Using Transcriptomics To Improve Butanol Tolerance of Synechocystis sp Strain PCC 6803
Using Transcriptomics To Improve Butanol Tolerance of Synechocystis sp Strain PCC 6803
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DOI：
10.1128/aem.02694-13
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发表时间：
2013-12-01
影响因子：
4.4
通讯作者：
Hudson, Elton P.
中科院分区：
文献类型：
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作者：
Anfelt, Josefine;Hallstrom, Bjorn;Hudson, Elton P.
蓝藻正在成为生产先进生物燃料（如正丁醇和烷烃）的有前途的宿主。然而，蓝藻遭受相同的产品抑制问题，困扰其他微生物生物燃料主机。高浓度的丁醇会严重降低生长，即使是少量的丁醇也会对代谢过程产生负面影响。了解蓝藻如何受到其生物燃料产品的影响，可以确定提高其耐受性的工程策略。在这里，我们使用转录组测序（RNA-Seq）来评估集胞藻菌株PCC 6803对两种浓度的外源正丁醇的转录组响应。大约80个转录本在40 mg/L丁醇中差异表达，280个转录本在1 g/L丁醇中不同。我们的研究结果表明，受损的细胞膜，受损的光合电子传递，减少生物合成。细胞内活性氧（ROS）的积累与丁醇浓度成比例。利用生理学和转录组学数据，我们选择了几个基因过表达，试图提高丁醇耐受性。我们发现，过表达的几种蛋白质，特别是小的热休克蛋白HspA，提高耐受丁醇。转录组学指导的工程创造了更耐溶剂的蓝藻菌株，这可能是生产更高效的生物燃料宿主的基础。
Cyanobacteria are emerging as promising hosts for production of advanced biofuels such as n-butanol and alkanes. However, cyanobacteria suffer from the same product inhibition problems as those that plague other microbial biofuel hosts. High concentrations of butanol severely reduce growth, and even small amounts can negatively affect metabolic processes. An understanding of how cyanobacteria are affected by their biofuel product can enable identification of engineering strategies for improving their tolerance. Here we used transcriptome sequencing (RNA-Seq) to assess the transcriptome response of Synechocystis sp. strain PCC 6803 to two concentrations of exogenous n-butanol. Approximately 80 transcripts were differentially expressed at 40 mg/liter butanol, and 280 transcripts were different at 1 g/liter butanol. Our results suggest a compromised cell membrane, impaired photosynthetic electron transport, and reduced biosynthesis. Accumulation of intracellular reactive oxygen species (ROS) scaled with butanol concentration. Using the physiology and transcriptomics data, we selected several genes for overexpression in an attempt to improve butanol tolerance. We found that overexpression of several proteins, notably, the small heat shock protein HspA, improved tolerance to butanol. Transcriptomics-guided engineering created more solvent-tolerant cyanobacteria strains that could be the foundation for a more productive biofuel host.