Multilayered regulation of autophagy-related protein kinase in Cordyceps militaris

Autophagy is a general eukaryotic mechanism for the degradation and recycling of macromolecules and organelles, whereby the ATG1-kinase complex plays a crucial initiator role. To understand the role of autophagy-related genes in the growth and development of the entomopathogenic parasitoid fungus Cordyceps militaris, we constructed ΔCmATG1 and ΔCmATG13 knockout strains. Compared with the wild type, both knockout strains exhibited severe defects in terms of hyphal morphology, fruiting body formation, conidial production and germination rates, pathogenicity, as well as growth rates under nutritional stress. Moreover, the content of cordycepin, ergosterol, and the levels of phospholipids all exhibited significant decreases, indicating that both ΔCmATG1 and ΔCmATG13 impaired autophagy in the respective knockout strains. Comparative transcriptomic analysis of the wild type and ΔCmATG1 revealed that differentially expressed genes were mainly enriched in phosphoglyceride metabolism, the MAPK signaling pathway, and autophagy-related processes. Taken together, these results demonstrate that the ATG1-kinase complex plays a crucial role in the development of fruiting bodies in C. militaris. This study lays a foundation for further analysis of the molecular mechanisms underlying the role of autophagy in the formation of macrofungal fruiting bodies.