Developmental and Structural Section
Povilus, Rebecca , Friedman, William .
Auxin Biosynthesis and Female Reproductive Development in Aquilegia.
Buried deeply within each angiosperm ovule is a haploid, egg-producing structure known as the female gametophyte. These structures consist of a specific arrangement of cell types along a longitudinal micropylar-chalazal axis, and it has been shown that auxin is essential to setting up this patterning. In Arabidopsis thaliana, local auxin synthesis at the micropylar end of a developing ovule results in establishment of gametic and essential accessory cell identity within the female gametophyte, whereas low auxin concentration at the chalazal end correlates to the formation of sterile cells (Pagnussat 2009). Whether our understanding of the molecular framework underlying this developmental process in a single, highly derived model organism can be extended to phylogenetically distant taxa with similar features, let alone be used to explain production of morphological diversity, remains unknown. Species in Aquilegia share the same type of female gametophyte as Arabidopsis thaliana (Mottier 1895) and, as part of the early diverging eudicot family Ranunculaceae, provide an excellent opportunity to address this question in an evolutionarily meaningful context.
In order to infer the dynamics of local auxin biosynthesis during ovule/female gametophyte development in Aquilegia, 1) I adapted whole mount confocal microscopy methods to study ovule and female gametophyte development in Aquilegia origami and, 2) I identified from within the genome of Aquilegia coerulea (http://www.phytozome.net) putative orthologs of gene families known from Arabidopsis thaliana to be involved in auxin biosynthesis(TAA1/TAR1, YUCCA) (Strepanova 2008, Zhao 2001). Each gene family contains multiple members in Aquilegia. Using semi-quantitative RT-PCR, I distinguish which copies are specific to early carpel and ovule development, and thus are good candidates for future analysis via mRNA in situ hybridization.
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1 - Harvard University, Organismic and Evolutionary Biology, 1300 Centre Street, Arnold Arboretum, Boston, MA, 02131, USA
Presentation Type: Poster:Posters for Sections
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM