MAPK pathway components AoSho1 and AoOpy2 regulate growth, sporulation, osmoregulation, and pathogenicity in...

Arthrobotrys oligospora, a widely distributed nematode-trapping fungus, utilises adhesive mycelial nets (traps) to capture nematodes. As key components of the MAPK cascade, Sho1 and Opy2 are critical in the fungal stress response. This study examined the roles of homologous Sho1 (AoSho1) and Opy2 (AoOpy2) through gene knockout, phenotypic analysis, and multi-omics approaches. The results revealed that knockout of Aosho1 and Aoopy2 led to reduced mycelial growth, a significant decrease in spore production, trap formation, and nematode predation capacity. Furthermore, deletion of Aosho1 and Aoopy2 increased autophagic activity and heightened sensitivity to osmotic stress. Transcriptome analysis indicated that AoOpy2 functions as a multifaceted regulator in fungal growth, development, and environmental adaptation. Metabolomics data also suggested that AoSho1 and AoOpy2 are involved in several metabolic pathways. In conclusion, AoSho1 and AoOpy2 are essential for mycelial growth, osmoregulation, and the pathogenicity of A. oligospora. This study lays the groundwork for understanding the roles and potential mechanisms of the MAPK signalling pathway in the development and pathogenicity of nematode-trapping fungi.