Abstract
Phosphatidylserine (PS) represents 10% of total lipids from flowers in A. thaliana, where PS biosynthesis is regulated by the base-exchange-type PS synthase gene AtPSS1 (At1g15110). To understand the role of PS in reproductive development, we previously showed that the null alleles pss1-1 (T-DNA insertion) and pss1-2 (EMS-tilling) mostly showed embryonic lethality and that heterozygotic mutants partly showed cell death of pollen microspores. To extend our understanding of the role of PS in pollen development, we herein isolated homozygotes for pss1-1 and pss1-2mutants. Homozygous pss1-1 and pss1-2 plants were raised to show dwarfism and produce infertile flowers. Pollen grains were found on the stigma, but no fertile embryo was found within the ovary. Pollen from homozygotic mutants partly showed leakage of cytoplasmic materials through the cell wall, suggestive of damaged cell walls due to malfunction of tapete cells.
