Suppressed Protein Translation Caused by MSP-8 Defect Determines Fungal Multidrug Resistance with Fitness Cost
Antifungal resistance, particularly the rise in multidrug resistance, has become a critical public health concern, garnering substantial attention. In this study, we used experimental evolution with Neurospora crassa as a model and identified a novel multidrug-resistance gene, msp-8, which encodes a helicase. Deletion of msp-8 resulted in multidrug resistance in N. crassa, Aspergillus fumigatus and Fusarium verticillioides. Notably, the transcript levels of known drug target or efflux pump genes remained unchanged in the msp-8 knockout strain. However, this mutation compromised ribosomal function, thereby affecting protein translation. Importantly, inhibition of the protein translation process was found to enhance fungal resistance to azoles, Amphotericin B, and polyoxin B. Furthermore, deletion of msp-8 or inhibition of protein translation process decreased both intracellular ketoconazole accumulation and the membrane-binding AmB content, and lowered cellular ROS levels, resulting in multidrug resistance in fungi. Our study reveals a novel multidrug-resistance mechanism involving neither target nor efflux pump mutation, whereby dysfunction of helicase MSP-8 leads to suppressed protein translation, facilitating the development of multidrug resistance. This is the first report demonstrating that MSP-8 participates in protein translation and that inhibition of protein translation leads to multidrug resistance in fungi, offering new insights into the mechanisms of unknown resistant strains in clinical and environmental settings.