Genome of an Endosymbiont Coupling N2 Fixation to Cellulolysis Within Protist Cells in Termite Gut
Genome of an Endosymbiont Coupling N2 Fixation to Cellulolysis Within Protist Cells in Termite Gut
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DOI：
10.1126/science.1165578
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发表时间：
2008-11-14
期刊：
影响因子：
56.9
通讯作者：
Ohkuma, Moriya
中科院分区：
文献类型：
--
作者：
Hongoh, Yuichi;Sharma, Vineet K.;Ohkuma, Moriya
白蚁体内有多种共生的肠道微生物，其中大多数是不可培养的，它们之间的相互关系也不清楚。在这里，我们提出了完整的基因组序列的未培养的拟杆菌目内共生体的纤维素分解原生生物Pseudotrichonympha grassii，占70%的细菌细胞的白蚁Coptotermes formosanus肠道。染色体（1，114，206个碱基对）的功能注释揭示了其固定双氮和回收推定的宿主氮废物用于生物合成不同氨基酸和辅因子的能力，以及输入葡萄糖和木糖作为能量和碳源的能力。因此，固氮和纤维素分解在原生生物的细胞内相互耦合。这种高度进化的共生系统可能是世界性害虫白蚁以木材为唯一食物的能力的基础。
Termites harbor diverse symbiotic gut microorganisms, the majority of which are as yet uncultivable and their interrelationships unclear. Here, we present the complete genome sequence of the uncultured Bacteroidales endosymbiont of the cellulolytic protist Pseudotrichonympha grassii, which accounts for 70% of the bacterial cells in the gut of the termite Coptotermes formosanus. Functional annotation of the chromosome ( 1,114,206 base pairs) unveiled its ability to fix dinitrogen and recycle putative host nitrogen wastes for biosynthesis of diverse amino acids and cofactors, and import glucose and xylose as energy and carbon sources. Thus, nitrogen fixation and cellulolysis are coupled within the protist's cells. This highly evolved symbiotic system probably underlies the ability of the worldwide pest termites Coptotermes to use wood as their sole food.