title: RNA-seq based identification and mutant validation of gene targets related to ethanol resistance in cyanobacterial Synechocystis sp. PCC 6803.
abstract: BACKGROUND
  Fermentation production of biofuel ethanol consumes agricultural crops, which will compete directly with the food supply. As an alternative, photosynthetic cyanobacteria have been proposed as microbial factories to produce ethanol directly from solar energy and CO2. However, the ethanol productivity from photoautotrophic cyanobacteria is still very low, mostly due to the low tolerance of cyanobacterial systems to ethanol stress.
  
  
  RESULTS
  To build a foundation necessary to engineer robust ethanol-producing cyanobacterial hosts, in this study we applied a quantitative transcriptomics approach with a next-generation sequencing technology, combined with quantitative reverse-transcript PCR (RT-PCR) analysis, to reveal the global metabolic responses to ethanol in model cyanobacterial Synechocystis sp. PCC 6803. The results showed that ethanol exposure induced genes involved in common stress responses, transporting and cell envelope modification. In addition, the cells can also utilize enhanced polyhydroxyalkanoates (PHA) accumulation and glyoxalase detoxication pathway as means against ethanol stress. The up-regulation of photosynthesis by ethanol was also further confirmed at transcriptional level. Finally, we used gene knockout strains to validate the potential target genes related to ethanol tolerance.
  
  
  CONCLUSIONS
  RNA-Seq based global transcriptomic analysis provided a comprehensive view of cellular response to ethanol exposure. The analysis provided a list of gene targets for engineering ethanol tolerance in cyanobacterium Synechocystis.
authors.affiliation: School of Chemical Engineering & Technology, Tianjin University, Tianjin, 300072, People's Republic of China. wwzhang8@tju.edu.cn.
authors.forename: Jiangxin
authors.initials: J
authors.lastname: Wang
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.forename: Siqiang
authors.initials: S
authors.lastname: Huang
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: Xiaoyue
authors.initials: X
authors.lastname: Ren
authors.forename: Xiaoxu
authors.initials: X
authors.lastname: Tian
authors.forename: Jianjun
authors.initials: J
authors.lastname: Qiao
authors.forename: Weiwen
authors.initials: W
authors.lastname: Zhang