Identification and mechanism analysis of chemical modulators enhancing astaxanthin accumulation in Haematococcus pluvialis

Haematococcus pluvialis is one natural source for high-value anti-oxidant astaxanthin. In this study, we evaluated 23 chemicals of 8 groups (antioxidant, oxidant, signal transducer, metal ion, auxin, gibberellin, cytokinin and amine) for their effects on astaxanthin accumulation in H. pluvialis. The results showed that oxidant and signal transduction chemicals increased astaxanthin accumulation in H. pluvialis significantly by more than 20%. To reveal possible regulatory mechanism, a gas chromatography-mass spectrometry (GC-MS) and a liquid chromatography-mass spectrometry (LC-MS) based metabolomic analysis were applied to determine metabolic profiles of H. pluvialis treated with chemical modulators, and then the metabolomic data was analyzed by a partial least squares-discriminate analysis (PLS-DA) and a weighted correlation network analysis (WGCNA) to identify possible metabolic modules and metabolites relevant to the increased astaxanthin accumulation. The analyses showed six metabolic modules and seven hub metabolites were possibly related to the stimulatory roles of oxidant or signal transduction in H. pluvialis. The study provided new insights to the regulatory mechanism of oxidant and signal transduction chemicals on astaxanthin accumulation in H. pluvialis. (C) 2015 Elsevier B.V. All rights reserved.