SNF1/AMPK protein kinases play important roles in fungal development and activation of catabolite-repressed genes. In this study, we characterized the role of SNF1 ortholog in Cordyceps militaris (CmSnf1). The vegetative growth of a CmSnf1 deletion mutant was (ΔCmSnf1) reduced by 42.2% with arabinose as a sole carbon source. Most strikingly, the ΔCmSnf1 produced only a few conidia and exhibited delayed conidial germination. We found that CmSnf1 was necessary for mycelium to penetrate the insect cuticle to form the fruiting body on silkworm pupae, consistent with the down-regulation of chitinase- and protease-encoding genes in ΔCmSnf1. However, cordycepin content increased by more than 7 times in culture supernatants. Correspondingly, the relative expression levels of cordycepin gene cluster members were also elevated. In particular, the expression of cns4 associated with cordycepin transfer was up-regulated >10-fold. Furthermore, transcriptional analysis showed that CmSnf1 regulated the expression of genes involved in cell autophagy and oxidative stress tolerance. We speculated that under environmental stress, both the ATG and SNF1 pathways might collaborate to sustain adverse environments. Our study provides an initial framework to probe the diverse function and regulation of CmSnf1 in C. militaris, which will shed more light on the direction of molecular improvement of medicinal fungi.

SNF1/AMPK 蛋白激酶在真菌发育和分解代谢物抑制基因的激活中起重要作用。在这项研究中，我们描述了 SNF1 直系同源物在蛹虫草(CmSnf1) 中的作用。在阿拉伯糖作为唯一碳源的情况下，CmSnf1缺失突变体的营养生长(Δ CmSnf1 ) 减少了 42.2%。最引人注目的是，Δ CmSnf1仅产生少量分生孢子并且表现出延迟的分生孢子萌发。我们发现 CmSnf1 是菌丝体穿透昆虫角质层在蚕蛹上形成子实体所必需的，这与 Δ CmSnf1中几丁质酶和蛋白酶编码基因的下调一致. 然而，培养上清液中虫草素的含量增加了 7 倍以上。相应地，虫草素基因簇成员的相对表达水平也升高。特别是，与虫草素转移相关的cns4的表达上调 > 10 倍。此外，转录分析表明 CmSnf1 调节参与细胞自噬和氧化应激耐受的基因的表达。我们推测，在环境压力下，ATG 和 SNF1 通路可能会合作维持不利环境。我们的研究为探索CmSnf1在C. militaris中的不同功能和调控提供了初步框架，这将为药用真菌的分子改良方向提供更多启示。