Genetic mechanisms underlying increased microalgal thermotolerance, maximal growth rate, and yield on light following adaptive laboratory evolution
Abstract Background Adaptive laboratory evolution (ALE) is a powerful method for strain optimization towards abiotic stress factors and for identifying adaptation mechanisms. In this study, the green microalga Picochlorum sp. BPE23 was cultured under supra-optimal temperature to force genetic adapta...
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BMC
2022-10-01
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| Series: | BMC Biology |
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| Online Access: | https://doi.org/10.1186/s12915-022-01431-y |
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| author | Robin Barten Dirk-Jan M. van Workum Emma de Bakker Judith Risse Michelle Kleisman Sofia Navalho Sandra Smit Rene H. Wijffels Harm Nijveen Maria J. Barbosa |
| author_facet | Robin Barten Dirk-Jan M. van Workum Emma de Bakker Judith Risse Michelle Kleisman Sofia Navalho Sandra Smit Rene H. Wijffels Harm Nijveen Maria J. Barbosa |
| author_sort | Robin Barten |
| collection | DOAJ |
| description | Abstract Background Adaptive laboratory evolution (ALE) is a powerful method for strain optimization towards abiotic stress factors and for identifying adaptation mechanisms. In this study, the green microalga Picochlorum sp. BPE23 was cultured under supra-optimal temperature to force genetic adaptation. The robustness and adaptive capacity of Picochlorum strains turned them into an emerging model for evolutionary studies on abiotic stressors such as temperature, salinity, and light. Results Mutant strains showed an expanded maximal growth temperature of 44.6 °C, whereas the maximal growth temperature of the wild-type strain was 42 °C. Moreover, at the optimal growth temperature of 38 °C, the biomass yield on light was 22.3% higher, and the maximal growth rate was 70.5% higher than the wild type. Genome sequencing and transcriptome analysis were performed to elucidate the mechanisms behind the improved phenotype. A de novo assembled phased reference genome allowed the identification of 21 genic mutations involved in various processes. Moreover, approximately half of the genome contigs were found to be duplicated or even triplicated in all mutants, suggesting a causal role in adaptation. Conclusions The developed tools and mutant strains provide a strong framework from whereupon Picochlorum sp. BPE23 can be further developed. Moreover, the extensive strain characterization provides evidence of how microalgae evolve to supra-optimal temperature and to photobioreactor growth conditions. With this study, microalgal evolutionary mechanisms were identified by combining ALE with genome sequencing. |
| first_indexed | 2024-04-12T17:52:32Z |
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| id | doaj.art-4817c0b1279c440dada904cabb36061f |
| institution | Directory Open Access Journal |
| issn | 1741-7007 |
| language | English |
| last_indexed | 2024-04-12T17:52:32Z |
| publishDate | 2022-10-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Biology |
| spelling | doaj.art-4817c0b1279c440dada904cabb36061f2022-12-22T03:22:27ZengBMCBMC Biology1741-70072022-10-0120111410.1186/s12915-022-01431-yGenetic mechanisms underlying increased microalgal thermotolerance, maximal growth rate, and yield on light following adaptive laboratory evolutionRobin Barten0Dirk-Jan M. van Workum1Emma de Bakker2Judith Risse3Michelle Kleisman4Sofia Navalho5Sandra Smit6Rene H. Wijffels7Harm Nijveen8Maria J. Barbosa9Bioprocess Engineering & AlgaePARC, Wageningen University and ResearchBioinformatics Group, Wageningen University and ResearchBioprocess Engineering & AlgaePARC, Wageningen University and ResearchBioinformatics Group, Wageningen University and ResearchBioinformatics Group, Wageningen University and ResearchBioprocess Engineering & AlgaePARC, Wageningen University and ResearchBioinformatics Group, Wageningen University and ResearchBioprocess Engineering & AlgaePARC, Wageningen University and ResearchBioinformatics Group, Wageningen University and ResearchBioprocess Engineering & AlgaePARC, Wageningen University and ResearchAbstract Background Adaptive laboratory evolution (ALE) is a powerful method for strain optimization towards abiotic stress factors and for identifying adaptation mechanisms. In this study, the green microalga Picochlorum sp. BPE23 was cultured under supra-optimal temperature to force genetic adaptation. The robustness and adaptive capacity of Picochlorum strains turned them into an emerging model for evolutionary studies on abiotic stressors such as temperature, salinity, and light. Results Mutant strains showed an expanded maximal growth temperature of 44.6 °C, whereas the maximal growth temperature of the wild-type strain was 42 °C. Moreover, at the optimal growth temperature of 38 °C, the biomass yield on light was 22.3% higher, and the maximal growth rate was 70.5% higher than the wild type. Genome sequencing and transcriptome analysis were performed to elucidate the mechanisms behind the improved phenotype. A de novo assembled phased reference genome allowed the identification of 21 genic mutations involved in various processes. Moreover, approximately half of the genome contigs were found to be duplicated or even triplicated in all mutants, suggesting a causal role in adaptation. Conclusions The developed tools and mutant strains provide a strong framework from whereupon Picochlorum sp. BPE23 can be further developed. Moreover, the extensive strain characterization provides evidence of how microalgae evolve to supra-optimal temperature and to photobioreactor growth conditions. With this study, microalgal evolutionary mechanisms were identified by combining ALE with genome sequencing.https://doi.org/10.1186/s12915-022-01431-yAdaptive laboratory evolutionMicroalgaeTemperaturePicochlorumPhotobioreactorGenome assembly |
| spellingShingle | Robin Barten Dirk-Jan M. van Workum Emma de Bakker Judith Risse Michelle Kleisman Sofia Navalho Sandra Smit Rene H. Wijffels Harm Nijveen Maria J. Barbosa Genetic mechanisms underlying increased microalgal thermotolerance, maximal growth rate, and yield on light following adaptive laboratory evolution BMC Biology Adaptive laboratory evolution Microalgae Temperature Picochlorum Photobioreactor Genome assembly |
| title | Genetic mechanisms underlying increased microalgal thermotolerance, maximal growth rate, and yield on light following adaptive laboratory evolution |
| title_full | Genetic mechanisms underlying increased microalgal thermotolerance, maximal growth rate, and yield on light following adaptive laboratory evolution |
| title_fullStr | Genetic mechanisms underlying increased microalgal thermotolerance, maximal growth rate, and yield on light following adaptive laboratory evolution |
| title_full_unstemmed | Genetic mechanisms underlying increased microalgal thermotolerance, maximal growth rate, and yield on light following adaptive laboratory evolution |
| title_short | Genetic mechanisms underlying increased microalgal thermotolerance, maximal growth rate, and yield on light following adaptive laboratory evolution |
| title_sort | genetic mechanisms underlying increased microalgal thermotolerance maximal growth rate and yield on light following adaptive laboratory evolution |
| topic | Adaptive laboratory evolution Microalgae Temperature Picochlorum Photobioreactor Genome assembly |
| url | https://doi.org/10.1186/s12915-022-01431-y |
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