Acetylation of Sesquiterpenyl Epoxy-Cyclohexenoids Regulates Fungal Growth, Stress Resistance, Endocytosis, and Pathogenicity of Nematode-Trapping Fungus Arthrobotrys oligospora via Metabolism and Transcription

Sesquiterpenyl epoxy-cyclohexenoids (SECs) that depend on a polyketide synthase-terpenoid synthase (PKS-TPS)pathway are widely distributed in plant pathogenic fungi. However, the biosynthesis and function of the acetylated SECs stillremained cryptic. Here, we identified thatAOL_s00215g273 (273) was responsible for the acetylation of SECs inArthrobotrysoligosporavia the construction of Delta 273, in which the acetylated SECs were absent and major antibacterial nonacetylated SECsaccumulated. Mutant Delta 273 displayed increased trap formation, and nematicidal and antibacterial activities but decreased fungalgrowth and soil colonization. Glutamine, a key precursor for NH3as a trap inducer, was highly accumulated, and biologically activephenylpropanoids and antibiotics were highly enriched in Delta 273. The decreased endocytosis and increased autophagosomes, with themost upregulated genes involved in maintaining DNA and transcriptional stability and pathways related to coronavirus disease andexosome, suggested that lack of 273 might result in increased virus infection and the acetylation of SECs played a key role in fungaldiverse antagonistic ability.