Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2R3, Canada.
CEGIIR, University of Alberta, Edmonton, AB T6G 2E1, Canada.
FEMS Microbiol Rev. 2017 Aug 1;41(Supp_1):S27-S48. doi: 10.1093/femsre/fux030.
Lactobacillus species are found in nutrient-rich habitats associated with food, feed, plants, animals and humans. Due to their economic importance, the metabolism, genetics and phylogeny of lactobacilli have been extensively studied. However, past research primarily examined lactobacilli in experimental settings abstracted from any natural history, and the ecological context in which these bacteria exist and evolve has received less attention. In this review, we synthesize phylogenetic, genomic and metabolic metadata of the Lactobacillus genus with findings from fine-scale phylogenetic and functional analyses of representative species to elucidate the evolution and natural history of its members. The available evidence indicates a high level of niche conservatism within the well-supported phylogenetic groups within the genus, with lifestyles ranging from free-living to strictly symbiotic. The findings are consistent with a model in which host-adapted Lactobacillus lineages evolved from free-living ancestors, with present-day species displaying substantial variations in terms of the reliance on environmental niches and the degree of host specificity. This model can provide a framework for the elucidation of the natural and evolutionary history of Lactobacillus species and valuable information to improve the use of this important genus in industrial and therapeutic applications.
乳杆菌属存在于与食物、饲料、植物、动物和人类相关的营养丰富的栖息地中。由于其经济重要性，乳杆菌的代谢、遗传和系统发育已得到广泛研究。然而，过去的研究主要集中在从任何自然历史中抽象出来的实验环境中研究乳杆菌，而这些细菌存在和进化的生态背景则受到较少关注。在这篇综述中，我们综合了乳杆菌属的系统发育、基因组和代谢元数据，以及对代表性物种进行的精细系统发育和功能分析的结果，以阐明其成员的进化和自然历史。现有证据表明，在该属中得到充分支持的系统发育群内，生态位保守性很高，生活方式从自由生活到严格共生不等。这一发现与以下模型一致，即适应宿主的乳杆菌谱系从自由生活的祖先进化而来，目前的物种在对环境生态位的依赖程度和宿主特异性程度上表现出很大的差异。该模型可以为阐明乳杆菌属的自然和进化历史提供框架，并为改善该重要属在工业和治疗应用中的利用提供有价值的信息。
