ABSTRACT
Fusarium tupiense, the main causal agent of mango malformation in Brazil, is described through a combination of morphological, biological and molecular markers. This new species belongs to the Gibberella fujikuroi species complex (GFSC) and has an anamorph morphologically similar to Fusarium mangiferae and F. sterilihyphosum. F. tupiense can be differentiated from other species in the G. fujikuroi species complex on the basis of sexual crosses, amplified fragment length polymorphism (AFLP) markers and partial sequences of the tef1 and tub2 genes. Female fertility for field isolates of F. tupiense appears to be low. PCR with primers specific for the mating type (MAT) alleles and sexual crosses identified this species as heterothallic with two idiomorphs. Female-fertile tester strains were developed for the identification of field strains of this species through sexual crosses.
Subject(s)
Fusarium/classification , Gibberella/classification , Mangifera/microbiology , Phylogeny , Plant Diseases/microbiology , Alleles , Amplified Fragment Length Polymorphism Analysis , Brazil , Crosses, Genetic , DNA, Fungal/genetics , Fusarium/cytology , Fusarium/genetics , Fusarium/isolation & purification , Genes, Mating Type, Fungal/genetics , Gibberella/cytology , Gibberella/genetics , Gibberella/isolation & purification , Inflorescence/microbiology , Plant Shoots/microbiology , Spores, Fungal/classification , Spores, Fungal/cytology , Spores, Fungal/genetics , Spores, Fungal/isolation & purificationABSTRACT
Pineapple (Ananas comosus) is native to South America and widely planted as a fruit crop in the tropics and sub-tropics. This plant is susceptible to a number of fungal diseases of which the most severe is fusariosis. The disease is caused by Fusarium guttiforme and occurs only in South and Central America. The occurrence of a similar disease on pineapples in South Africa has prompted a re-evaluation of the Fusarium sp. associated with pineapple fruit rot. Phylogenetic relationships of isolates from pineapples collected in Brazil and South Africa were assessed based on sequence data for the translation elongation factor-1-α, histone H3 and ß-tubulin gene regions. Analyses showed that the South African isolates represent a species distinct from Brazilian isolates. The South African isolates are characterised by a concentration of aerial mycelium at the centres of the colonies, different to the Brazilian isolates that have an even distribution of aerial mycelium. Both phylogenetic and morphological data show that the disease on pineapple in South Africa is caused by a new Fusarium species described here as F. ananatum sp. nov.