PDF(Pubmed)
Abstract：
Species differentiation and the appearance of novel diversity on Earth is a major issue to understand the past and future of microbial evolution. Herein, we propose the analysis of a singular evolutive example, the case of microorganisms carrying out the process of anammox (anaerobic ammonium oxidation). Anammox represents a singular physiology active on Earth from ancient times and, at present, this group is still represented by a relatively limited number of species carrying out a specific metabolism within the Phylum Planctomycetota. The key enzyme on the anammox pathway is hydrazine dehydrogenase (HDH) which has been used as a model in this study. HDH and rRNA (16S subunit) phylogenies are in agreement suggesting a monophyletic origin. The diversity of this singular phylogenetic group is represented by a few enriched bacterial consortia awaiting to be cultured as monospecific taxa. The apparent evolution of the HDH genes in these anammox bacteria is highly related to the diversification of the anammox clades and their genomes as pointed by phylogenomics, their GC content and codon usage profile. This study represents a clear case where bacterial evolution presents a paralleled genome, gene and species diversification through time from a common ancestor; a scenario that most times is masked by a web-like phylogeny and the huge complexity within the prokaryotes. Besides, this contribution suggests that microbial evolution of the anammox bacteria has followed an ordered, vertical diversification through Earth history and will present a potentially similar speciation fate in the future.
摘要：
物种分化和地球上新型多样性的出现是了解微生物进化的过去和未来的主要问题。在这里，我们提出了一个奇异进化例子的分析，微生物进行厌氧氨氧化（厌氧氨氧化）过程的情况。Anammox代表了一种从远古时代开始活跃在地球上的单一生理学，目前,该组仍然由相对有限数量的物种代表，这些物种在毛竹内进行特定的代谢。厌氧氨氧化途径的关键酶是肼脱氢酶（HDH），该酶已被用作本研究的模型。HDH和rRNA（16S亚基）系统发育一致，表明是单系起源。这个独特的系统发育组的多样性由一些富集的细菌聚生体代表，这些细菌聚生体等待作为单特异性分类单元进行培养。这些厌氧氨氧化细菌中HDH基因的明显进化与系统基因组学指出的厌氧氨氧化进化枝及其基因组的多样化高度相关。它们的GC含量和密码子使用谱。这项研究代表了一个明确的案例，即细菌进化呈现出一个平行的基因组，来自共同祖先的基因和物种通过时间的多样化；这种情况大多数时候被网状系统发育和原核生物内部的巨大复杂性所掩盖。此外,这一贡献表明，厌氧氨氧化细菌的微生物进化遵循有序的，通过地球历史的垂直多样化，并将在未来呈现潜在的类似物种形成命运。
