Kameshwar Ayyappa Kumar Sista, Qin Wensheng
Department of Biology, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, P7B 5E1, Canada.
Int J Biol Sci. 2017 Jan 1;13(1):85-99. doi: 10.7150/ijbs.17390. eCollection 2017.
In literature, extensive studies have been conducted on popular wood degrading white rot fungus, about its lignin degrading mechanisms compared to the cellulose and hemicellulose degrading abilities. This study delineates cellulose and hemicellulose degrading mechanisms through large scale metadata analysis of gene expression data (retrieved from NCBI GEO) to understand the common expression patterns of differentially expressed genes when cultured on different growth substrates. Genes encoding glycoside hydrolase classes commonly expressed during breakdown of cellulose such as GH-5,6,7,9,44,45,48 and hemicellulose are GH-2,8,10,11,26,30,43,47 were found to be highly expressed among varied growth conditions including simple customized and complex natural plant biomass growth mediums. Genes encoding carbohydrate esterase class enzymes CE (1,4,8,9,15,16) polysaccharide lyase class enzymes PL-8 and PL-14, and glycosyl transferases classes GT (1,2,4,8,15,20,35,39,48) were differentially expressed in natural plant biomass growth mediums. Based on these results, on natural plant biomass substrates was found to express lignin and hemicellulose degrading enzymes more than cellulolytic enzymes except GH-61 (LPMO) class enzymes, in early stages. It was observed that the fate of transcriptome is significantly affected by the wood substrate provided. We believe, the gene expression findings in this study plays crucial role in developing genetically efficient microbe with effective cellulose and hemicellulose degradation abilities.
在文献中,针对常见的木材降解白腐真菌,已开展了大量研究,涉及与纤维素和半纤维素降解能力相比的木质素降解机制。本研究通过对基因表达数据(从NCBI基因表达综合数据库检索)进行大规模元数据分析,来描绘纤维素和半纤维素的降解机制,以了解在不同生长底物上培养时差异表达基因的共同表达模式。发现在包括简单定制和复杂天然植物生物质生长培养基在内的各种生长条件下,编码纤维素分解过程中常见的糖苷水解酶类(如GH - 5、6、7、9、44、45、48)以及半纤维素降解相关的糖苷水解酶类(如GH - 2、8、10、11、26、30、43、47)的基因高度表达。编码碳水化合物酯酶类(CE - 1、4、8、9、15、16)、多糖裂解酶类(PL - 8和PL - 14)以及糖基转移酶类(GT - 1、2、4、8、15、20、35、39、48)的基因在天然植物生物质生长培养基中差异表达。基于这些结果,发现在天然植物生物质底物上,除了GH - 61(LPMO)类酶外,早期阶段木质素和半纤维素降解酶的表达量比纤维素分解酶更多。观察到转录组的命运受到所提供木材底物的显著影响。我们认为,本研究中的基因表达发现对于开发具有高效纤维素和半纤维素降解能力的基因工程微生物起着关键作用。