Abstract
Phosphatidylglycerol (PG) is a phospholipid found in biological membranes. In plant cells, biosynthesis of PG occurs in plastids, mitochondria and ER. In Arabidopsis thaliana, PGP1 and PGP2 encoding a phoshphatidylglycerophosphate synthase involved in the biosynthesis of PG were identified. A pgp1 mutant isolated from A. thaliana can develop normal mitochondria but not normal chloroplasts. It was suggested that PG synthesized in ER is transported to mitochondria and compensated the defect in the biosynthesis of PG in mitochondria. In this study, we isolated pgp2 mutant to investigate the function of PG synthesized in ER.
The isolated pgp2-1 mutant showed no growth defect under normal growth conditions and double mutant pgp1 pgp2-1 was not isolated. Analysis of embryos obtained by self-pollination of PGP1/pgp1 pgp2-1/pgp2-1 suggested that development of embryos in the double mutant was arrested. To characterize the expression profiles of PGP1 and PGP2, we performed histochemical analysis of the genes using GUS assays. In the case of PGP1, strong GUS activity was detected in vascular tissues, guard cells, and trichome accessory cells in young leaves.
