Single-cell transcriptome sequencing of rumen ciliates provides insight into their molecular adaptations to the anaerobic and carbohydrate-rich rumen microenvironment
Single-cell transcriptome sequencing of rumen ciliates provides insight into their molecular adaptations to the anaerobic and carbohydrate-rich rumen microenvironment
复制标题
瘤胃纤毛虫的单细胞转录组测序可深入了解它们对厌氧和富含碳水化合物的瘤胃微环境的分子适应
DOI：
10.1016/j.ympev.2019.106687
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发表时间：
2020-02-01
影响因子：
4.1
通讯作者：
Xiong, Jie
中科院分区：
文献类型：
--
作者：
Feng, Jin-Mei;Jiang, Chuan-Qi;Xiong, Jie
瘤胃纤毛虫是一种专门存在于厌氧、富含碳水化合物的瘤胃微环境中的纤毛虫。然而，纤毛虫的生理和行为适应瘤胃微环境的分子和机制基础是不确定的。我们使用单细胞转录组测序，探讨适应性进化的三个瘤胃纤毛虫：两个entodiniomorphids，Entodinium furca和Diplodinium dentatum;和一个vestibuliferid，Isotricha dentatum。我们发现这三个物种都是单系目的成员，在纲Litostomatea，与E。furca和D. dentatum和I. intestinalis in Vestibuliferida.这两种内甲纲动物可能使用产生H-2的线粒体，而前庭纲动物可能使用厌氧线粒体在严格的厌氧条件下生存。此外，碳水化合物活性酶（CAZyme）基因被确定在所有三个物种，包括纤维素酶，半纤维素酶，和果胶酶。这三个物种通过水平基因转移（HGT）消化植物生物量获得原核生物来源的基因的证据包括显著丰富的基因本体类别，如细胞壁大分子分解代谢过程和碳水化合物分解代谢过程，以及鉴定CAZyme和HGT组之间的共同基因。这些结果表明，HGT可能是纤毛虫对瘤胃微环境适应性进化的重要机制。
Rumen ciliates are a specialized group of ciliates exclusively found in the anaerobic, carbohydrate-rich rumen microenvironment. However, the molecular and mechanistic basis of the physiological and behavioral adaptation of ciliates to the rumen microenvironment is undefined. We used single-cell transcriptome sequencing to explore the adaptive evolution of three rumen ciliates: two entodiniomorphids, Entodinium furca and Diplodinium dentatum; and one vestibuliferid, Isotricha intestinalis. We found that all three species are members of monophyletic orders within the class Litostomatea, with E. furca and D. dentatum in Entodiniomorphida and I. intestinalis in Vestibuliferida. The two entodiniomorphids might use H-2-producing mitochondria and the vestibuliferid might use anaerobic mitochondria to survive under strictly anaerobic conditions. Moreover, carbohydrate-active enzyme (CAZyme) genes were identified in all three species, including cellulases, hemicellulases, and pectinases. The evidence that all three species have acquired prokaryote-derived genes by horizontal gene transfer (HGT) to digest plant biomass includes a significant enrichment of gene ontology categories such as cell wall macromolecule catabolic process and carbohydrate catabolic process and the identification of genes in common between CAZyme and HGT groups. These findings suggest that HGT might be an important mechanism in the adaptive evolution of ciliates to the rumen microenvironment.