Abstract Detail

Evolution, Development, and BSA Genetics of Floral Display - Form, Size, and Arrangement

Xiang, Qiu-Yun (Jenny) [1], Ma, Qin [2], Liu, Xiang [1], Franks, Robert [1].

A proposed TFL1-AP1-like gene-based model for the evolution of inflorescence architecture in Cornus L. (Cornaceae).

Inflorescence type is an important ecological trait affecting pollination rate, seed number, and dispersal ability. The role of the inflorescence in angiosperm evolution and diversification is clearly pivotal. However, the molecular mechanisms responsible for evolutionary modification of inflorescence architecture in non-model and natural groups are poorly known. TFL1, AP1, and LFY like genes are known to be key regulators of inflorescence development. However, whether evolutionary modifications of inflorescence morphology are results of pattern shifts in their expression remains to be tested. We compared the spatiotemporal expression patterns of CorTFL1, CorAP1, and CorLFY in six closely related Cornus species displaying variation in form and size of closed inflorescences, from elongated paniculate/corymbose forms to umbels and heads. We conducted character mapping and correlation analyses to identify evolutionary changes co-occurring in gene expression and related inflorescence morphology. We found a complementary pattern between CorTFL1 and CorAP1 expression and a strong correlation between CorTFL1 expression and the branch index of inflorescence types. Evolutionary changes in CorTFL1 and CorAP1 expression co-occurred on the phylogeny with the morphological changes underpinning inflorescence divergence. The clear correlation between the expressions of CorTFL1 and CorAP1 and the inflorescence architecture in the Cornus system with closed inflorescences suggested a role of altered CorTFL1 and CorAP1 expression during evolutionary modifications of inflorescences in the genus, which may also applicable to other taxa. Evidence from functional analyses of CorTFL1 and CorAP1 using genetic transformation is congruent with their roles in regulating inflorescence development and structures. We propose that a TFL1-AP1-like gene-based model for the evolution of inflorescence architecture in Cornus, that may explain repeated evolution of closed umbels and heads from elongated determinate forms in angiosperms.

1 - North Carolina State University, Department of Plant and Microbial Biology, Gardner Hall 2115, Raleigh, NC, 27695-7612, United States
2 - Zhejiang University, 388 Yuhangtang Road, Hangzhou, 310058, P.R. China

Keywords:
Inflorescence architecture evolution
gene expression
character correlation
Gene regulation.

Presentation Type: Symposium Presentation
Session: SY05, Evolution, Development, and Genetics of Floral Display - Form, Size, and Arrangement
Location: Chatham Ballroom - B/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 11:15 AM
Number: SY05008
Abstract ID:568
Candidate for Awards:None