Circadian clock is critical for fungal pathogenesis by regulating zinc starvation response and secondary metabolism

Circadian clocks are known to modulate host immune responses to pathogen infections, yet their role in influencing pathogen pathogenesis remains unclear. Here, we investigated the role of circadian clocks in regulating the pathogenesis of the fungal pathogen <i>Fusarium oxysporum</i>, which has multiple genes homologous to the <i>Neurospora crassa frq</i> due to gene duplication events, with <i>Fofrq1</i> being the primary circadian clock gene. The pathogenesis of <i>F. oxysporum</i> in plants is controlled by its circadian clock, with infections causing severe disease symptoms at dawn. Notably, disruption of clock genes dramatically reduces fungal pathogenicity. Circadian clocks regulate the rhythmic expression of several transcription factors, including FoZafA, which enables the pathogen to adapt to zinc starvation within the plant, and FoCzf1, which governs the production of the toxin fusaric acid. Together, our findings highlight the critical roles of circadian clocks in <i>F. oxysporum</i> pathogenicity by regulating zinc starvation response and secondary metabolite production.