Phenotypic and genomic diversity of Lactobacillus plantarum.

Lactobacillus plantarum is a ubiquitous micro-organism that is able to colonise several ecological niches, including vegetables, meat, and dairy substrates. In addition, it is applied as a starter culture for food fermentation. Moreover, L. plantarum has been detected in the human gastro-intestinal tract and some strains belonging to this species are marketed as probiotics. In order to elucidate the molecular basis of the high flexibility and versatility of L. plantarum, we performed an extensive phenotypic and genomic diversity analysis. A collection of 185 isolates was assembled, most from diverse fermented foods, and also from the human intestine. The isolates were characterized by evaluating their fermentation profiles on various substrates and their ability to grow in the presence of growth inhibiting compounds. Subsequently, a cluster analysis was conducted based on phenotypic abilities and about ten different groups could be distinguished. A set of 24 strains representing these distinct phenotypic groups were selected and their genomic variation was studied by hybridizing chromosomal DNA to oligonucleotide microarrays based on the complete genome sequence of L. plantarum WCFS1, as described previously (1). Hybridization profiles were used to categorize the gene content and duplications, and the identification of regions of sequence variability in the different strains. The results provide a detailed view on genomic diversity of L. plantarum and examples of the valorization of these data by gene-trait matching for functional annotation will be presented.