hinders this disease’s management. The objective of this study was to understand the population structure of Foc in different producing regions of Brazil. Therefore, 214 Foc isolates from the Northeast, Southeast and Southern regions were used and characterised by microsatellite markers (SSR). The markers sorted the isolates into 52 distinct haplotypes. There was no correlation between the genetic and geographical distances for the Southeast and Northeast region. However, a moderate significant the correlation was moderate and highly significant for the Southern region. The AMOVA analysis showed that 67.9% of the total variation occurred within the states. Based on the isolates’ genetic constitution, 16 genetic clusters were formed. These were distributed into different geographical regions and cultivars from which they were obtained. Results indicate that isolates from different states comprise a single population, which is predominantly clonal. Moreover, the genetic differences between isolates are due to the mixture of different clonal lineages. The encountered diversity points to the need for additional studies since that characteristic might be related to Foc’s evolutionary potential and possibly to its ability to overcome the resistance of by breeding programs’ generated cultivars.