Project name: The presence of plasmids in L. lactis IL594 determines changes in host phenotype and expression of chromosomal genes

Description: The L. lactis IL594 strain contains seven plasmids (pIL1 to pIL7) and is the parental strain of the plasmid-free L. lactis IL1403, one of the most studied lactic acid bacteria (LAB) strain. The genetic sequences of pIL1 to pIL7 plasmids have been recently described, however the knowledge of global changes in host phenotype and transcriptome remains poor. In presented study, global phenotypic analyses were combined with transcriptomic studies to evaluate a potential influence of plasmidic genes on overall gene expression in industrially important L. lactis strains. High-throughput screening of phenotypes differences revealed pronounced phenotypic differences in favor of IL594 during the metabolism of seven C-sources, including carbohydrates and β-glucosides. A plasmid-bearing strain presented increased resistance to unfavorable growth conditions, including the presence of heavy metal ions, antibiotics and antimicrobial compounds. Global comparative transcriptomic study of L. lactis strains revealed variation in the expression of over 370 of chromosomal genes caused by plasmids presence. The general trend presented upregulated energy metabolism and biosynthetic genes, differentially expressed regulators, prophages and cell resistance proteins. Our findings suggest that plasmids maintenance leads to significant perturbation in global gene regulation that provide changes in central metabolic pathways and adaptive properties of the IL594 cells.Overall design: The comparison of transcriptomes of the parental Lactococcus lactis IL594 strain containing seven plasmids (pIL1 to pIL7) to the plasmid-free L. lactis IL1403 strain, both grown in the medium with either glucose or cellobiose or galactose as carbon sources and harvested at various growth phases: early exponential (E), mid-exponential (M), transition (T) and stationary (S). For each sample, two technical replicates with dye swapping were performed.

Data type: Transcriptome or Gene expression

Sample scope: Multiisolate

Relevance: Industrial

Last updated: 2022-07-26