Terebieniec Agata, Müller Astrid, Chroumpi Tania, Li Jiajia, Peng Mao, Mäkelä Miia R, de Vries Ronald P
Microb Physiol. 2025 Aug 1:1-19. doi: 10.1159/000547578.
D-Xylose and L-arabinose are major components of plant biomass and as such also important carbon sources for most fungi and attractive compounds for biotechnology. Most fungi use the pentose catabolic pathway to convert these sugars through several redox reactions. One of the steps in this pathway is the conversion of L-xylulose to xylitol, catalyzed by L-xylulose reductase (LXR). Genetic studies in Aspergillus niger revealed the involvement of two LXR-encoding genes, lxrA and lxrB. In this study, we compared the corresponding enzymes, LxrA and LxrB, with respect to substrate specificity and kinetic properties, which revealed significant differences between them. Evaluation of these genes and their homologs from A. niger and selected other fungi revealed high diversity at the level of number of homologs per species, phylogenetic relationship and expression profiles, suggesting species-specific adaptations in fungal sugar metabolism. This study therefore not only provides more detailed insights into an ecologically and biotechnologically important fungal metabolic pathway, but also demonstrates the high diversity of sugar metabolism in fungi. This is especially relevant when knowledge from one species is transferred to another, e.g., for the engineering of fungal cell factories.
D-木糖和L-阿拉伯糖是植物生物质的主要成分，因此也是大多数真菌的重要碳源以及生物技术领域具有吸引力的化合物。大多数真菌利用戊糖分解代谢途径通过几个氧化还原反应来转化这些糖类。该途径中的一个步骤是由L-木酮糖还原酶（LXR）催化L-木酮糖转化为木糖醇。对黑曲霉的遗传学研究揭示了两个编码LXR的基因lxrA和lxrB的参与情况。在本研究中，我们比较了相应的酶LxrA和LxrB的底物特异性和动力学特性，结果显示它们之间存在显著差异。对来自黑曲霉和其他选定真菌的这些基因及其同源物的评估表明，在每个物种的同源物数量、系统发育关系和表达谱水平上存在高度多样性，这表明真菌糖代谢存在物种特异性适应性。因此，本研究不仅为一个在生态和生物技术方面具有重要意义的真菌代谢途径提供了更详细的见解，还证明了真菌糖代谢的高度多样性。当将一个物种的知识转移到另一个物种时，例如用于真菌细胞工厂的工程设计时，这一点尤为重要。
