LAUSR

Zearalenone (ZEN) is a mycotoxin produced by some species of Fusarium, especially by Fusarium graminearum and F. culmorum. It is a significant contaminant of maize, barley, wheat and other cereals. ZEN is implicated in reproductive problems in experimental animals and livestock and is classified as a non-steroidal estrogen or mycoestrogen. The carcinogenicity, genotoxicity, hepatotoxicity, haematotoxicity and immunotoxicity of ZEN were also reported. ZEN is biosynthesized from acetate-polymalonate pathway leading to nonaketide precursor which then subjected to different cyclizations and modifications. At the molecular level, a 50 kb gene cluster containing 11 genes was previously identified in F. graminearum. But ZEN biosynthesis is limited to four genes within this cluster: two polyketide synthase genes PKS4 and PKS13, gene similar to isoamyl alcohol oxidase (ZEB1) and a regulatory protein gene (ZEB2). This review covers the updated information concerning the molecular biology of ZEN biosynthesis as well as the proposed mechanism of its biosynthetic pathway. We also report the molecular regulation of its biosynthesis. Moreover, molecular methods developed for the specific detection and quantification of ZEN producing species are detailed in this review.