Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada.
Microb Genom. 2024 Nov;10(11). doi: 10.1099/mgen.0.001324.
is a genus of organohalide-respiring bacteria that is recognized for its fastidious growth using reductive dehalogenases (RDases). In the SC05 culture, however, a population also mineralizes dichloromethane (DCM) produced by chloroform dechlorination using the cassette, just downstream of its active RDase. A closed genome of this DCM-mineralizing lineage has previously evaded assembly. Here, we present the genomes of two novel strains, each of which was assembled from the metagenome of a distinct subculture from SC05. A pangenomic analysis of the genus, including RDase synteny and phylogenomics, reveals at least five species of based on average nucleotide identity, RDase and core gene synteny, as well as differential functional genes. An integration hotspot is also pinpointed in the genome, in which many recombinase islands have accumulated. This nested recombinase island encodes the active RDase and cassette in both SC05 genomes, indicating the transfer of key functional genes between species of . Horizontal gene transfer between these two novel strains has implications for the evolutionary history within the SC05 subcultures and of the genus as a whole, especially regarding adaptation to anthropogenic chemicals.
是一类利用还原脱卤酶（RDases）进行严格生长的有机卤化物呼吸细菌。然而，在 SC05 培养物中，一个种群也会矿化三氯甲烷（CHCl3）脱氯产生的二氯甲烷（DCM），使用的是 盒，就在其活性 RDase 的下游。该 DCM 矿化谱系的封闭基因组以前一直无法组装。在这里，我们介绍了两个新的 菌株的基因组，每个基因组都是从 SC05 的不同亚培养物的宏基因组中组装而来。对 属的泛基因组分析，包括 RDase 同线性和系统基因组学，表明至少有五种基于平均核苷酸同一性、RDase 和核心基因同线性以及差异功能基因的 种。在 基因组中还精确定位到一个整合热点，其中积累了许多重组酶岛。这个嵌套的重组酶岛在两个 SC05 基因组中都编码了活性 RDase 和 盒，表明关键功能基因在 属的不同种之间发生了转移。这两个新的 菌株之间的水平基因转移对 SC05 亚培养物内部以及整个 属的进化历史具有重要意义，特别是在适应人为化学品方面。
