不同碳源条件下广叶绣球菌转录组分析

Transcriptome analysis of Sparassis latifolia cultivated with different carbon sources

【背景】广叶绣球菌(Sparassis latifolia)是一种名贵的食用菌,其木质纤维素降解的分子机制尚不明确。【目的】了解广叶绣球菌在不同碳源条件下木质纤维素降解相关基因表达动态。【方法】通过转录组测序技术对分别以葡萄糖、纤维素+木质素、纤维素及松木屑为碳源的广叶绣球菌基因表达谱进行分析。以葡萄糖为碳源的样本为对照,分别对不同碳源下广叶绣球菌显著差异表达的基因进行功能分析。【结果】Geneontology(Go)富集分析表明,以葡萄糖为碳源的样本为对照,差异表达基因主要富集在碳水化合物利用的过程,如多糖催化过程、碳水化合物催化过程、碳水化合物代谢过程及多糖代谢过程等。碳水化合物活性酶(Carbohydrate-activeenzymes,CAZymes)功能注释表明,碳源种类主要影响了半纤维素和纤维素降解相关糖苷水解酶家族基因的表达,其中涉及半纤维素降解的相关酶基因上调幅度最大。同时,在纤维素+木质素、松木屑为碳源的处理组中一些转录因子基因上调表达显著。【结论】不同碳源显著影响了广叶绣球菌基因表达谱,这种对碳源的适应也可能反映了广叶绣球菌攻击植物细胞壁的机制,研究结果为深入了解广叶绣球菌木质纤维素降解的分子机理和相关功能基因提供了一些参考。

[Background] Sparassis latifolia is a valuable edible fungi.However,lignocellulose degradation mechanism is poorly understood.[Objective] To understand expression profiles of lignocellulose degradation associated genes cultivated with different carbon sources.[Methods] Based on RNA sequencing,we obtained the whole-genome expression profiles when the mycelia of S.latifolia were cultured with glucose,cellulose,cellulose/lignin and pine sawdust as the carbon source respectively.Using glucose sample as control,functional analysis of differentially expressed genes was carried out.[Results]Gene ontology enrichment analysis showed that,differently expressed genes which compared to glucose as the sole carbon source were mainly involved in polysaccharide catabolic process,carbohydrate catabolic process,polysaccharide metabolic process and carbohydrate metabolic process.Carbohydrate-active enzymes annotation showed that,transcript levels of genes encoding glycoside hydrolases,thought to be important for hydrolytic cleavage of hemicelluloses and cellulose were mainly influenced by the species of carbon source,and in which genes involved in hemicellulose degradation were mostly up-regulated.Several transcription factor genes up-regulated significantly when the carbon source was cellulose/lignin or pine sawdust respectively.[Conclusion] S.latifolia gene expression pattern is influenced substantially by the species of carbon source.Such adaptations to the carbon source may also reflect fundamental mechanisms by which S.latifolia attack plant cell walls.Our findings provide important information in exploring the potential genes responsible for lignocellulose degradation.