Autophagy as a multi-scale architect of fungal development and pathogenicity: membrane dynamics, multilayer...

Autophagy is a conserved membrane-trafficking pathway traditionally viewed as a nonspecific nutrient recycling mechanism. However, recent advances across diverse fungal systems, from plant pathogens to human opportunistic fungi and entomopathogenic species, have revealed autophagy as a central regulatory hub that orchestrates fungal development, virulence, and host interaction at multiple biological scales. This review provides a comprehensive and critical synthesis of these emerging insights. At the nanoscale, the discussion explores how autophagosome biogenesis depends on the spatially precise delivery of PtdIns4P by oxysterol-binding proteins, the dual function of the TRAPPIII vesicle-tethering complex, and the retromer-mediated sorting of vacuolar proteases. At the organelle level, the interplay between selective autophagy (mitophagy, lipophagy, pexophagy) and a newly discovered layer of epitranscriptomic, transcriptional, and post-translational regulation, comprising m⁵C RNA methylation of core ATG transcripts, FOX transcription-factor-driven gene activation, and nuclear acetylation of Atg8, respectively, is examined. At the macroscale, the review highlights how autophagy-dependent cell death and ferroptosis cooperate to drive appressorium maturation in Magnaporthe oryzae, and presents direct biochemical evidence for crosstalk between the cell wall integrity MAPK cascade and the autophagy machinery, a paradigm that challenges the long-standing view of these pathways as parallel systems. Further discussion addresses how autophagy deficiency triggers Mincle-dependent host immunity in Cryptococcus neoformans and how entomopathogenic Cordyceps militaris co-opts autophagy for fruiting body morphogenesis. We emphasize that the direct biochemical evidence for several of these mechanisms, notably CWI-MAPK/Atg4 crosstalk and autophagy-ferroptosis coupling, currently derives largely from Magnaporthe oryzae, and we distinguish such established mechanisms from cross-species extrapolations throughout. Finally, Atg4 inhibitors are evaluated as a promising class of broad-spectrum antifungal agents, and key directions for future research, including spatiotemporal imaging, multi-omics validation, and translational antifungal strategies, are identified.