黄翅大白蚁后肠优势菌大白蚁营发酵菌的全基因组序列分析

Whole-genome analysis of the dominant bacterium Dysgonomonas macrotermitis in the hindgut of Macrotermes barneyi

摘要:

[目的]营发酵单胞菌属Dysgonomonas是黄翅大白蚁后肠的第二优势微生物。前期研究中，我们从黄翅大白蚁后肠分离出一种命名为大白蚁营发酵菌的新菌。为深入了解大白蚁营发酵菌在宿主白蚁体内发挥的作用和功能，有必要解析大白蚁营发酵菌的基因组序列信息。[方法]使用Illumina Miseq测序平台获取该菌的全基因组序列，将其全基因组序列经过注释的基因蛋白质序列提交COG和KEGG数据库进行BLASTp比对分析，确定该菌潜在的重要酶类和代谢途径，并对个别纤维素酶活进行检测。[结果]大白蚁营发酵菌整个基因组大小为4655756 bp，GC含量为38.54%，DDBJ数据库登录号为BBXL01000001–BBXL01000078。生物信息学分析结果表明菌株大白蚁营发酵菌具有多个木质纤维素降解酶基因，且具备完整的木质纤维素降解和乙酸、乳酸生成通路。此外发现该菌株中存在与氮源代谢和抵御病原体相关的基因。[结论]本研究首次解析大白蚁营发酵菌的全基因组序列，了解其基因组基本特征，初步探讨了该菌降解木质纤维素的过程，为细菌协助宿主白蚁降解木质纤维素提供了理论基础，同时为该菌可能参与宿主白蚁氮源代谢和抵御病原体入侵提供了依据。

Abstract:

[Objective] The bacteria of the genus Dysgonomonas are the second dominant microbes in the hindgut of Macrotermes barney. In the previous work, we isolated a novel bacterium from the hindgut of M. barneyi and designated it as Dysgonomonas macrotermitis. To further understand the roles of the bacteria in termite, it is necessary to obtain the genome sequence of D. macrotermitis. [Methods] The whole genome was sequenced by Illumina MiSeq. The protein sequences from the whole genome were annotated and compared with those in the Cluster of Orthologous Groups of proteins (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases by BLASTp. Several potential lignocellulose-degrading enzymes were identified. [Results] The genome sequence is composed of 4655756 bp with G+C content of 38.54%. This whole genome sequencing has been deposited in DDBJ under the accession numbers BBXL01000001 to BBXL01000078. Bioinformatic analysis shows that strain harbored genes encoding important enzymes with potential to degrade lignocellulose. Also, it had a complete cellulose degradation pathway where acetate and lactate were end-products. Genes possibly involved in nitrogen metabolism and defending against pathogens were also identified. [Conclusion] Our findings provide basis for the understanding the roles of hindgut bacteria contributing to termite host lignocellulose degradation.