Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

Zhang, Jingbo [1], Zhang, Wenheng [1].

Evolution, expression, and function of CYC2-like genes in Solanaceae.

Although most flowers in the Solanaceae are viewed as being radially symmetric, zygomorphic androecia, which develop through abortion and modification of the stamens, are quite common in this group. In core eudicots, CYCLOIDEA-like (CYC2-like) genes, known to control floral zygomorphic development, are responsible for arresting stamen development in Asterales, Dipsacales, and Lamiales. It has remained uncertain, however, whether this genetic mechanism is also deployed to control development of zygomorphic androecia in Solanaceae. We investigated the evolution, expression and function of CYC2-like genes in Solanaceae and found two major copies of CYC2-like genes in the major lineages of the family, CYC2-ECE and CYC2-NEC. They originated through gene duplication predating the origin of the family. Differential expressions of these CYC2 paralogs were examined in Schizanthus pinnatus, which displays strong floral zygomorphy in the corolla and androecium, and in Solanum lycopersicum (tomato), which produces actinomrophic flowers. Our real-time PCR indicated that the CYC2-ECE copy is highly expressed during an early stage of flower development in both So. lycopersicum and Sc. pinnatus. The CYC2-NEC copy exhibits continuous expression during floral development, with relatively high expression in the early and late stages in Sc. pinnatus, but early expression was absent in So. lycopersicum. Our in situ data for Sc. pinnatus indicates that the CYC2-ECE copy is initially expressed in the primordia of the two lateral stamens and the three staminodes (two dorsal and one ventral), but the expression is mainly maintained in the two functional stamens at a later stage of floral development. In contrast, the CYC2-NEC copy has a broader pattern of expression compared to the CYC2-ECE in Sc. pinnatus, which was detected in the stamen, staminode, petal, and carpel regions. Silencing of the CYC2-ECE in Schizanthus by using the virus-induced gene silencing (VIGS) approach resulted in abortion of two functional stamens, which demonstrates that the CYC2-ECE gene likely promotes the development of the functional stamens. Ongoing VIGS experiments for silencing the CYC2-NEC and the double silencing of both CYC2-like paralogs in Sc. pinnatus will further characterize the function and the role of CYC2 genes in floral development in Solanaceae.

1 - Virginia Commonwealth University, Department of Biology, 1000 W Cary Street, Richmond, VA, 23284, USA

Keywords:
abortion and modification of stamens
CYC2-like genes
Development
Floral Symmetry
gene expression
gene function
Phylogeny
solanaceae.

Presentation Type: Oral Paper:Papers for Topics
Session: 26
Location: Hall B/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 8:00 AM
Number: 26001
Abstract ID:870
Candidate for Awards:None