Coprinopsis cinerea is a model mushroom-forming basidiomycete which produces basidiospores during sexual reproduction. This fungus is widely used to study fruiting body formation and development. Molecular mechanisms controlling its growth from vegetative mycelium to multicellular mature fruiting body have been studied extensively. However, little is known about the underlying biological processes during germ tube outgrowth or the transition from basidiospores to multinucleate hyphae. To better understand sexual spore germination in fungi, here we examined the time-dependent cellular events at resting, germinating and fully germinated basidiospores of C. cinerea by genome-wide transcriptional and post-transcriptional analyses and by carbohydrate composition analysis. Our results revealed a high demand of protein degradation, and biosynthesis of various compounds at the early stage of basidiospore gemination and dynamic changes of carbohydrate metabolism throughout the germination process. Seven microRNA-like RNAs (milRNAs) were identified in the resting basidiospores of C. cinerea, six of which were basidiospore-specific. Glycogen and trehalose were shown to be the carbon sources supporting the initiation of germ tube outgrowth. One basidiospore-specific milRNA, cci-milR-37, was found to be a potential regulator of glycogen metabolic pathways related to vegetative hyphal growth. Our results demonstrated the mRNA and miRNA-mediated regulation on energy production, protein and carbohydrate metabolisms at the early developmental stages of germ tube to form totipotent hyphae. To our knowledge, this is the first study to show the roles of miRNAs in mushroom basidiospore germination and out-growth.

Coprinopsis cinerea是一种模型形成蘑菇的担子菌，在有性生殖过程中产生担子孢子。这种真菌被广泛用于研究子实体的形成和发育。控制其从营养菌丝体到多细胞成熟子实体生长的分子机制已被广泛研究。然而，对于胚管生长或从担子孢子到多核菌丝的转变过程中的潜在生物过程知之甚少。为了更好地了解真菌中的有性孢子萌发，我们在这里检查了C. cinerea 的静息、萌发和完全萌发的担子孢子的时间依赖性细胞事件通过全基因组转录和转录后分析以及碳水化合物组成分析。我们的研究结果表明，在担子孢子萌发的早期阶段对蛋白质降解和各种化合物的生物合成以及整个萌发过程中碳水化合物代谢的动态变化有很高的需求。在C. cinerea的静息担孢子中鉴定出 7 种类似 microRNA 的 RNA (milRNA)，其中六个是担子孢子特异性的。糖原和海藻糖被证明是支持胚管向外生长的碳源。发现一种担子孢子特异性 milRNA，cci-milR-37，是与营养菌丝生长相关的糖原代谢途径的潜在调节剂。我们的研究结果表明，在胚管形成全能菌丝的早期发育阶段，mRNA 和 miRNA 介导的能量产生、蛋白质和碳水化合物代谢调节。据我们所知，这是第一项显示 miRNA 在蘑菇担孢子萌发和向外生长中的作用的研究。