Abstract
Phosphatidylglycerol (PG) is a phospholipid found in biological membranes. In plant cells, PG is mainly localized in thylakoid membranes and required for photosynthesis. To investigate the function of PG, we isolated pgp1 and pgp2 mutants of Arabidopsis thaliana, which have disrupted PGP1 and PGP2 genes for phosphatidylglycerophosphate synthases involved in the biosynthesis of PG. Glycerolipid profiles of the pgp1 and pgp2 mutants showed that PGP1 mainly contributes to PG biosynthesis in leaves, while PGP2 has only a minor contribution. To make the double mutant that cannot synthesize PG at all, the pgp1 mutant was crossed to the pgp2 mutant. Although the double mutant was not isolated, we found that 25% of seeds were albino and wrinkled when PGP1/pgp1 pgp2/pgp2 plants were self-fertilized. Embryo development in the albino and wrinkled seeds was delayed and not fully matured, and the embryos had short cotyledons. These findings suggested that PG has important roles in embryo development, growth of cotyledons and chloroplast differentiation.
