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Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

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

Molecular evolution of CYC2-like genes in the Solanaceae family.

Gene duplications provide an essential source of genetic material that can lead to key phenotypic innovations. In core eudicots, floral symmetry shifts from ancestral actinomorphy to zygomorphy are usually associated with gene duplications and functional divergence of CYCLOIDEA2-like (CYC2-like) genes, which belong to the CYC/TB1 clade of the TCP gene family. The Solanaceae exhibit great diversity of floral symmetry, but it is unclear how CYC2-like genes have evolved and functionally diversified in the family. We carried out a phylogentic study with sequences mined from published genome and transcriptiome databases in addition to our own cloned sequencing data to determine the evoluiton of CYC2-like genes in Solanaceae. We investigated the phylogenetic relationships of CYC/TB1-like genes in Solanum lycopersicum, Nicotiana tomentosiformis, and Schizanthus pinnatus to cover both the morphological and phylogenetic diversity of the Solanaceae using Arabidopsis thaliana as the outgroup. We reconstructed three subclades (CYC1, CYC2, and CYC3) of the CYC/TB1 clade previously identified in core eudicots. Moreover, all three species from the Solanaceae possess two copies in each of these three subclades, which suggests that a possible genome-wide duplication event predating the diversification of Solanaceae may account for the origin of these paralogs. We also isolated CYC2-like genes from all major lineages of Solanaceae. Based on the sequence structure, we found two sequence types of CYC2-like genes, CYC2-ECE and CYC2-NEC. The CYC2-ECE copy has the typical ECE domain, but the CYC2-NEC copy is either missing or possesses a highly modified ECE domain. For the CYC2-NEC copy, the TCP basic region lacks a portion of the conserved N-terminal region and the R domain is less conserved compared with the CYC2-ECE copy in some species. The gene genealogy showed that each CYC2-like paralog mirrors the phylogenetic tree of the Solanaceae, which indicates that a gene duplication event predated the origin of the family. The molecular evolution analyses indicated that both CYC2-NEC and CYC2-ECE are under purifying selection, which suggests both copies are functional in Solanaceae. These results coincide with our gene expression and function studies, which indicated that these CYC2-like paralogs played important roles in stamen development in Solanaceae.

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

TCP gene family
CYC/TB1 clade
CYC2-like genes
gene duplication
whole-genome and transcriptome data.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PEV007
Abstract ID:967
Candidate for Awards:None

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