title: Highly efficient lipid production in the green alga Parachlorella kessleri: draft genome and transcriptome endorsed by whole-cell 3D ultrastructure.
abstract: BACKGROUND
  Algae have attracted attention as sustainable producers of lipid-containing biomass for food, animal feed, and for biofuels. Parachlorella kessleri, a unicellular green alga belonging to the class Trebouxiophyceae, achieves very high biomass, lipid, and starch productivity levels. However, further biotechnological exploitation has been hampered by a lack of genomic information.
  
  
  RESULTS
  Here, we sequenced the whole genome and transcriptome, and analyzed the behavior of P. kessleri NIES-2152 under lipid production-inducing conditions. The assembly includes 13,057 protein-coding genes in a 62.5-Mbp nuclear genome. Under conditions of sulfur deprivation, lipid accumulation was correlated with the transcriptomic induction of enzymes involved in sulfur metabolism, triacylglycerol (TAG) synthesis, autophagy, and remodeling of light-harvesting complexes.
  
  
  CONCLUSIONS
  Three-dimensional transmission electron microscopy (3D-TEM) revealed extensive alterations in cellular anatomy accompanying lipid hyperaccumulation. The present 3D-TEM results, together with transcriptomic data support the finding that upregulation of TAG synthesis and autophagy are potential key mediators of the hyperaccumulation of lipids under conditions of nutrient stress.
authors.affiliation: Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562 Japan.|Japan Science and Technology Agency (JST), CREST, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562 Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Ota
authors.affiliation: Center for Omics and Bioinformatics, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 Japan.
authors.forename: Kenshiro
authors.initials: K
authors.lastname: Oshima
authors.affiliation: Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562 Japan.|Japan Science and Technology Agency (JST), CREST, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562 Japan.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Yamazaki
authors.affiliation: Center for Omics and Bioinformatics, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 Japan.|Department of Genetic Resources Technology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan.
authors.forename: Sangwan
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562 Japan.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Yu
authors.affiliation: Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562 Japan.
authors.forename: Mai
authors.initials: M
authors.lastname: Yoshihara
authors.affiliation: Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562 Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Takeda
authors.affiliation: Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562 Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Takeshita
authors.affiliation: Bioimaging Center, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562 Japan.
authors.forename: Aiko
authors.initials: A
authors.lastname: Hirata
authors.affiliation: Institute of Microbiology, CAS, Centre Algatech, Laboratory of Cell Cycles of Algae, Opatovický mlýn, 379 81 Třeboň, Czech Republic.
authors.forename: Kateřina
authors.initials: K
authors.lastname: Bišová
authors.affiliation: Institute of Microbiology, CAS, Centre Algatech, Laboratory of Cell Cycles of Algae, Opatovický mlýn, 379 81 Třeboň, Czech Republic.
authors.forename: Vilém
authors.initials: V
authors.lastname: Zachleder
authors.affiliation: Center for Omics and Bioinformatics, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 Japan.
authors.forename: Masahira
authors.initials: M
authors.lastname: Hattori
authors.affiliation: Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562 Japan.|Japan Science and Technology Agency (JST), CREST, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562 Japan.
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Kawano
keywords: 3D-TEM; Genome; Green alga; Lipid body; Parachlorella kessleri; RNA-seq; Transcriptome; Whole-genome sequence
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