title: Auxin-dependent patterning and gamete specification in the Arabidopsis female gametophyte.
abstract: The female reproductive unit of flowering plants, the haploid female gametophyte, is highly reduced relative to other land plants. We show that patterning of the Arabidopsis female gametophyte depends on an asymmetric distribution of the hormone auxin during its syncitial development. Furthermore, this auxin gradient is correlated with location-specific auxin biosynthesis, rather than auxin efflux that directs patterning in the diploid sporophytic tissues comprising the rest of the plant. Manipulation of auxin responses or synthesis induces switching of gametic and nongametic cell identities and specialized nonreproductive cells to exhibit attributes presumptively lost during angiosperm evolution. These findings may account for the unique egg cell specification characteristic of angiosperms and the formation of seeds with single diploid embryos while containing endosperm that can have variable numbers of parental haploid genomes.
authors.affiliation: Department of Plant Biology, University of California, Davis, CA 95616, USA.
authors.forename: Gabriela C
authors.initials: GC
authors.lastname: Pagnussat
authors.forename: Monica
authors.initials: M
authors.lastname: Alandete-Saez
authors.forename: John L
authors.initials: JL
authors.lastname: Bowman
authors.forename: Venkatesan
authors.initials: V
authors.lastname: Sundaresan
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D005075:Biological Evolution; D015536:Down-Regulation; D035264:Flowers / Q000166:cytology* / Q000254:growth & development / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005854:Germ Cells / Q000166:cytology* / Q000254:growth & development / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D035683:MicroRNAs; D008938:Mitosis; D008954:Models, Biological; D010105:Oxygenases / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012639:Seeds / Q000166:cytology; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D026901:Membrane Transport Proteins; D035683:MicroRNAs; C116363:PIN1 protein, Arabidopsis; D011993:Recombinant Fusion Proteins; D010105:Oxygenases; C422746:YUC protein, Arabidopsis