Naringenin Inhibits the Growth of <i>Diaporthe citri</i> by Targeting Fungal Glucokinase

<i>Diaporthe citri,</i> a pathogenic fungus affecting citrus, has developed resistance to chemical fungicides. Developing botanical fungicides is crucial for effectively controlling this pathogen. In this study, we found naringenin, a natural flavonoid, has inhibitory activity against <i>D. citri</i>. Target screening identified <i>D. citri</i> glucokinase (DcGCK), a key enzyme in glucose metabolism, as a novel target of naringenin. Further binding analysis confirmed the high-affinity binding between DcGCK and naringenin. Specifically, naringenin competitively binds to the active pocket of DcGCK, disrupting binding of glucose to DcGCK and thereby inhibiting its activity. Deletion of <i>DcGCK</i> significantly suppressed <i>D. citri</i> growth and pathogenicity. Moreover, transcriptome and metabolite analyses demonstrated that naringenin disrupts sugar metabolism in <i>D. citri</i>. Our results elucidate that naringenin directly targets DcGCK and interferes with fungal sugar metabolism. This reveals a novel mechanism by which naringenin inhibits pathogenic fungal growth and provides a new strategy to protect plants from <i>D. citri</i>.