Phosphatidylglycerol biosynthesis is required for the development of embryos and normal membrane structures of chloroplasts and mitochondria in Arabidopsis

•Seeds of pgp1pgp2 double mutants of Arabidopsis cannot germinate.•Embryos of pgp1pgp2 double mutants of Arabidopsis cannot synthesize PG.•PG is required for embryo development in Arabidopsis.•PG is required for normal membrane structure of chloroplasts and mitochondria. Phosphatidylglycerophosphate (PGP) synthase, encoded by PGP1 and PGP2 in Arabidopsis, catalyzes a committed step in the biosynthesis of phosphatidylglycerol (PG). In this study, we isolated a pgp1pgp2 double mutant of Arabidopsis to study the function of PG. In this mutant, embryo development was delayed and the majority of seeds did not germinate. Thylakoid membranes did not develop in plastids, mitochondrial membrane structures were abnormal in the mutant embryos, and radiolabeling of phospholipids showed that radioactivity was not significantly incorporated into PG. These results demonstrated that PG biosynthesis is essential for the development of embryos and normal membrane structures of chloroplasts and mitochondria.