Characterizing the Role of and in Mycelial and Conidial Development in and Their Role in Secondary Metabolism.

, a widespread nematode-trapping fungus which can produce conidia for asexual reproduction and form trapping devices (traps) to catch nematodes. However, little is known about the sporulation mechanism of . This research characterized the functions and regulatory roles of the upstream spore-producing regulatory genes, and , in . Our analysis showed that and interacted with each other. Meanwhile, the gene was downregulated in the Δ mutant strain, indicating that positively regulates . Loss of the and genes led to shorter hyphae and more septa, and the Δ strain responded to heat and chemical stresses. Surprisingly, the number of nuclei was increased in the mycelia but reduced in the conidia of the Δ and Δ mutants. In addition, after nematode induction, the number and volume of vacuoles were remarkably increased in the Δ and Δ mutant strains. The abundance of metabolites was markedly decreased in the Δ and Δ mutant strains. Collectively, the and genes play critical roles in mycelial development, and they are also involved in vacuole assembly, the stress response, and secondary metabolism. Our study provides distinct insights into the regulatory mechanism of sporulation in nematode-trapping fungi.