Peng Mao, Khosravi Claire, Lubbers Ronnie J M, Kun Roland S, Aguilar Pontes Maria Victoria, Battaglia Evy, Chen Cindy, Dalhuijsen Sacha, Daly Paul, Lipzen Anna, Ng Vivian, Yan Juying, Wang Mei, Visser Jaap, Grigoriev Igor V, Mäkelä Miia R, de Vries Ronald P
Fungal Physiology, Westerdijk Fungal Biodiversity Institute, & Fungal Molecular Physiology, Utrecht University, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands.
USA Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA 94720, United States.
Cell Surf. 2021 Mar 3;7:100050. doi: 10.1016/j.tcsw.2021.100050. eCollection 2021 Dec.
Carbon catabolite repression enables fungi to utilize the most favourable carbon source in the environment, and is mediated by a key regulator, CreA, in most fungi. CreA-mediated regulation has mainly been studied at high monosaccharide concentrations, an uncommon situation in most natural biotopes. In nature, many fungi rely on plant biomass as their major carbon source by producing enzymes to degrade plant cell wall polysaccharides into metabolizable sugars. To determine the role of CreA when fungi grow in more natural conditions and in particular with respect to degradation and conversion of plant cell walls, we compared transcriptomes of a deletion and reference strain of the ascomycete during growth on sugar beet pulp and wheat bran. Transcriptomics, extracellular sugar concentrations and growth profiling of on a variety of carbon sources, revealed that also under conditions with low concentrations of free monosaccharides, CreA has a major effect on gene expression in a strong time and substrate composition dependent manner. In addition, we compared the CreA regulon from five fungi during their growth on crude plant biomass or cellulose. It showed that CreA commonly regulated genes related to carbon metabolism, sugar transport and plant cell wall degrading enzymes across different species. We therefore conclude that CreA has a crucial role for fungi also in adapting to low sugar concentrations as occurring in their natural biotopes, which is supported by the presence of CreA orthologs in nearly all fungi.
碳分解代谢物阻遏使真菌能够利用环境中最有利的碳源，并且在大多数真菌中由关键调节因子CreA介导。CreA介导的调控主要是在高单糖浓度下进行研究的，而在大多数自然生物群落中这种情况并不常见。在自然界中，许多真菌通过产生酶将植物细胞壁多糖降解为可代谢的糖，从而依赖植物生物质作为其主要碳源。为了确定CreA在真菌于更自然条件下生长时的作用，特别是在植物细胞壁的降解和转化方面的作用，我们比较了子囊菌的缺失菌株和参考菌株在甜菜粕和麦麸上生长期间的转录组。对多种碳源上的转录组学、细胞外糖浓度和生长情况进行分析，结果表明，即使在游离单糖浓度较低的条件下，CreA也会以强烈的时间和底物组成依赖性方式对基因表达产生重大影响。此外，我们比较了五种真菌在粗植物生物质或纤维素上生长时的CreA调控子。结果显示，CreA在不同物种中通常调控与碳代谢、糖转运和植物细胞壁降解酶相关的基因。因此，我们得出结论，CreA对于真菌适应其自然生物群落中出现的低糖浓度也起着关键作用，几乎所有真菌中都存在CreA直系同源物这一事实也支持了这一点。
