title: Whole Genome Re-Sequencing Identifies a Quantitative Trait Locus Repressing Carbon Reserve Accumulation during Optimal Growth in Chlamydomonas reinhardtii.
abstract: Microalgae have emerged as a promising source for biofuel production. Massive oil and starch accumulation in microalgae is possible, but occurs mostly when biomass growth is impaired. The molecular networks underlying the negative correlation between growth and reserve formation are not known. Thus isolation of strains capable of accumulating carbon reserves during optimal growth would be highly desirable. To this end, we screened an insertional mutant library of Chlamydomonas reinhardtii for alterations in oil content. A mutant accumulating five times more oil and twice more starch than wild-type during optimal growth was isolated and named constitutive oil accumulator 1 (coa1). Growth in photobioreactors under highly controlled conditions revealed that the increase in oil and starch content in coa1 was dependent on light intensity. Genetic analysis and DNA hybridization pointed to a single insertional event responsible for the phenotype. Whole genome re-sequencing identified in coa1 a >200 kb deletion on chromosome 14 containing 41 genes. This study demonstrates that, 1), the generation of algal strains accumulating higher reserve amount without compromising biomass accumulation is feasible; 2), light is an important parameter in phenotypic analysis; and 3), a chromosomal region (Quantitative Trait Locus) acts as suppressor of carbon reserve accumulation during optimal growth.
authors.affiliation: CEA, BIAM, Lab Bioenerget Biotechnol Bacteries &Microalgues, Saint-Paul-lez-Durance, 13108, France.|CNRS, UMR 7265 Biol Veget &Microbiol Environ, Saint-Paul-lez-Durance, 13108, France.|Aix Marseille Université, BVME UMR7265, Marseille, 13284, France.|Faculty of Agriculture and the Environment, University of Sydney, Australia.
authors.forename: Hugh Douglas
authors.initials: HD
authors.lastname: Goold
authors.affiliation: CEA, BIAM, Lab Bioenerget Biotechnol Bacteries &Microalgues, Saint-Paul-lez-Durance, 13108, France.|CNRS, UMR 7265 Biol Veget &Microbiol Environ, Saint-Paul-lez-Durance, 13108, France.|Aix Marseille Université, BVME UMR7265, Marseille, 13284, France.
authors.forename: Hoa Mai
authors.initials: HM
authors.lastname: Nguyen
authors.affiliation: CEA, BIAM, Lab Bioenerget Biotechnol Bacteries &Microalgues, Saint-Paul-lez-Durance, 13108, France.|CNRS, UMR 7265 Biol Veget &Microbiol Environ, Saint-Paul-lez-Durance, 13108, France.|Aix Marseille Université, BVME UMR7265, Marseille, 13284, France.
authors.forename: Fantao
authors.initials: F
authors.lastname: Kong
authors.affiliation: CEA, BIAM, Lab Bioenerget Biotechnol Bacteries &Microalgues, Saint-Paul-lez-Durance, 13108, France.|CNRS, UMR 7265 Biol Veget &Microbiol Environ, Saint-Paul-lez-Durance, 13108, France.|Aix Marseille Université, BVME UMR7265, Marseille, 13284, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Beyly-Adriano
authors.affiliation: CEA, BIAM, Lab Bioenerget Biotechnol Bacteries &Microalgues, Saint-Paul-lez-Durance, 13108, France.|CNRS, UMR 7265 Biol Veget &Microbiol Environ, Saint-Paul-lez-Durance, 13108, France.|Aix Marseille Université, BVME UMR7265, Marseille, 13284, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Légeret
authors.affiliation: CEA, BIAM, Lab Bioenerget Biotechnol Bacteries &Microalgues, Saint-Paul-lez-Durance, 13108, France.|CNRS, UMR 7265 Biol Veget &Microbiol Environ, Saint-Paul-lez-Durance, 13108, France.|Aix Marseille Université, BVME UMR7265, Marseille, 13284, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Billon
authors.affiliation: CEA, BIAM, Lab Bioenerget Biotechnol Bacteries &Microalgues, Saint-Paul-lez-Durance, 13108, France.|CNRS, UMR 7265 Biol Veget &Microbiol Environ, Saint-Paul-lez-Durance, 13108, France.|Aix Marseille Université, BVME UMR7265, Marseille, 13284, France.
authors.forename: Stéphan
authors.initials: S
authors.lastname: Cuiné
authors.affiliation: CEA, BIAM, Lab Bioenerget Biotechnol Bacteries &Microalgues, Saint-Paul-lez-Durance, 13108, France.|CNRS, UMR 7265 Biol Veget &Microbiol Environ, Saint-Paul-lez-Durance, 13108, France.|Aix Marseille Université, BVME UMR7265, Marseille, 13284, France.
authors.forename: Fred
authors.initials: F
authors.lastname: Beisson
authors.affiliation: CEA, BIAM, Lab Bioenerget Biotechnol Bacteries &Microalgues, Saint-Paul-lez-Durance, 13108, France.|CNRS, UMR 7265 Biol Veget &Microbiol Environ, Saint-Paul-lez-Durance, 13108, France.|Aix Marseille Université, BVME UMR7265, Marseille, 13284, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Peltier
authors.affiliation: CEA, BIAM, Lab Bioenerget Biotechnol Bacteries &Microalgues, Saint-Paul-lez-Durance, 13108, France.|CNRS, UMR 7265 Biol Veget &Microbiol Environ, Saint-Paul-lez-Durance, 13108, France.|Aix Marseille Université, BVME UMR7265, Marseille, 13284, France.
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Li-Beisson
mesh_terms: D002244:Carbon / Q000378:metabolism*; D016825:Chlamydomonas reinhardtii / Q000254:growth & development* / Q000378:metabolism* / Q000528:radiation effects; D008027:Light; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D009154:Mutation; D009821:Oils / Q000378:metabolism; D040641:Quantitative Trait Loci; D017422:Sequence Analysis, DNA; D013213:Starch / Q000378:metabolism
chemical_list: D009821:Oils; D002244:Carbon; D013213:Starch