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| Status |
Public on Aug 06, 2013 |
| Title |
Transcriptomic response to long time ethanol production in the cyanobacterium Synechocystis sp. PCC6803 |
| Organism |
Synechocystis sp. PCC 6803 |
| Experiment type |
Expression profiling by array
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| Summary |
The production of biofuels in photosynthetic microalgae and cyanobacteria is considered a promising alternative to the generation of fuels from fossil resources. However, to be economically competitive, producer strains need to be established that synthesize the targeted product at high yield and over a long time. Engineering cyanobacteria to forced fuel producers should considerably interfere with overall cell homeostasis, which in turn might counteract productivity and sustainability of the process. Therefore, in-depth characterization of the cellular response upon long-term production is of high interest for the targeted improvement of a desired strain. Here we report the results of a monitoring experiment, in which the transcriptome-wide response to continuous ethanol production in the unicellular model cyanobacterium Synechocystis sp. PCC6803 was examined using high resolution microarrays. In two independent experiments, ethanol production rates of 0.0338% (v/v) EtOH d-1 ± 0.002 and 0.0303% (v/v) d-1 ± 0.002 were obtained over 18 consecutive days, measuring biological triplicates in fully automated photobioreactors. Ethanol production caused a significant (~40%) delay in biomass accumulation in the producer strains and the development of a bleaching phenotype. Absorption spectroscopy indicated in particular a down-regulation of light harvesting capacity. Microarray analyses performed at day 4, 7, 11 and 18 of the experiment revealed only three mRNAs with a strongly modified accumulation level throughout the course of the experiment. In addition to the overexpressed adhA (slr1192) gene, this was an about 4 fold reduction in cpcB (sll1577) and an about 3 to 6 fold increase in rps8 (sll1809) mRNA levels. Much weaker modifications of expression level or modifications restricted to day 18 of the experiment were observed for genes involved in carbon assimilation (Ribulose bisphosphate carboxylase and Glutamate decarboxylase). Molecular analysis of the reduced cpcB levels revealed a post-transcriptional operon discoordination in the cpcBA operon leaving a truncated mRNA cpcA* likely not competent for translation. Moreover, Western blots and zinc-enhanced bilin fluorescence blots confirmed a severe reduction in the amounts of both phycocyanin subunits, explaining the cause of the bleaching phenotype. We conclude that the changes in gene expression upon induction of long term ethanol production in Synechocystis sp. PCC6803 are highly specific. in particular we did not observe a comprehensive stress response contributing to a complex phenotype as might have been expected.
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| Overall design |
Gene expression of Synechocystis sp. PCC 6803 WT (#621) and the isogenic ethanol producing strain #309 was monitored at 4, 7, 11 and 18 days after induction of ethanol production by copper depletion. Each condition was sampled in biological duplicates
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| Contributor(s) |
Dienst D, Georg J, Abts T, Jakorew L, Kuchmina E, Wilde A, Dühring U, Enke H, Hess WR |
| Citation(s) |
24502290 |
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| Submission date |
Aug 05, 2013 |
| Last update date |
Jan 23, 2017 |
| Contact name |
Jens Georg |
| E-mail(s) |
[email protected]
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| Organization name |
University of Freiburg
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| Street address |
Schänzlestr. 1
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| City |
Freiburg |
| ZIP/Postal code |
79104 |
| Country |
Germany |
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| Platforms (1) |
| GPL15867 |
Agilent-027432 Syn6803_expressions454_4-3probes |
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| Samples (16)
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| GSM1201667 |
PCC6803_producer_4d_copper_depletion 309_4d-1 |
| GSM1201668 |
PCC6803_producer_4d_copper_depletion 309_4d-2 |
| GSM1201669 |
PCC6803_WT_4d_copper_depletion 621_4d-1 |
| GSM1201670 |
PCC6803_WT_4d_copper_depletion 621_4d-2 |
| GSM1201671 |
PCC6803_producer_7d_copper_depletion 309_7d-1 |
| GSM1201672 |
PCC6803_producer_7d_copper_depletion 309_7d-2 |
| GSM1201673 |
PCC6803_WT_7d_copper_depletion 621_7d-1 |
| GSM1201674 |
PCC6803_WT_7d_copper_depletion 621_7d-2 |
| GSM1201675 |
PCC6803_producer_11d_copper_depletion 309_11d-1 |
| GSM1201676 |
PCC6803_producer_11d_copper_depletion 309_11d-2 |
| GSM1201677 |
PCC6803_WT_11d_copper_depletion 621_11d-1 |
| GSM1201678 |
PCC6803_WT_11d_copper_depletion 621_11d-2 |
| GSM1201679 |
PCC6803_producer_18d_copper_depletion 309_18d-1 |
| GSM1201680 |
PCC6803_producer_18d_copper_depletion 309_18d-2 |
| GSM1201681 |
PCC6803_WT_18d_copper_depletion 621_18d-1 |
| GSM1201682 |
PCC6803_WT_18d_copper_depletion 621_18d-2 |
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| Relations |
| BioProject |
PRJNA214237 |
| Supplementary file |
Size |
Download |
File type/resource |
| GSE49552_RAW.tar |
82.3 Mb |
(http)(custom) |
TAR (of TXT) |
| Processed data included within Sample table |
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