Search for Fusarium species responsible for type A trichothecene contamination on natural grasses from a wetland ecosystem in Argentina

NICHEA M.J.; CENDOYA E.; ZACHETTI V.G.L.; TORRES A.M; RAMIREZ M.L.

Freising

Workshop; International Commision on Food Mycology. Whorshop 2016; 2016

International Commission on Food Mycology

Fusarium is considered a ubiquitous fungal genus commonly isolated from the majority of bioclimatic regions and ecosystems. Also, important Fusarium species can cause an array of plant diseases, produces mycotoxins and adversely affects animal and human health. In a previous work we have evaluate the biodiversity of Fusarium species and also the natural occurrence of their mycotoxins in native grasses collected from a wetland ecosystem located in the Chaco, Argentina. This region is one of the three highest biodiversity biomes of Argentina and covers part of the Parana and Paraguay rivers floodplain complex in the Eastern border of Chaco Province. The landscape is complex open water, aquatic vegetation, grasslands and gallery forests. This temperate grassland is used for grazing cattle. A total of 70 asymptomatic grasses belonging to 12 different genera all included in the Poaceae family were collected. The mycological analysis of the grasses revealed that all the samples were contaminated with Fusarium species in levels ranging from 60 to 100% regardless the grass genera analysed. The most common species found by comparison of the elongation factor 1-α sequences against those in the NCBI database and the Fusarium ID database was F. armeniacum (99 - 99,24 sequences similarity). But the result of the BLAST analyses was not mirrored in the phylogenies because all the isolates formed part of a group that did no include F. armeniacum type strains and any other type strain. The differences with F. armeniacum were supported by a main morphological difference, all our isolates produced microconiadia. Also all our isolates were able to produce type A trichothecenes mainly T-2, HT-2 and neosolaniol. To clarify the identity of these isolates a much profound morphological examination and a multilocus phylogenetic analysis are in progress.