Análise filogenética e patogênica do agente causal da fusariose do abacaxizeiro no Brasil

Abstract

Fusarium guttiforme (sin. Fusarium subglutinans f. sp. ananas) is the causal agent of fusariosis on pineapple (Ananas comosus). This disease, considered the most important to this crop, has the exudation of gum as the most common symptom. Most of the published studies focus on the evaluation of the resistance of pineapple varieties against F. guttiforme. The estimative of genetic diversity in Fusarium populations is fundamental to understand the population structure, the movement of pathogen genetic material between producing regions, as well as understanding the processes that lead to resistance against pesticides and overcoming genetics resistance of pineapple cultivars. This fungus, which can be found in most regions of the country, does not have a known teleomorph and belongs to the Gibberella fujikuroi species complex, a group with heterogeneous characteristics. This study aimed: a) to obtain a collection of Fusarium isolates associated with pineapple fusariosis in the country; b) to reconstruct the phylogeny of Fusarium isolates that causes fusariosis on pineapple from Northeast and Southeast regions; c) to test the pathogenicity of isolates. DNA sequences of translation elongation fator 1-α (tef1) and calmodulin (cmd) were analyzed, and the history of the alleles was inferred by phylogenetic methods. Tef1 gene sequences were used to estimate the number of haplotypes from isolates collected in different regions. It was observed that the F. guttiforme is the causal agent of fusariosis on pineapple in Brazil, and the tef1 gene allowed a better infraspecific group distinction than cmd gene.