Characterization of the influence of carbon sources on fum1 gene expression in the fumonisin producer Fusarium verticillioides using RT - LAMP assay

Fusarium verticillioides is one of the major fumonisin producers. The ingestion of this mycotoxin represents a risk for both human and animal health. The development of F. verticillioides is associated with environmental conditions, especially carbon sources. We developed a reliable and fast reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay and determined fum1 gene expression upon growth of two F. verticillioides strains isolated from maize and wheat in Czapek's medium containing four different sugars as sole carbon sources. Fumonisin B1 (FB1) production was determined by LC-MS/MS analysis. High growth and production of FB1 were observed in fructose-containing medium for the strain that originated from maize. Less production of FB1 occurred using maltose as sole carbon source for both strains. The fum1 gene expression started between 2 and 4 days of incubation, and positive signals were detected prior to the initial production of FB1. The RT-LAMP assay was effective in the detection of fum1 gene expression at very early stages of F. verticillioides growth and allowed the prediction of FB1 formation. •RT-LAMP primers were designed to detect fum1 gene expression.•RT-LAMP results were detected directly after incubation by visible light.•RT-LAMP positive signals occur prior to the initial production of FB1.•Fructose induced high production of FB1 for F. verticillioides strain from maize.•A lower amount of FB1 was produced with maltose as carbon source by F. verticillioides strains.