Whole genome re-sequencing identifies a quantitative trait locus repressing carbon reserve accumulation during optimal growth in $Chlamydomonas\ reinhardtii$
Résumé
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 >200kb 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.
Domaines
Sciences du Vivant [q-bio]Origine | Fichiers éditeurs autorisés sur une archive ouverte |
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