Diversidade de espécies filogenéticas e biológicas do complexo Fusarium solani-fssc no Brasil

Abstract

The Fusarium solani species complex (FSSC) is represented by around 60 species phylogenetically distinct. Through these studies we intended to investigate: (i) how many phylogenetic lineages, already identified in the FSSC, are present in a collection of 52 isolates from various geographical origens, different plants and soils of Brazil? (ii) are there phylogenetic lineages not identified yet? (iii) from the assessed strains, the usage of phylogenetic and biological concepts, when complemented, may help in the identification of species in the complex? These studies aimed to: (i) verify the diversity of species of the complex in Brazil through phylogenetic analysis based on RPB2 and EF-1α datasets; (ii) to develop primers for identification the mating types of the isolates in FSSC; and (iii) identify the presence of biological species among studied isolates by crossing in the laboratory. Thirty-seven isolates from Brazil were grouped in 12 distinct phylogenetic lineages of the clade 3 in the FSSC, of which 10 lineages are unpublished records. F. keratoplasticum has already been reported in Brazil in association with superficial mycosis in humans and was found in this study in association with black pepper. The lineages FSSC 5, FSSC 7, FSSC 9, FSSC 20 and FSSC 34 were represented by isolates obtained from various plants and soils, although they have already been described in association with humans and animals. Nine homothallic isolates are associated with plant material and were grouped in three distinct phylogenetic lineages: FSSC 8 (Noecosmospora clade), FSSC 21 (F. striatum) and FSSC 33. Biological species were identified by developed primers in the present study to determine the mating type for the species of FSSC. After determination of mating type, isolates of the same phylogenetic lineage were subjected to the crossing in the laboratory. Two phylogenetic lineages identified also represented distinct biological species: (i) in the FSSC 23 (MP-II, f.sp. batatas), fertile crossings were obtained among isolates of black pepper from Brazil and isolate of MP-II, being the first report of that MP in the country; and (ii) FSSC 31 represents a phylogenetic and biological specie which causes disease in black pepper. From two known MP, MP-IV, f.sp. xanthoxyli and MP-V, F. petroliphilum, were determined the mating types of the isolates tester by developed primers in this study and, fertile crossings were obtained among them. A novel MP was identified among isolates pathogenic of soybean. From homothallic isolates was amplified both idiomorphs. There is in Brazil a wide diversity of biological and phylogenetic lineages of the FSSC associated with economically important plants.