Qip gene in Fusarium oxysporum is required for normal hyphae morphology and virulence

Ribonucleic acid (RNA)-silencing mechanisms exist in many eukaryotes to regulate a variety of biological processes. The known molecular components are related to Dicers, Argonautes and RNA-dependent RNA polymerases. Previous biochemical studies have also suggested that Qip, with an exonuclease domain, facilitates the conversion of duplex small interfering RNAs into single strands. In our study, the Qip gene in Fusarium oxysporum was disrupted using homologous recombination technology. The deletion of the Qip gene resulted in a decrease in colony growth rates but increased the number of branches. Additionally, the Δ Qip mutant had a reduced pathogenicity in cabbage. Our results show Qip gene in F. oxysporum is required for normal hyphae morphology and virulence. The mutant will be useful for elucidating the relationship between the RNA-silencing mechanism and hyphal growth and development in F. oxysporum .