MetaboLights MTBLS1714 - GNPS A metabolomics exploration of the sexual phase in the marine diatom Pseudo-nitzschia multistriata

ABSTRACT: Pseudo-nitzschia multistriata is a planktonic diatom species with a diplontic life cycle comprising a short sexual phase during which gametes are produced from the encounter of two diploid cells of opposite mating type (MT). Gene expression studies have highlighted the presence of substantial changes occurring at the onset of sexual reproduction. Collectively, there is clear evidence of a chemical cross talk which mediates the mating step. Herein, we have hypothesized that these major transcriptomic changes are associated to variations in the amount and nature of the metabolites produced by the cells. In order to investigate such chemical diversity in an unbiased manner, we undertook an untargeted metabolomics approach. Liquid chromatography – tandem mass spectrometry was applied to investigate the differences in the metabolic profiles between control cells in the vegetative phase (MT+ and MT-) and mixed strains of opposite MTs (cross) undergoing sexual reproduction. Of the 2408 high-quality features obtained, 70 known metabolites could be identified based on in-house libraries and online databases; molecular networking proved valuable to classify additional 47 non-identified features. The present exploratory study provides an overview of the chemical diversity detectable in P. multistriata, presenting a dynamic picture of the changes occurring during sexual reproduction. In particular, the reduction of phytol detected in the cross can be linked to the general downregulation of photosynthesis during sexual reproduction observed elsewhere. The dysregulation of other metabolites stands as a starting point for the understanding of the mechanisms regulating sexual reproduction: a metabolite that was tentatively identified as 7-dehydrodesmosterol exhibited the highest upregulation in the comparison between the two MTs of opposite sex, as well as between MT+ vs cross. The effects of extraction solvents and harvesting times on the ensemble of endo-metabolites were also analyzed.

INSTRUMENT(S): Bruker Daltonics maXis series|1001547

ORGANISM(S): Pseudo-nitzschia Multistriata|183589

SUBMITTER: Federica Fiorini  

PROVIDER: MSV000085769 | GNPS | Thu Jul 16 15:01:00 BST 2020

REPOSITORIES: GNPS