The molecular response of the white-rot fungus Dichomitus squalens to wood and non-woody biomass as examined by transcriptome and exoproteome analyses. Dichomitus squalens

The ability to obtain carbon and energy is a major requirement to exist in any environment. For several ascomycete fungi (post-)genomic analyses have shown that species that occupy a large variety of habitats possess a diverse enzymatic machinery, while species with a specific habitat have a more focused enzyme repertoire that is well-adapted to the prevailing substrate. White-rot basidiomycete fungi also live in a specific habitat, as they are found exclusively in wood. In this study we evaluated how well the white-rot fungus Dichomitus squalens has adapted to degrade its natural wood substrate. The transcriptome and exoproteome of D. squalens were analysed after cultivation on two natural substrates, aspen and spruce wood, and two non-woody substrates, wheat bran and cotton seed hulls. D. squalens produced ligninolytic enzymes mainly at the early time point of the wood cultures, indicating the need to degrade lignin to get access to wood polysaccharides. Surprisingly, the response of the fungus to the non-woody polysaccharides was nearly as good match to the substrate composition as observed for the wood polysaccharides. This indicates that D. squalens has preserved its ability to efficiently degrade plant polysaccharides not present in its natural habitat. Overall design: This study compares the gene expression of D. squalens growing on different plant biomass at two different time points. The culture medium was supplemented with spruce wood (Picea abies) sawdust, aspen wood (Populus tremula) sawdust, powdered wheat bran or powdered cotton seed hulls respectively. Samples were taken after 9 and 16 days of culture.

获取碳源与能量的能力是所有生物在任一环境中生存的核心必备条件。针对多种子囊菌（Ascomycete fungi）的（后）基因组分析表明，栖息于多样生境的物种拥有多样化的酶促系统，而生境特化的物种则具备更聚焦的酶谱，可很好地适配其优势底物。白腐担子菌（White-rot basidiomycete fungi）仅生存于木材环境中，同样属于生境特化类群。本研究旨在评估白腐真菌粗毛盖孔菌（Dichomitus squalens）对其天然木材底物的降解适配能力。本研究分别以两种天然木质底物——山杨木与云杉木，以及两种非木质底物——麦麸与棉籽壳进行培养，随后对粗毛盖孔菌的转录组（Transcriptome）与分泌蛋白组（Exoproteome）开展分析。实验结果显示，该真菌在木质底物培养的早期阶段主要分泌木质素降解酶，这表明其需先降解木质素，才能获取木材中的多糖组分。令人意外的是，该真菌对非木质多糖的响应模式，几乎可与木质多糖底物的组分实现同等程度的精准匹配。这一结果表明，粗毛盖孔菌仍保留了高效降解其天然生境中不存在的植物多糖的能力。实验整体设计：本研究对比了粗毛盖孔菌在两种不同时间点、于不同植物生物质上生长时的基因表达情况。培养基分别添加云杉（Picea abies）木屑、山杨（Populus tremula）木屑、麦麸粉或棉籽壳粉。分别在培养第9天与第16天采集样本。