Lipidomic analysis of two closely related strains of the microalga Parietochloris (Trebouxiophyceae, Chlorophyta)
Abstract
The analysis of ribosomal internal transcribed spacer 2 (ITS2) secondary structure and morphology of two strains of the green microalga Parietochloris (CCALA 1082 and 1084) confirmed that they represent one biological species. However, their fatty acid profiles showed slight differences, which was fully confirmed by a series of lipidomic analyses using both shotgun lipidomics and hydrophilic interaction liquid chromatography-tandem mass spectrometry with electrospray ionization. 26 classes of lipids were identified, including more than 430 molecular species of lipids.
The analyses showed that the greatest differences are in three types of phospholipids -phosphatidylethanolamine, phosphatidylcholine and phosphatidylinositol. These phospholipids have different spatial configurations (cylindrical, conical, and conical inverted), especially for those molecular species containing at least one arachidonic acid.
Based on the lipidomic analyses we were able to distinguish the two strains. This may be advantageous in cases when routine DNA analysis shows that two strains are nearly identical.