FUM and BIK gene expression contribute to describe fumonisin and bikaverin synthesis in Fusarium verticillioides

► We studied water activity effects on fumonisin and FUM3, FUM8, FUM13, FU14 genes. ► We studied water activity effects on bikaverin production and BIK1 expression. ► Fumonisin production and FUM gene expression were enhanced at high water activity. ► Bikaverin and BIK1 were enhanced in the same conditions as fumonisin and FUM genes. ► FB3/FB1 ratio was higher when FUM14 was more highly expressed than FUM3.