Table_1_Involvement of PaSNF1 in Fungal Development, Sterigmatocystin Biosynthesis, and Lignocellulosic Degradation in the Filamentous Fungus Podospora anserina.xlsx

The sucrose non-fermenting 1/AMP-activated protein kinase (SNF1/AMPK) is a central regulator of carbon metabolism and energy production in the eukaryotes. In this study, the functions of the Podospora anserina SNF1 (PaSNF1) ortholog were investigated. The ΔPaSNF1 mutant displays a delayed development of mycelium and fruiting bodies and fails to form ascospores. The expression of the PaSNF1 gene in the strain providing female organs in a cross is sufficient to ensure fertility, indicating a maternal effect. Results of environmental stress showed that ΔPaSNF1 was hypersensitive to stress, such as osmotic pressure and heat shock, and resistant to fluconazole. Interestingly, the knockout of PaSNF1 significantly promoted sterigmatocystin (ST) synthesis but suppressed cellulase [filter paperase (FPA), endoglucanase (EG), and β-glucosidase (BG)] activity. Further, transcriptome analysis indicated that PaSNF1 made positive regulatory effects on the expression of genes encoding cellulolytic enzymes. These results suggested that PaSNF1 may function in balancing the operation of primary and secondary metabolism. This study suggested that SNF1 was a key regulator concerting vegetative growth, sexual development, and stress tolerance. Our study provided the first genetic evidence that SNF1 was involved in the ST biosynthesis and that it may also be a major actor of lignocellulose degradation in P. anserina.

蔗糖非发酵1/AMP激活蛋白激酶（sucrose non-fermenting 1/AMP-activated protein kinase, SNF1/AMPK）是真核生物碳代谢与能量生成的核心调控因子。本研究针对鹅柄孢壳（Podospora anserina）的SNF1同源基因PaSNF1的功能展开了探究。ΔPaSNF1突变体表现出菌丝体与子实体发育延迟的表型，且无法形成子囊孢子。在杂交实验中，于提供雌性生殖器官的菌株中表达PaSNF1基因即可恢复其育性，这表明该基因存在母性效应。环境胁迫实验结果显示，ΔPaSNF1突变体对渗透压、热激等胁迫表现出超敏感性，且对氟康唑具有抗性。值得注意的是，敲除PaSNF1可显著促进杂色曲霉素（sterigmatocystin, ST）的合成，但会抑制纤维素酶[滤纸酶（FPA）、内切葡聚糖酶（EG）与β-葡萄糖苷酶（BG）]的活性。进一步的转录组分析表明，PaSNF1对编码纤维素降解酶的基因表达具有正向调控作用。上述结果提示，PaSNF1可能在平衡初生代谢与次生代谢的运转中发挥功能。本研究表明，SNF1是协调营养生长、有性发育与胁迫耐受性的关键调控因子。本研究首次提供了遗传证据，证实SNF1参与杂色曲霉素的生物合成，同时提示其可能是鹅柄孢壳中木质纤维素降解的关键作用因子。