Phospholipase C (AoPLC2) regulates mycelial development, trap morphogenesis, and pathogenicity of the nematode-trapping fungus Arthrobotrys oligospora

Aims Phospholipase C (PLC) is a hydrolase involved in signal transduction in eukaryotic cells. This study aimed to understand the function of PLC in the nematode-trapping fungus Arthrobotrys oligospora. Methods and Results Orthologous PLC (AoPLC2) of A. oligospora was functionally analysed using gene disruption and multi-phenotypic analysis. Disrupting Aoplc2 caused a deformation of partial hyphal cells (about 10%) and conidia (about 50%), decreased the number of nuclei in both conidia and hyphal cells, and increased the accumulation of lipid droplets. Meanwhile, the sporulation-related genes fluG and abaA were downregulated in Delta Aoplc2 mutants than in the wild-type strain. Moreover, Delta Aoplc2 mutants were more sensitive to osmotic stressors. Importantly, the number of traps, electron-dense bodies in traps, and nematicidal activity of Delta Aoplc2 mutants were reduced, and the shape of the traps was deformed. In addition, AoPLC2 was involved in the biosynthesis of secondary metabolites in A. oligospora. Conclusions AoPLC2 plays an important role in the development of hyphae, spores, and cell nuclei, responses to stress, formation of traps, and predation of nematodes in A. oligospora. Significance and Impact of study This study reveals the various functions of phospholipase C and elucidates the regulation of trap morphogenesis in nematode-trapping fungi.