RNA-seq Analysis of RFX1-dependent Genes in Fusarium graminearum Z-3639

Fusarium graminearum is a major pathogen of Fusarium head blight in wheat, barley, and rice, as well as ear rot and stalk rot in maize. Regulatory Factor X (RFX) transcription factors are well-conserved in animals and fungi, but their functions are diverse, ranging from DNA-damage response to ciliary gene regulation. We investigated the role of the sole RFX transcription factor, RFX1, in F. graminearum. Deletion of rfx1 resulted in multiple defects in hyphal growth, conidiation, virulence, and sexual development. Deletion mutants of rfx1 were more sensitive to various types of DNA damage than the wild-type strain. Septum formation was inhibited and micronuclei were produced in the rfx1 deletion mutants. The results of the neutral comet assay demonstrated that disruption of rfx1 function caused spontaneous DNA double-strand breaks. To understand regulatory mechanisms of rfx1 in F. graminearum, we obtained and analyzed genome-wide transcription profiles generated from the RNA-sequencing data of the wild-type and Δrfx1 strains. RNA-sequencing-based transcriptomic analysis revealed that RFX1 suppressed the expression of many genes, including genes for the repair of DNA damage.