Targeting the transcription factor AbaA: a potential strategy for inhibiting fungal conidiation and enhancing crop safety

Abstract Fusarium oxysporum is a devastating soil-borne pathogen that causes wilt diseases in numerous economically important crops. Conventional fungicides typically target essential cellular processes, exerting strong selection pressure for the rapid development of resistance. In this study, we investigated the key conidiation regulator FolAbaA and identified, through virtual screening, two small-molecule compounds (G305-0126 and 8019-6157) that specifically disrupt conidiation in Fusarium oxysporum f. sp. lycopersici ( Fol ) without affecting basal fungal growth. Conidiation inhibition assays demonstrated that both compounds effectively inhibit Fol conidiation, with EC 50 values of 1.827 μM and 0.8849 μM, respectively. Further analysis confirmed that both compounds bind directly to FolAbaA and downregulate three critical downstream genes involved in conidiation. Additionally, the compounds exhibited broad-spectrum antifungal activity against Magnaporthe oryzae and Botrytis cinerea, while no phytotoxic effects were observed on treated plant seedlings. In summary, our work establishes FolAbaA as a promising target for the development of novel fungicides and provides a foundation for further elucidation of conidiation regulatory networks.