Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

Zhong, Jinshun [1], Powell, Sarah [2], Powers, Beck [2], Preston, Jill [3].

Functional evolution of NAC-domain transcription factors is implicated in the evolution of petal fusion.

Sympetalous (fused) corollas have been considered evolutionary innovations that enhance pollination efficiency, hence promoting speciation. Sympetaly has evolved multiple times independently during the diversification of angiosperms. However, one of the most striking plant lineages with ancestrally fused petals is the asterid clade of core eudicots that comprises one fourth of angiosperm diversity. Although the genetic basis of organ boundary patterning is well defined in the free-petaled rosid species Arabidopsis thaliana (Brassicaceae), it is unknown if and how this pathway has been modified to affect fused asterid petals. We hypothesize that the novel acquisition of petal fusion has occurred through changes in the expression or function of organ boundary genes, such as the NAC-domain transcription factors CUP-SHAPED COTYLEDON 1 (CUC1), CUC2, and CUC3. To test this hypothesis we characterized the expression and function of petunia NAC-domain genes with homology to the Arabidopsis CUC genes using qPCR, in situ hybridization, and virus-induced gene silencing. Our data support a context-specific shift in function for NAM/CUC1/CUC2 and NH16/CUC3 genes between Arabidopsis and petunia, with the petunia genes uniquely promoting fusion in the petals, but retaining the conserved function of repressing fusion in sepals, stamens, and stamens-carpels.

1 - Department Of Biology, 323 Jeffords Hall, 63 Carrigan Drive, Burlington, VT, 05401, USA
2 - University of Vermont, Plant Biology, 111 Jeffords Hall, 63 Carrigan Drive, Burlington, VT, 05405, USA
3 - University of Vermont, Department of Plant Biology, 63 Carrigan Drive, 111 Jeffords Hall, Burlington, VT, 05405, USA

Keywords:
fused petals
organ boundary formation
Petunia
Virus-induced gene silencing.

Presentation Type: Oral Paper:Papers for Topics
Session: 26
Location: Hall B/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 8:15 AM
Number: 26002
Abstract ID:318
Candidate for Awards:None