Abstract

The ability of many bacteria to adapt to diverse environmental conditions is well known. Recent research has linked the process of bacterial adaptation to a niche to changes in the genome content and size, showing that many bacterial genomes reflect the constraints imposed by their habitat. However, some highly versatile bacteria are found in diverse niches that almost share nothing in common. Lactobacillus plantarum is a lactic acid bacterium that is found in a large variety of niches. With the aim of unravelling the link between genome evolution and ecological versatility of L. plantarum, we analysed the genomes of 54 L. plantarum strains isolated from different environments. Phylogenomic analyses coupled with the study of genetic functional divergence and gene-trait matching analysis revealed a mixed distribution of the strains, which was uncoupled from their environmental origin. Our findings demonstrate the high complexity of L. plantarum evolution, revealing the absence of specific genomic signatures marking adaptations of this species towards the diverse habitats it is associated with. This suggests fundamentally similar and parallel trends of genome evolution in L. plantarum, which occur in a manner that is apparently uncoupled from ecological constraint and reflects the nomadic lifestyle of this species.