Fumonisin biosynthesis and FUM gene expression by Fusarium proliferatum strains in a wheat-based media under different abiotic conditions

CENDOYA E.; BARREAU C.; PINSON-GADAIS L.; FARNOCHI M.C.; RAMIREZ M.L.; RICHARD-FORGET F.

Freising

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

International Commission on Food Mycology

Fumonisins are toxic fungal metabolites produced mainly by Fusarium species. Fumonisin B1 is the most significant in terms of occurrence and toxicity; it can cause severe disorders in animal?s health and has been epidemiologically associated with oesophageal cancer and neural tube defects in some human populations. Several Fusarium species are able to produce fumonisins, but the two most important ones are F. verticillioides and F. proliferatum, which are common fungi associated with maize, but can also be isolated from other substrates such as wheat. Wheat is the most important cereal consumed by the Argentine population. Fungal growth and mycotoxin production result from the complex interaction of several factors and, therefore, an understanding of each factor involved is essential to predict and prevent mycotoxin development. The aim of this study was to analyze the effects of abiotic factors, temperature and water activity (aW), on growth, fumonisins biosynthesis and FUM8 and FUM19 gene expression in 3 F. proliferatum strains isolated from durum wheat in Argentina, using a wheat-based medium. The effect of both aW and temperature on growth was examined in vitro, the effect on fumonisin production was examined by HPLC-MS-MS, and the effect on FUM gene expression was quantified by specific real-time reverse transcriptase-PCR assays. Although all isolates showed similar profiles of growth, the fumonisin production profiles were slightly different. Regarding FUM gene expression, both FUM8 and FUM19 showed similar behavior in all tested conditions. Both genes where repressed when there was not fumonisin production, with the exception of the control condition at 15 °C, where there was no fumonisin biosynthesis but gene expression was not repressed, suggesting that genes were expressed in the same way than in the control condition at 25 °C for all tested strains. This study provides useful base line data on conditions representing a high and a low risk for contamination of wheat by fumonisins.