Emerging Roles of tRNA Modifications in Translational Adaptation of Human Fungal Pathogens.

Invasive fungal infections can be life-threatening, particularly in patients with impaired immunity, yet treatment remains limited to a few antifungal drug classes. During infection, fungal pathogens encounter changes in temperature, nutrient availability, immune pressure and drug exposure that challenge their growth and survival. tRNA modifications may contribute to adaptation by supporting tRNA stability, aminoacylation and codon decoding. Studies in Aspergillus fumigatus, Candida albicans and Cryptococcus neoformans have linked conserved tRNA-modification pathways to fungal development, host interaction, stress adaptation, virulence and the response to 5-fluorocytosine, with evidence ranging from genetic and infection phenotypes to biochemical characterization of modification reactions. In this Review, we examine how these studies connect modification chemistry and substrate tRNAs with translation, protein output and infection phenotypes. We also draw on mechanistic studies from model organisms and plant-pathogenic fungi to clarify translational links that remain unresolved in human fungal pathogens. We conclude by discussing when tRNA-modification pathways become functionally limiting under host-associated conditions and how they may alter antifungal responses.