Maternal effects of the short integument mutation on embryo development in Arabidopsis.
Maternal gene products deposited in an animal egg determine the polarity of embryonic axes and regulate embryonic cell-cell communication important for morphogenesis. Here we report the first maternal-effect embryo-defective mutation discovered in a plant. Recessive mutations in the SHORT INTEGUMENT (SIN1) gene in Arabidopsis were previously shown to influence ovule development and flowering time. Here we show that a sin1 mutation has a pronounced maternal effect on zygotic embryo development. A homozygous sin1 mutant embryo is normal when nursed by a sin1/+ heterozygous maternal sporophyte. Strikingly, a sin1 or a sin1/+ embryo that is nursed by a sin1 homozygous maternal sporophyte develops morphogenetic defects in the apical-basal and radial axes. The defects resemble those seen in some zygotic-effect embryonic pattern formation mutants. These results imply that in maternal cells the SIN1 gene either codes for or controls the production of a diffusible morphogen necessary for proper zygotic embryogenesis.
Ray
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Department of Biology, University of Rochester, New York 14627, USA.
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D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D002455:Cell Division; D017343:Genes, Plant; D005808:Genes, Recessive; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics*; D012639:Seeds / Q000502:physiology; D015053:Zygote / Q000502:physiology
D010940:Plant Proteins