New genomic insights into long-chain alkenone biosynthesis by the coccolithophorid marine alga Gephyrocapsa huxleyi.

backgroundGephyrocapsa huxleyi is a coccolithophoric haptophyte widespread across most marine ecosystems that plays an important role in the carbon cycle. G. huxleyi is one of the few haptophytes known to produce long-chain alkenones (LCAs), which are lipids composed of C

resultsTo evaluate differences in LCA biosynthesis under changing conditions, we developed a tailored approach to decontaminate and assemble the genomes of two additional non-axenic G. huxleyi strains (strains CCMP1742 and CCMP2758) that produce LCAs with two to four double bonds, one of which (CCMP2758) also produces unusually short (C

conclusionsHere, we advance the understanding of biosynthesis of LCAs, important molecules for paleotemperature reconstruction, in the marine haptophyte G. huxleyi. By assembling the genomes of two LCA-producing strains, we were able to overcome the limitations of the scarcity of reference genomes of this group, enabling the analysis of gene expression under varying growth conditions and the identification of PKSs and desaturases potentially involved in LCA biosynthesis. These findings constitute a step forward in elucidating the genetic basis for LCA production and regulation in G. huxleyi, which not only advances our understanding on how LCAs are formed but also aids in the improvement of LCA-based paleotemperature reconstructions.