Microbial adaptation to environmental niches can be reproduced by experimental evolution
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ABSTRACT: Experimental evolution is a powerful approach to study how ecological forces shape microbial genotypes and phenotypes, but to date strains were predominantly adapted to conditions specific to laboratory environments. The lactic acid bacterium Lactococcus lactis naturally occurs on plants and in the dairy environment and it is generally believed, that dairy strains originate from the plant niche. Here we investigated the adaptive process from the plant to the dairy niche and show that during the experimental evolution of a L. lactis plant isolate in milk, several mutations are selected that affect amino acid metabolism and transport. Three independently evolved strains were characterized by whole genome re-sequencing, revealing 4 to 28 mutational changes in the individual strains. Two of the adapted strains showed clearly increased acidification rates and yields in milk, and contained three identical point mutations. Transcriptome profiling and extensive phenotyping of the wild-type plant isolate compared to the evolved mutants, and a "natural" dairy isolate confirmed that major physiological changes associated with improved performance in the dairy environment relate to nitrogen metabolism. The deletion of a putative transposable element led to a significant decrease of the mutation rate in two of the adapted strains. These results specify the adaptation of a L. lactis strain isolated from mung bean sprouts to growth in milk and they demonstrate that niche-specific adaptations found in environmental microbes can be reproduced by experimental evolution. Multiple loop design with 12 samples and 16 dual label arrays. Each sample is hybrdized at least on two different arrays and with both dyes.
ORGANISM(S): Lactococcus lactis subsp. lactis
SUBMITTER: Douwe Molenaar
PROVIDER: E-GEOD-20373 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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