Phenazine-1-Carboxamide from Streptomyces Suppresses Phytophthora nicotianae Via CDC48-Targeted Mitochondrial Disruption

Phytophthora nicotianae is a plant-pathogenic oomycete, posing a major threat to global agriculture due to its destructive infections and difficulty of management. To explore the potential disease management using a biologically asked strategy, we investigated Streptomyces ardesiacus HL-06, which produces phenazine-1-carboxamide (PCN), a potent anti-oomycete compound that effectively suppresses P. nicotianae proliferation in vitro (EC 50 of 20 μg·mL -1 ) and reduces tobacco black shank severity by over 80% in field trials, outperforming the efficacy of commercial fungicides. Mechanistically, we have identified CDC48, a AAA+ ATPase essential for mitochondrial homeostasis, as the direct molecular target of PCN. Drug affinity responsive target stability (DARTS), molecular docking, and isothermal titration calorimetry revealed that PCN binds CDC48’s ATPase domain, disrupting mitochondrial protein quality control. This interaction leads to mitochondrial cristae loss, ATP synthase inhibition (52.99%), and reactive oxygen species (ROS) accumulation (13.06 - fold), ultimately triggering fungal apoptosis. This is the first report of a phenazine compound targeting a eukaryotic AAA+ ATPase, unveiling a novel mode of action against oomycete pathogens. Our findings integrate microbial ecology with chemical biology and position PCN as an eco-friendly alternative for sustainable crop protection.