Metabolomics analysis of phytohormone gibberellin improving lipid and DHA accumulation in Aurantiochytrium sp.

• Investigate effects of gibberellin on biomass, lipid and DHA yield.
• Discover metabolic profile changes induced by gibberellin.
• Reveal changed metabolism associated with increased lipid and DHA accumulation.
• The anti-stress mechanism could also be induced by gibberellin.

In this study, the phytohormone gibberellin was evaluated for its effect on lipid and docosahexaenoic acid (DHA) accumulation in Aurantiochytrium sp.YLH70. It was found that 4 mg/mL of gibberellin increased biomass, lipid and DHA yield of Aurantiochytrium sp.YLH70 by 14.4%, 43.6% and 79.1%, respectively. Moreover, a GC–MS metabolomics method combined with a multivariate analysis was applied to reveal the metabolic mechanisms responsible for the increased lipid and DHA accumulation. The principal component analysis (PCA) revealed that metabolomics profiles from all groups were discriminated. 38 metabolites identified by the partial least-squares-discriminant analysis (PLS-DA) were responsible for responding to gibberellin treatment. Metabolic pathway analysis showed that gibberellin accelerated the rate of utilization of glucose, and metabolites in fatty acids biosynthesis and mevalonate pathway were increased, while metabolites in glycolysis and TCA cycle were decreased in Aurantiochytrium sp.YLH70. Moreover, the anti-stress mechanism in Aurantiochytrium sp.YLH70 might be induced by gibberellin.

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