Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China.
Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, PR China.
Microb Genom. 2021 Dec;7(12). doi: 10.1099/mgen.0.000711.
spp. are important enteric pathogens in a wide range of vertebrates including humans. Previous comparative analysis revealed conservation in genome composition, gene content, and gene organization among spp., with a progressive reductive evolution in metabolic pathways and invasion-related proteins. In this study, we sequenced the genome of zoonotic pathogen and conducted a comparative genomic analysis. While most intestinal species have similar genomic characteristics and almost complete genome synteny, fewer protein-coding genes and some sequence inversions and translocations were found in the genome. The genome exhibits much higher GC content (39.6 %) than other species (24.3-32.9 %), especially at the third codon position (GC3) of protein-coding genes. Thus, has a different codon usage, which increases the use of less energy costly amino acids (Gly and Ala) encoded by GC-rich codons. While the tRNA usage is conserved among species, consistent with its higher GC content, uses a unique tRNA for GTG for valine instead of GTA in other species. Both mutational pressures and natural selection are associated with the evolution of the codon usage in spp., while natural selection seems to drive the codon usage in . Other unique features of the genome include the loss of the entire traditional and alternative electron transport systems and several invasion-related proteins. Thus, the preference for the use of some less energy costly amino acids in may lead to a more harmonious parasite-host interaction, and the strengthened host-adaptation is reflected by the further reductive evolution of metabolism and host invasion-related proteins.
spp. 是广泛存在于脊椎动物（包括人类）中的重要肠道病原体。先前的比较分析表明， spp. 在基因组组成、基因内容和基因组织方面具有保守性，而代谢途径和入侵相关蛋白则呈现出逐渐的简化进化。在本研究中，我们对人畜共患病病原体 spp. 进行了基因组测序，并进行了比较基因组分析。虽然大多数肠道 spp. 具有相似的基因组特征和几乎完整的基因组同线性，但在 基因组中发现了较少的编码蛋白基因和一些序列倒位和易位。 基因组的 GC 含量（39.6%）明显高于其他 spp.（24.3-32.9%），尤其是在编码蛋白基因的第三密码子位置（GC3）。因此， 具有不同的密码子使用偏好，增加了由 GC 丰富密码子编码的低能耗氨基酸（甘氨酸和丙氨酸）的使用。尽管 spp. 中的 tRNA 使用是保守的，但与其较高的 GC 含量一致， 用独特的 tRNA GTG 替代了其他 spp. 中编码缬氨酸的 tRNA GTA。突变压力和自然选择都与 spp. 中密码子使用的进化有关，而自然选择似乎驱动了 中的密码子使用。 基因组的其他独特特征包括整个传统和替代电子传递系统以及几种入侵相关蛋白的缺失。因此， 中对一些低能耗氨基酸的偏好可能导致寄生虫与宿主之间更和谐的相互作用，而代谢和宿主入侵相关蛋白的进一步简化进化则反映了对宿主适应的加强。
