Background Fungal decomposition of wood is considered as a strictly aerobic process. However, recent findings on wood-decaying fungi to produce ethanol from various lignocelluloses under oxygen-depleted conditions lead us to question this. We designed gene expression study of the white rot fungus Phlebia radiata (isolate FBCC0043) by adopting comparative transcriptomics and functional genomics on solid lignocellulose substrates under varying cultivation atmospheric conditions. Results Switch to fermentative conditions was a major regulator for intracellular metabolism and extracellular enzymatic degradation of wood polysaccharides. Changes in the expression profiles of CAZy (carbohydrate-active enzyme) encoding genes upon oxygen depletion, lead into an alternative wood decomposition strategy. Surprisingly, we noticed higher cellulolytic activity under fermentative conditions in comparison to aerobic cultivation. In addition, our results manifest how oxygen depletion affects over 200 genes of fungal primary metabolism including several transcription factors. We present new functions for acetate generating phosphoketolase pathway and its potential regulator, Adr1 transcription factor, in carbon catabolism under oxygen depletion. Conclusions Physiologically resilient wood-decomposing Basidiomycota species P. radiata is capable of thriving under respirative and fermentative conditions utilizing only untreated lignocellulose as carbon source. Hypoxia-response mechanism in the fungus is, however, divergent from the regulation described for Ascomycota fermenting yeasts or animal-pathogenic species of Basidiomycota.

中文翻译：

---

缺氧正在调节丝状白腐菌的酶促木材分解和细胞内碳水化合物代谢。

背景 木材的真菌分解被认为是一个严格的需氧过程。然而，最近关于木材腐烂真菌在缺氧条件下从各种木质纤维素生产乙醇的发现使我们对此提出质疑。我们通过在不同培养大气条件下对固体木质纤维素基质采用比较转录组学和功能基因组学，设计了白腐真菌 Phlebia radiata（分离株 FBCC0043）的基因表达研究。结果转换到发酵条件是木材多糖胞内代谢和胞外酶降解的主要调节剂。CAZy（碳水化合物活性酶）编码基因在氧耗竭时表达谱的变化，导致了另一种木材分解策略。出奇，我们注意到与好氧培养相比，发酵条件下的纤维素分解活性更高。此外，我们的结果表明氧气消耗如何影响 200 多种真菌初级代谢基因，包括几种转录因子。我们提出了乙酸生成磷酸酮醇酶途径及其潜在调节因子 Adr1 转录因子在氧耗竭下碳分解代谢的新功能。结论 具有生理弹性的木材分解担子菌属物种 P. radiata 能够在仅利用未经处理的木质纤维素作为碳源的呼吸和发酵条件下茁壮成长。然而，真菌中的缺氧反应机制与对发酵子囊菌或担子菌的动物病原物种描述的调节不同。