Staurosporine Targets Mitochondrial Regulator VdAtuA3 to Disrupt Mitochondrial Homeostasis to Control Verticillium Wilt.

Mitochondria serve as cellular powerhouses that generate ATP via electron transport chain complexes and orchestrate metabolism-apoptosis cross-talk, yet genes maintaining mitochondrial homeostasis remain underexplored as antifungal targets. In this study, a previously uncharacterised protein VdAtuA3 was identified as a novel interactor with VdNuo1 (NADH: ubiquinone oxidoreductase 24-kDa subunit), defining a regulatory axis for the mitochondrial respiratory chain in Verticillium dahliae. Notably, VdNuo1 is highly conserved across plants, animals, and humans, consistent with its essential role in respiration, whereas VdAtuA3 homologues in non-fungal organisms share very low sequence similarity. Moreover, Y2H assays confirmed no interaction between Nuo1 and AtuA homologues from above organisms, indicating that this regulatory axis is specific to V. dahliae. The pathogen virulence factor VdAtuA3 and VdNuo1 co-regulate oxidative phosphorylation and superoxide detoxification, thereby promoting mitochondrial homeostasis. Staurosporine (STS), a natural microbial product, targets VdAtuA3, inhibiting its function and reducing the interaction between VdAtuA3 and VdNuo1, inducing mitochondrial dysfunction in V. dahliae, and suppressing its growth effectively controls Verticillium wilt. STS shows high efficacy with minimal off-target toxicity and can be safely applied to cotton, zebrafish, and human cells at fungistatic doses. Its broad-spectrum activity against multiple filamentous fungi, consistent with its high binding affinity to AtuA homologues from various filamentous fungi as demonstrated by molecular docking and functional complementation assays, further supports its potential as a promising antifungal agent. Our study provides a proof-of-concept for targeting pathogen-specific virulence factors that regulate mitochondrial homeostasis as a novel strategy to manage fungal plant pathogens.