A putative ABC transporter gene, ZRA1, is required for zearalenone production in Gibberella zeae

Abstract

Zearalenone (ZEA) is a secondary metabolite produced by various Fusarium species and causes estrogenic disorders in humans and animals. Recent studies have identified the ZEA biosynthesis gene cluster in F. graminearum, but other genes such as transporters responsible for ZEA export have not been identified in the cluster. In this study, we performed microarray analyses from the wild-type strain with and without ZEA supplementation and ZEA-nonproducing strain zeb2 to discover other genes responsible for ZEA biosynthesis. Three putative ABC transporters were significantly down-regulated in the zeb2 and were under positive regulation of the ZEB2 gene, which functions as a transcriptional activator for ZEA production in this fungus. However, only one gene (ZRA1) was found to be up-regulated by 20-fold in the wild-type strain supplemented with ZEA, and deletion of ZRA1 resulted in reduced ZEA production. Deletions of the other two genes showed similar ZEA productions as the wild-type strain. ZRA1 localized to the plasma membrane and vacuoles indicating possible roles of ZRA1 as a transporter. This study indicated that ZRA1 is involved in ZEA production and shares a common regulatory mode with ZEA cluster genes by ZEB2.