XVI International Botanical Congess

In most angiosperms the endosperm contains a ratio of 2 maternal to 1 paternal genomes. This ratio is essential for normal seed development, most likely reflecting activity of imprinted (uniparentally expressed) genes. We recently reported the effects of changing the parental genome ratio in Arabidopsis seeds. Crosses between 2x and 4x plants, resulting in a double dose of maternal or paternal genomes, produced viable seeds containing 3x embryos, while seeds from crosses between 2x and 6x plants aborted. Confocal microscopy showed that in both sets of crosses, seed development was abnormal, with maternal and paternal excess producing complementary phenotypes. We are continuing to investigate seed development following interploidy crosses, to further study the role of imprinted genes in seed development.