Expression of a Cyanobacterial C18-acyl-specific Lysophosphatidic Acid Acyltransferase Gene in Arabidopsis ats2 Mutants

Abstract

Photosynthetic organisms contain C16 fatty acids in the sn-2 positions of glycerolipids, which is largely controlled by the substrate specificity of lysophosphatidic acid acyltransferases (LPAAT). The cyanobacterium Synechocystis sp. PCC6803 contains two LPAAT genes, i.e., sll1848 for C16-acyl-specific LPAAT and sll1752 for C18-acyl-specific LPAAT. A knock-out mutant for sll1848 unusually contains C18-fatty acids in the sn-2 positions of glycerolipids and shows slower photosynthetic growth compared to the wild type. Phosphatidylglycerol (PG) in higher-plant plastids contains palmitate or trans-3-hexadecenoic acids in the sn-2 position. To evaluate the significance of fatty acid composition in the sn-2 position of PG, we introduced a recombinant sll1752 gene into an ats2 mutant that is null for plastid-targeted LPAAT of Arabidopsis thaliana. We will report the effect of gene expression on the fatty acid composition of PG as well as the growth phenotype of the transgenic plants.