Characterization of Epicoccum isolates obtained from Argentinean sorghum grain samples

Sorghum has numerous agronomic advantages, a great economic importance in food production and various industrial applications. Its consumption has increased in the last ten years and probably its importance may even increase in the future, considering its relationship with global warming since this plant is less demanding with water. However, its productivity is affected by various fungal diseases with the production of mycotoxins that cause great economic losses. Alternaria, Epicoccum and Pyricularia genera are the main fungal contaminants in sorghum grains, and recognized producers of tenuazonic acid, a mycotoxin previously found in assayed sorghum samples in the Mycology and Mycotoxicology laboratory belonging to the Center for Research and Development in Industrial Fermentations. Fungal isolates obtained from these sorghum grains from the National Institute of Agricultural Technology (INTA, Manfredi, Córdoba, Argentina) were characterized using a polyphasic approach based on morphological and genetic characteristics and in the ability to produce mycotoxins. Morphological analysis suggested the identity of Epicoccum sorghinum, which was later confirmed by molecular analysis. The ability of these isolates to produce tenuazonic acid was evaluated and it was determined that 65% of the studied isolates produced tenuazonic acid at variable levels. This is the first study that provides a molecular approach to E. sorghinum isolates in Argentina and clearly confirms the wide genetic and phenotypic variability previously reported for this species in other countries. The presence of these tenuazonic acid-producing isolates in sorghum grains represent an economic and health problem for Argentina that it is considered one of the main exporters worldwide.