State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning, People's Republic of China
State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning, People's Republic of China.
Appl Environ Microbiol. 2019 Nov 27;85(24). doi: 10.1128/AEM.01226-19. Print 2019 Dec 15.
Transcriptional regulation of cellulolytic and xylolytic genes in ascomycete fungi is controlled by specific carbon sources in different external environments. Here, comparative transcriptomic analyses of grown on wheat bran (WB), WB plus rice straw (WR), or WB plus Avicel (WA) as the sole carbon source under solid-state fermentation (SSF) revealed that most of the differentially expressed genes (DEGs) were involved in metabolism, specifically, carbohydrate metabolism. Of the DEGs, the basic core carbohydrate-active enzyme-encoding genes which responded to the plant biomass resources were identified in , and their transcriptional levels changed to various extents depending on the different carbon sources. Moreover, this study found that three deletion mutants of genes encoding putative transcription factors showed significant alterations in filter paper cellulase production compared with that of a parental strain with a deletion of (Δ strain) when grown on WR under SSF. Importantly, the Δ mutant (with a deletion of , also called ) displayed 46.1 to 183.2% more cellulase and xylanase production than a Δ mutant after 2 days of growth on WR. RNA sequencing and quantitative reverse transcription-PCR revealed that dynamically regulated the expression of major cellulase and xylanase genes under SSF. PoxAtf1 bound to the promoter regions of the key cellulase and xylanase genes This study provides novel insights into the regulatory mechanism of fungal cellulase and xylanase gene expression under SSF. The transition to a more environmentally friendly economy encourages studies involving the high-value-added utilization of lignocellulosic biomass. Solid-state fermentation (SSF), that simulates the natural habitat of soil microorganisms, is used for a variety of applications such as biomass biorefinery. Prior to the current study, our understanding of genome-wide gene expression and of the regulation of gene expression of lignocellulose-degrading enzymes in ascomycete fungi during SSF was limited. Here, we employed RNA sequencing and genetic analyses to investigate transcriptomes of strain EU2101 cultured on medium containing different carbon sources and to identify and characterize transcription factors for regulating the expression of cellulase and xylanase genes during SSF. The results generated will provide novel insights into genetic engineering of filamentous fungi to further increase enzyme production.
在不同的外部环境中，丝状真菌的细胞裂解和木裂解基因的转录调控受特定碳源的控制。在这里，通过比较转录组分析，在固态发酵（SSF）下，以小麦麸（WB）、WB 加稻草（WR）或 WB 加 Avicel（WA）作为唯一碳源生长的 ，发现大多数差异表达基因（DEGs）参与代谢，特别是碳水化合物代谢。在 DEGs 中，鉴定了对植物生物质资源有反应的基本核心碳水化合物活性酶编码基因，其转录水平根据不同的碳源而发生不同程度的变化。此外，本研究发现，在 SSF 下生长于 WR 时，与具有 （Δ 株）缺失的亲本 株相比，三个编码假定转录因子的基因缺失突变体在滤纸纤维素酶产生方面表现出显著变化。重要的是，与 Δ 突变体（缺失 ）相比，在 WR 上生长 2 天后，Δ 突变体（缺失 ，也称为 ）的纤维素酶和木聚糖酶产量增加了 46.1%至 183.2%。RNA 测序和定量逆转录-PCR 显示，在 SSF 下， 动态调节主要纤维素酶和木聚糖酶基因的表达。PoxAtf1 结合到关键纤维素酶和木聚糖酶基因的启动子区域 本研究为 SSF 下真菌纤维素酶和木聚糖酶基因表达的调控机制提供了新的见解。向更环保的经济的转变鼓励了涉及木质纤维素生物质高附加值利用的研究。固态发酵（SSF）模拟了土壤微生物的自然栖息地，用于各种应用，如生物质生物炼制。在本研究之前，我们对丝状真菌在 SSF 过程中基因组范围内基因表达和木质纤维素降解酶基因表达的调控的理解是有限的。在这里，我们采用 RNA 测序和遗传分析来研究 菌株 EU2101 在含有不同碳源的培养基中培养的转录组，并鉴定和表征转录因子，以调节 SSF 过程中纤维素酶和木聚糖酶基因的表达。所产生的结果将为丝状真菌的基因工程提供新的见解，以进一步提高酶的产量。
