Developmental and Structural Section
Sengupta, Aniket , Hileman, Lena .
Testing the role of bilateral flower symmetry genes in eudicot lineages with radial flowers.
Based on the number, position and shape of organs in the perianth and androecium, flowers can be radially symmetrical (actinomorphic; for example, roses) or bilaterally symmetrical (zygomorphic; for example, snapdragons). Bilateral flower symmetry has been acquired at least 46 times from radial symmetry during eudicot diversification. Surprisingly, all such independent acquisitions studied to date reveal that a CYCLOIDEA (CYC)-dependent developmental program specifies bilateral flower symmetry. An immediate question that arises from this result is why a similar genetic program was recruited extensively during independent transitions from radial to bilateral flower symmetry. Critical to addressing this question is understanding the role of the CYC-dependent flower symmetry program in angiosperm lineages that represent ancestral (plesiomorphic) radial symmetry. Therefore, we are investigating the expression and function of CYC-dependent pathway homologs in representative eudicot lineages with radial flowers, where radial flower symmetry is likely a plesiomorphic condition: Eschscholzia californica (California poppy), Dianthus caryophyllus (carnation), Kalanchoe laxiflora (milky widow’s thrill), Ipomoea lacunosa (pitted morning glory). To date, we have isolated CYC-like genes from our study species and determined orthology with CYC-like genes from species with bilateral flower symmetry. Previous work on expression and function of CYC homologs in species with bilateral flower symmetry provides a framework for testing two exclusive hypotheses for the role of CYC homologs in eudicot species with radial flower symmetry. 1) Where studied, CYC homolog expression in eudicot species with bilateral flower symmetry is dorsal (adaxial)-specific. Dorsal-specific expression of CYC-like genes in radially symmetrical ancestors could have pre-disposed these genes towards a recurrent function defining dorsal-specific development of bilaterally symmetrical flowers. Therefore, through gene expression studies we will test for conserved dorsal-specific regulation of CYC homologs in our study taxa. 2) A common function of CYC-like genes during development of radially symmetrical flowers could have pre-disposed the CYC-dependent genetic program to co-option for development of bilaterally symmetrical flowers. Therefore, with functional studies we will test for a conserved role of CYC homologs in our study taxa.
1 - University of Kansas, Ecology and Evolutionary Biology, 8003 Haworth Hall, 1200 Sunnyside Avenue, Lawrence, KS, 66045, USA
bilateral flower symmetry
radial flower symmetry
Presentation Type: Poster:Posters for Sections
Candidate for Awards:None