Tomazini Atilio, Lal Sadhana, Munir Riffat, Stott Matthew, Henrissat Bernard, Polikarpov Igor, Sparling Richard, Levin David B
a São Carlos Institute of Physics, University of São Paulo, São Carlos 13566-590, São Paulo, Brazil.
b Department of Biosystems Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada.
Can J Microbiol. 2018 Dec;64(12):992-1003. doi: 10.1139/cjm-2018-0336. Epub 2018 Oct 19.
The phylum Chloroflexi is phylogenetically diverse and is a deeply branching lineage of bacteria that express a broad spectrum of physiological and metabolic capabilities. Members of the order Ktedonobacteriales, including the families Ktedonobacteriaceae, Thermosporotrichaceae, and Thermogemmatisporaceae, all have flexible aerobic metabolisms capable of utilizing a wide range of carbohydrates. A number of species within these families are considered cellulolytic and are capable of using cellulose as a sole carbon and energy source. In contrast, Ktedonobacter racemifer, the type strain of the order, does not appear to possess this cellulolytic phenotype. In this study, we confirmed the ability of Thermogemmatispora sp. strain T81 to hydrolyze cellulose, determined the whole-genome sequence of Thermogemmatispora sp. T81, and using comparative bioinformatics analyses, identified genes encoding putative carbohydrate-active enzymes (CAZymes) in the Thermogemmatispora sp. T81, Thermogemmatispora onikobensis, and Ktedonobacter racemifer genomes. Analyses of the Thermogemmatispora sp. T81 genome identified 64 CAZyme gene sequences belonging to 57 glycoside hydrolase families. The genome of Thermogemmatispora sp. T81 encodes 19 genes for putative extracellular CAZymes, similar to the number of putative extracellular CAZymes identified in T. onikobensis (17) and K. racemifer (17), despite K. racemifer not possessing a cellulolytic phenotype. These results suggest that these members of the order Ktedonobacteriales may use a broader range of carbohydrate polymers than currently described.
绿弯菌门在系统发育上具有多样性，是一类具有广泛生理和代谢能力的细菌深层分支谱系。Ktedonobacteriales目成员，包括Ktedonobacteriaceae科、Thermosporotrichaceae科和Thermogemmatisporaceae科，都具有灵活的需氧代谢，能够利用多种碳水化合物。这些科中的一些物种被认为具有纤维素分解能力，能够将纤维素作为唯一的碳源和能源。相比之下，该目的模式菌株消旋Ktedonobacter似乎不具有这种纤维素分解表型。在本研究中，我们证实了热宝石孢菌属菌株T81水解纤维素的能力，测定了热宝石孢菌属T81的全基因组序列，并通过比较生物信息学分析，在热宝石孢菌属T81、奥尼科贝热宝石孢菌和消旋Ktedonobacter的基因组中鉴定了编码假定碳水化合物活性酶（CAZymes）的基因。对热宝石孢菌属T81基因组的分析鉴定出64个属于57个糖苷水解酶家族的CAZyme基因序列。热宝石孢菌属T81的基因组编码19个假定的细胞外CAZymes基因，这与在奥尼科贝热宝石孢菌（17个）和消旋Ktedonobacter（17个）中鉴定出的假定细胞外CAZymes数量相似，尽管消旋Ktedonobacter不具有纤维素分解表型。这些结果表明，Ktedonobacteriales目的这些成员可能利用比目前描述的更广泛的碳水化合物聚合物。
