Host-Microbe Interactomics Group, Animal Sciences Department, Wageningen University, Wageningen, Netherlands.
Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.
Microb Genom. 2023 Apr;9(4). doi: 10.1099/mgen.0.000992.
colonizes the upper respiratory tract of healthy pigs at high abundance but can also cause opportunistic respiratory and systemic disease. Disease-associated reference strains are well studied, but less is known about commensal lineages. It is not known what mechanisms enable some lineages to cause disease while others persist as commensal colonizers, or to what extent gene expression in disease-associated and commensal lineages diverge. In this study we compared the transcriptomes of 21 . strains grown in active porcine serum and Todd-Hewitt yeast broth. These strains included both commensal and pathogenic strains, including several strains of sequence type (ST) 1, which is responsible for most cases of human disease and is considered to be the most pathogenic lineage. We sampled the strains during their exponential growth phase and mapped RNA sequencing reads to the corresponding strain genomes. We found that the transcriptomes of pathogenic and commensal strains with large genomic divergence were unexpectedly conserved when grown in active porcine serum, but that regulation and expression of key pathways varied. Notably, we observed strong variation of expression across media of genes involved in capsule production in pathogens, and of the agmatine deiminase system in commensals. ST1 strains displayed large differences in gene expression between the two media compared to strains from other clades. Their capacity to regulate gene expression across different environmental conditions may be key to their success as zoonotic pathogens.
定植在上呼吸道的健康猪数量多，但也可引起机会性呼吸道和全身疾病。与疾病相关的参考株研究得很好，但对共生谱系知之甚少。不知道是什么机制使一些谱系能够引起疾病，而另一些谱系则作为共生定植体持续存在，或者疾病相关和共生谱系中的基因表达差异有多大。在这项研究中，我们比较了 21 株在活性猪血清和 Todd-Hewitt 酵母肉汤中生长的 菌株的转录组。这些菌株包括共生和致病菌株，包括几个序列型（ST）1 的菌株，该型负责大多数人类疾病病例，被认为是最具致病性的 谱系。我们在菌株的指数生长期取样，并将 RNA 测序读取映射到相应的菌株基因组。我们发现，当在活性猪血清中生长时，具有大基因组差异的致病性和共生菌株的转录组出人意料地保守，但关键途径的调节和表达存在差异。值得注意的是，我们观察到在病原体中参与荚膜产生的基因以及共生体中的胍丁胺脱氨酶系统的基因在不同培养基中的表达存在强烈的变化。与来自其他进化枝的菌株相比，ST1 菌株在两种培养基之间的基因表达存在很大差异。它们在不同环境条件下调节基因表达的能力可能是它们作为人畜共患病病原体成功的关键。
