title: Expression of fatty acid synthesis genes and fatty acid accumulation in haematococcus pluvialis under different stressors.
abstract: BACKGROUND
  Biofuel has been the focus of intensive global research over the past few years. The development of 4th generation biofuel production (algae-to-biofuels) based on metabolic engineering of algae is still in its infancy, one of the main barriers is our lacking of understanding of microalgal growth, metabolism and biofuel production. Although fatty acid (FA) biosynthesis pathway genes have been all cloned and biosynthesis pathway was built up in some higher plants, the molecular mechanism for its regulation in microalgae is far away from elucidation.
  
  
  RESULTS
  We cloned main key genes for FA biosynthesis in Haematococcus pluvialis, a green microalga as a potential biodiesel feedstock, and investigated the correlations between their expression alternation and FA composition and content detected by GC-MS under different stress treatments, such as nitrogen depletion, salinity, high or low temperature. Our results showed that high temperature, high salinity, and nitrogen depletion treatments played significant roles in promoting microalgal FA synthesis, while FA qualities were not changed much. Correlation analysis showed that acyl carrier protein (ACP), 3-ketoacyl-ACP-synthase (KAS), and acyl-ACP thioesterase (FATA) gene expression had significant correlations with monounsaturated FA (MUFA) synthesis and polyunsaturated FA (PUFA) synthesis.
  
  
  CONCLUSIONS
  We proposed that ACP, KAS, and FATA in H. pluvialis may play an important role in FA synthesis and may be rate limiting genes, which probably could be modified for the further study of metabolic engineering to improve microalgal biofuel quality and production.
authors.affiliation: Shenzhen Key Laboratory for Marine Bio-resource and Eco-environment, College of Life Sciences, Shenzhen University, Shenzhen 518060, P. R. China.
authors.forename: Anping
authors.initials: A
authors.lastname: Lei
authors.affiliation: Shenzhen Key Laboratory for Marine Bio-resource and Eco-environment, College of Life Sciences, Shenzhen University, Shenzhen 518060, P. R. China.
authors.forename: Huan
authors.initials: H
authors.lastname: Chen
authors.affiliation: School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310012, P. R. China.
authors.forename: Guoming
authors.initials: G
authors.lastname: Shen
authors.affiliation: Shenzhen Key Laboratory for Marine Bio-resource and Eco-environment, College of Life Sciences, Shenzhen University, Shenzhen 518060, P. R. China.
authors.forename: Zhangli
authors.initials: Z
authors.lastname: Hu
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin, People's Republic of China.|Center for Biosignature Discovery Automation, Biodesign Institute, Arizona State University, Tempe AZ 85287, USA.
authors.forename: Jiangxin
authors.initials: J
authors.lastname: Wang