Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

Tong, Jingjing [1], Knox, Eric [2], Morden, Clifford [3], Cellinese, Nico [4], Howarth, Dianella [5].

Duplication and expression of CYCLOIDEA-like genes in Campanulaceae.

Shifts between radially symmetrical flowers and bilaterally symmetrical (zygomorphic) flowers occur many times independently in the diversification of flowering plants. Evidence from across angiosperms indicates that CYCLOIDEA-like (CYC) genes, which belong to the TCP gene family, play an important role in dorsal specific identity in bilaterally symmetrical flowers. In the core eudicots, two duplications have led to three clades of CYC-like genes: CYC1, CYC2 and CYC3. We focus on the evolution of CYC-like genes in the Campanulaceae, which is a large and world-wide eudicot group, with multiple symmetrical floral forms. We identified all three CamCYC paralogs from across Campanulaceae. We show that gene duplication is most common in CamCYC2, specifically in the bilaterally symmetric Lobelioideae. Duplication in CYC2 genes in bilaterally symmetrical groups has been common in core eudicots. Therefore, duplication of CamCYC2 genes with Lobelioideae is in line with hypotheses of CYC2-like gene function. However, in bilaterally symmetrical Cyphioideae, we detected CamCYC3 genes, but no CamCYC2 genes in this clade, suggesting that CamCYC3 genes might be involved in the development of bilaterally symmetrical flowers in this clade, instead of CamCYC2. We additionally highlight common patterns of duplication in CamCYC1, in which previous studies have suggested that core eudicot CYC1-like genes likely function in inflorescence development and plant branching, and are not commonly directly involved in flower morphological development. To examine how tightly correlated the expression pattern of the CYC-like genes is with changes in flower morphology, we utilized qRT-PCR to determine the CamCYC2 gene expression pattern in three species of bilaterally symmetrical Lobelioideae. The expression patterns of CamCYC2 genes coincided with previous studies in core eudicots species with bilateral symmetrical flowers. However, because Lobelioideae have resupinate (turned 180 degrees) flowers, both CamCYC2A and CamCYC2B are highly expressed in the ventral petals, which correspond to the adaxial side of the flower, suggesting conservation of dorsal identity in upside down flower. Additionally, individual copies of CamCYC2 genes show slightly different expression levels in different petals, suggesting possible subfunctionalization between these copies.

1 - St. John's University, Biological Sciences, 8000 Utopia Pkwy, Jamaica, NY, 11439, United States
2 - Indiana University, Department Of Biology, Bloomington, IN, 47405.0, United States
3 - University Of Hawaii, Department Of Botany, 3190 Maile Way, Honolulu, HI, 96822, United States
4 - University Of Florida, FLORIDA MUSEUM OF NAT. HISTORY, 1659 Museum Rd., 354 Dickinson Hall, Gainesville, FL, 32611, United States
5 - St. John's University, Department Of Biological Sciences, St. Albert Hall Rm 257, 8000 Utopia Pkwy, Jamiaca, NY, 11439, United States

Keywords:
Gene Expression
Campanulaceae
CYCLOIDEA
gene phylogeny
flower symmetry
flower morphology.

Presentation Type: Oral Paper
Session: EVDV1, Evolutionary Developmental Biology (Evo-Devo)
Location: Tucson E/Starr Pass
Date: Monday, July 29th, 2019
Time: 4:15 PM
Number: EVDV1011
Abstract ID:461
Candidate for Awards:Katherine Esau Award