ABSTRACT
Phosphate is vital for plant and algae growth, yield, and survival, but in most environments, it is poorly available. To cope with phosphate starvation, photosynthetic organisms used their phospholipids as a phosphate reserve. In microalgae, betaine lipids replace phospholipids whereas, in higher plants, betaine lipid synthesis is lost, driving plants to other strategies. The aim of this work was to evaluate to what extent betaine lipids and PC lipids share physicochemical properties and could thus substitute each other. Using neutron diffraction and molecular dynamics simulations of two synthetic lipids, dipalmitoylphosphatidylcholine (DPPC) and dipalmitoyl-diacylglyceryl-N,N,N-trimethylhomoserine (DP-DGTS), we show that DP-DGTS bilayers are thicker, more rigid, and mutually more repulsive than DPPC bilayers. The different properties and hydration response of PC and DGTS provide an explanation for the diversity of betaine lipids observed in marine organisms and for their disappearance in seed plants.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Financial sources: This work was supported by ANR-DFG ANR-18-CE92-0015 and SCHN 1396/2. SB was supported by a joint funding Glyco@Alps / ILL PhD Program, by the French National Research Agency in the framework of the “Investissements d’avenir” program Glyco@Alps (ANR-15-IDEX-02), “Origin Of Life” (ANR-17-EURE-0003), “Oceanomics” (ANR-11-BTBR-0008) and the Labex GRAL, financed within the University Grenoble Alpes graduate school (Ecoles Universitaires de Recherche) CBH-EUR-GS (ANR-17-EURE-0003). AS acknowledges funding from the DFG under Germany’s Excellence Strategy – EXC 2075 – 390740016. Computing time was provided by the state of Baden-Württemberg through bwHPC.
Data Availability Statement: The data that support the findings of this study are openly available at https://doi.ill.fr/10.5291/ILL-DATA.8-02-220, https://doi.ill.fr/10.5291/ILL-DATA.TEST-3119 and at https://doi.org/10.18419/darus-2360.
Conflict of Interest Statement : The authors declare no conflicts of interest
