AoVps18 regulates sporulation, trap morphogenesis, and nematode predation by modulating vacuole assembly and attractant synthesis in Arthrobotrys oligospora.

Abstract

Vacuoles are essential organelles in eukaryotic cells, playing key roles in cellular homeostasis through nutrient sensing, osmoregulation, and autophagy. In filamentous fungi, vacuole dynamics are crucial for mycelial growth, stress response, and pathogenicity. The vacuolar functions and their regulation in nematode-trapping (NT) fungi remain poorly understood. Here, we characterized a vacuolar protein sorting (Vps) protein Vps18 (AoVps18) in a typical NT fungus Arthrobotrys oligospora, which is required for the proper regulation of mycelial growth, trap formation, and sporulation. Through integrated phenotypic and molecular analyses, we established that AoVps18 physically interacts with core mitogen-activated protein kinase (MAPK) signaling components (AoSte12 and AoFus3) to coordinate predation-related cellular processes, including vacuole assembly, mitochondrial dynamics, and lipid droplet accumulation. Notably, we identified a TGAAAC regulatory motif in the Aovps18 promoter, suggesting direct transcriptional control by the MAPK effector, AoSte12. RNA sequencing and metabolomics further revealed that AoVps18 is involved in regulating multiple cellular processes and synthesizing compounds critical for the chemotaxis of nematodes toward A. oligospora. Overall, these findings elucidate the regulatory mechanisms by which AoVps18 coordinates vacuolar function with trap morphogenesis and mycelial growth in NT fungi, advancing both the fundamental understanding of Vps proteins regulation and potential biocontrol applications against plant-parasitic nematodes.