Farrell Anne A, Nesbø Camilla L, Zhaxybayeva Olga
Department of Biological Sciences, Dartmouth College, Hanover, NH, USA.
Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada.
Genome Biol Evol. 2025 Jan 6;17(1). doi: 10.1093/gbe/evae277.
Evolutionary events leading to organismal preference for a specific growth temperature, as well as genes whose products are needed for a proper function at that temperature, are poorly understood. Using 64 bacteria from phylum Thermotogota as a model system, we examined how optimal growth temperature changed throughout Thermotogota history. We inferred that Thermotogota's last common ancestor was a thermophile and that some Thermotogota evolved the mesophilic and hyperthermophilic lifestyles secondarily. By modeling gain and loss of genes throughout Thermotogota history and by reconstructing their phylogenies, we demonstrated that adaptations to lower and higher growth temperature involve both the acquisition of necessary genes and loss of unnecessary genes. Via a pangenome-wide association study, we correlated presence/absence of 68 genes with specific optimal growth temperature intervals. While some of these genes are poorly characterized, most are involved in metabolism of amino acids, nucleotides, carbohydrates, and lipids, as well as in signal transduction and regulation of transcription. Most of the 68 genes have a history of horizontal gene transfer with other bacteria and archaea that often grow at similar temperatures, suggesting that parallel acquisitions of genes likely promote independent adaptations of different Thermotogota species to specific growth temperatures.
导致生物体偏好特定生长温度的进化事件，以及在该温度下正常功能所需的基因产物，目前还知之甚少。我们以64种栖热袍菌门细菌作为模型系统，研究了最佳生长温度在整个栖热袍菌门历史中是如何变化的。我们推断，栖热袍菌门的最后一个共同祖先是嗜热菌，并且一些栖热袍菌后来进化出了嗜温和嗜热的生活方式。通过对整个栖热袍菌门历史中的基因得失进行建模，并重建它们的系统发育，我们证明了对较低和较高生长温度的适应既涉及必要基因的获得，也涉及不必要基因的丢失。通过全基因组关联研究，我们将68个基因的有无与特定的最佳生长温度区间相关联。虽然其中一些基因的特征尚不明确，但大多数基因参与氨基酸、核苷酸、碳水化合物和脂质的代谢，以及信号转导和转录调控。这68个基因中的大多数都有与其他通常在相似温度下生长的细菌和古菌进行水平基因转移的历史，这表明基因的平行获得可能促进了不同栖热袍菌物种对特定生长温度的独立适应。
