title: Strain-Dependent Transcriptome Signatures for Robustness in Lactococcus lactis.
abstract: Recently, we demonstrated that fermentation conditions have a strong impact on subsequent survival of Lactococcus lactis strain MG1363 during heat and oxidative stress, two important parameters during spray drying. Moreover, employment of a transcriptome-phenotype matching approach revealed groups of genes associated with robustness towards heat and/or oxidative stress. To investigate if other strains have similar or distinct transcriptome signatures for robustness, we applied an identical transcriptome-robustness phenotype matching approach on the L. lactis strains IL1403, KF147 and SK11, which have previously been demonstrated to display highly diverse robustness phenotypes. These strains were subjected to an identical fermentation regime as was performed earlier for strain MG1363 and consisted of twelve conditions, varying in the level of salt and/or oxygen, as well as fermentation temperature and pH. In the exponential phase of growth, cells were harvested for transcriptome analysis and assessment of heat and oxidative stress survival phenotypes. The variation in fermentation conditions resulted in differences in heat and oxidative stress survival of up to five 10-log units. Effects of the fermentation conditions on stress survival of the L. lactis strains were typically strain-dependent, although the fermentation conditions had mainly similar effects on the growth characteristics of the different strains. By association of the transcriptomes and robustness phenotypes highly strain-specific transcriptome signatures for robustness towards heat and oxidative stress were identified, indicating that multiple mechanisms exist to increase robustness and, as a consequence, robustness of each strain requires individual optimization. However, a relatively small overlap in the transcriptome responses of the strains was also identified and this generic transcriptome signature included genes previously associated with stress (ctsR and lplL) and novel genes, including nanE and genes encoding transport proteins. The transcript levels of these genes can function as indicators of robustness and could aid in selection of fermentation parameters, potentially resulting in more optimal robustness during spray drying.
authors.affiliation: Kluyver Centre for Genomics of Industrial Fermentation, GA Delft, The Netherlands.|NIZO food research, BA Ede, The Netherlands.|Universiteit van Amsterdam, Swammerdam Institute for Life Sciences, Science Park 904, XH Amsterdam, The Netherlands.
authors.forename: Annereinou R
authors.initials: AR
authors.lastname: Dijkstra
authors.affiliation: Kluyver Centre for Genomics of Industrial Fermentation, GA Delft, The Netherlands.|NIZO food research, BA Ede, The Netherlands.|Centre for Molecular and Biomolecular Informatics, Radboudumc, HB Nijmegen, the Netherlands.
authors.forename: Wynand
authors.initials: W
authors.lastname: Alkema
authors.affiliation: NIZO food research, BA Ede, The Netherlands.
authors.forename: Marjo J C
authors.initials: MJ
authors.lastname: Starrenburg
authors.affiliation: Universiteit van Amsterdam, Swammerdam Institute for Life Sciences, Science Park 904, XH Amsterdam, The Netherlands.
authors.forename: Jeroen
authors.identifier: http://orcid.org/0000-0002-3274-0092
authors.initials: J
authors.lastname: Hugenholtz
authors.affiliation: Kluyver Centre for Genomics of Industrial Fermentation, GA Delft, The Netherlands.|NIZO food research, BA Ede, The Netherlands.|Centre for Molecular and Biomolecular Informatics, Radboudumc, HB Nijmegen, the Netherlands.|TI Food & Nutrition, Nieuwe Kanaal 9A, PA Wageningen, The Netherlands.
authors.forename: Sacha A F T
authors.initials: SA
authors.lastname: van Hijum
authors.affiliation: Kluyver Centre for Genomics of Industrial Fermentation, GA Delft, The Netherlands.|NIZO food research, BA Ede, The Netherlands.|TI Food & Nutrition, Nieuwe Kanaal 9A, PA Wageningen, The Netherlands.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Bron
mesh_terms: D005285:Fermentation; D005516:Food Microbiology; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D016680:Genome, Bacterial; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D013294:Lactococcus lactis / Q000235:genetics* / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress; D010100:Oxygen / Q000737:chemistry; D010641:Phenotype; D012492:Salts / Q000737:chemistry; D059467:Transcriptome
chemical_list: D012492:Salts; D010100:Oxygen