Klinische Forschergruppe, Klinik für Pädiatrische Pneumologie, Allergologie und Neonatologie, Medizinische Hochschule Hannover, Hannover D-30625, Germany.
BMC Genomics. 2013 Jun 22;14:416. doi: 10.1186/1471-2164-14-416.
Adaptation of Pseudomonas aeruginosa to different living conditions is accompanied by microevolution resulting in genomic diversity between strains of the same clonal lineage. In order to detect the impact of colonized habitats on P. aeruginosa microevolution we determined the genomic diversity between the highly virulent cystic fibrosis (CF) isolate CHA and two temporally and geographically unrelated clonal variants. The outcome was compared with the intraclonal genome diversity between three more closely related isolates of another clonal complex.
The three clone CHA isolates differed in their core genome in several dozen strain specific nucleotide exchanges and small deletions from each other. Loss of function mutations and non-conservative amino acid replacements affected several habitat- and lifestyle-associated traits, for example, the key regulator GacS of the switch between acute and chronic disease phenotypes was disrupted in strain CHA. Intraclonal genome diversity manifested in an individual composition of the respective accessory genome whereby the highest number of accessory DNA elements was observed for isolate PT22 from a polluted aquatic habitat. Little intraclonal diversity was observed between three spatiotemporally related outbreak isolates of clone TB. Although phenotypically different, only a few individual SNPs and deletions were detected in the clone TB isolates. Their accessory genome mainly differed in prophage-like DNA elements taken up by one of the strains.
The higher geographical and temporal distance of the clone CHA isolates was associated with an increased intraclonal genome diversity compared to the more closely related clone TB isolates derived from a common source demonstrating the impact of habitat adaptation on the microevolution of P. aeruginosa. However, even short-term habitat differentiation can cause major phenotypic diversification driven by single genomic variation events and uptake of phage DNA.
铜绿假单胞菌适应不同的生活条件伴随着微进化，导致同一克隆谱系的菌株之间存在基因组多样性。为了检测定植栖息地对铜绿假单胞菌微进化的影响，我们测定了高毒力囊性纤维化（CF）分离株 CHA 与两个时间和地理上不相关的克隆变体之间的基因组多样性。结果与另一个克隆复合体的三个更密切相关的分离株之间的种内基因组多样性进行了比较。
三个克隆 CHA 分离株在其核心基因组中彼此之间有几十处菌株特异性核苷酸交换和小缺失。功能丧失突变和非保守氨基酸取代影响了几个与栖息地和生活方式相关的特征，例如，急性和慢性疾病表型之间转换的关键调节因子 GacS 在菌株 CHA 中被破坏。种内基因组多样性表现在各自辅助基因组的个体组成中，其中来自污染水生栖息地的分离株 PT22 观察到最多的辅助 DNA 元件。克隆 TB 的三个时空相关暴发分离株之间观察到的种内多样性很少。尽管表型不同，但在克隆 TB 分离株中仅检测到少数个别 SNP 和缺失。它们的辅助基因组主要在一个菌株中摄取的类似噬菌体的 DNA 元件上有所不同。
与更密切相关的源自同一来源的克隆 TB 分离株相比，克隆 CHA 分离株的地理和时间距离更远，与种内基因组多样性增加相关，表明栖息地适应对铜绿假单胞菌微进化的影响。然而，即使是短期的栖息地分化也可以导致主要的表型多样化，这是由单个基因组变异事件和噬菌体 DNA 的摄取驱动的。
