Identification of a species-specific protein of toxigenic Fusarium verticillioides

Fusarium verticillioides is a primary corn pathogen and the main producer of fumonisins, a group of toxic secondary metabolites that can cause human and animal health hazards. In humans, epidemiological studies have associated fumonisins with esophageal and liver cancer and have been classified by the International Agency for Research on Cancer – IARC in group 2B (possibly carcinogenic to humans). The development of a rapid, sensitive and specific method to detect this fungus is essential and immunological detection is a promising approach. The discovery, identification and characterization of species-specific antigens are important for the development of a specific immunological technique. Therefore, the objective of this study was to identify the 67 kDa protein (p67) of F. verticillioides exoantigen which shows high potential to be a species-specific antigen. p67 was identified by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) and by in-gel analysis of the enzymatic activity (amylase and protease) using polyacrylamide gel co-polymerized with starch, gelatin, and bovine serum albumin. The analysis of in-gel trypsin digested p67 by mass spectrometry revealed two possible proteins: the protein related to aminopeptidase Y precursor of F. fujikuroi and the putative glucoamylase GMY2 of F. verticillioides. In order to confirm which of these proteins the p67 is, both the enzymatic activities were evaluated and showed that this protein presents an amylase activity indicating that p67 is the putative glucoamylase GMY2 of F. verticillioides.