Create your own conference schedule! Click here for full instructions

Abstract Detail



Evolutionary Developmental Biology (Evo-Devo)

Ma, Qing [1], Liu, Xiang [1], Franks, Robert [1], Zhang, Jian [3], Xie, Deyu [4], Xiang, Jenny [4].

Testing the hypothesis of CorTFL1 expression in Cornus inflorescence evolution - comparative qRT-PCR, in-situ & nbs.

TFL1 is known to be a key regulator that controls flowering and inflorescence development of Arabidopsis thaliana and involves maintenance of the meristem shoot. Its function is in contrast with AP1 and LFY that promote floral meristem and floral organ development. The expression levels of these genes relative to one another determine the meristem to form a shoot (continue to grow and branch) or floral structure (terminate growth). It was hypothesized that during inflorescence development, the relative time duration of TFL1 expression at a certain threshold (relative to LFY/AP1) determines the architecture of the inflorescence. Therefore, TFL1 was proposed to play a major role in the evolution of inflorescence architecture in angiosperms. We test this hypothesis using the dogwood genus (Cornus L.) where differences in inflorescence architecture have evolved among closely related lineages, from condensed head-like to large and elongated forms. If TFL1 expression plays a role in the divergence of the inflorescence forms in Cornus, we expect to observe high expression of the gene in inflorescence meristem (IM), inflorescence branch meristems (IM), but a greater level in the large and elongated inflorescences, followed by significantly down regulation to weak or no expression of the gene in floral meristems in all species. We used qRT-PCR to compare expression levels of TFL1 at different developmental stages among six species and examined the spatial expression pattern in four species using RNA in-situ hybridization. Furthermore, we over expressed CorTFL1 in the tfl1 mutant and wild-type Arabidopsis plants, but down regulated its expression in Cornus canadensis. Our results from genetic transformation confirmed the function of CorTFL1 in repressing flowering in Arabidopsis and in Cornus (rescued phenotype of Arabidopsis mutant to the extent of wild plants) and accelerated flowering time in C. canadensis). Results from qRT-PCR from one set of biological duplicate of six species and in-situ hybridization from two species are largely consistent with the expectation. The only potential exception was observed for C. macrophylla that produces large, elongated inflorescences where qRT-PCR analysis indicates TFL1 is also expressed highly in bud samples representing floral early organogenesis stage. It is possible that the samples contained some buds of earlier development. The combined evidence obtained so far support the hypothesis that changes in TFL1 expression pattern during the inflorescence development may play a role in the molecular mechanisms controlling the divergence of inflorescence architecture in Cornus. This finding will be confirmed with additional data collecting.


Log in to add this item to your schedule

1 - North Carolina State University, Department Of Plant And Microbial Biology, Gardner Hall 2115, Campus Box 7612, Raleigh, NC, 27695, United States
2 - North Carolina State University, Department Of Plant And Microbial Biology, Gardner Hall 2115, Campus Box 7612, Raleigh, NC, 27695, United States
3 - Institute of botany, Chinese academy of sciences, Plant Systematics and Evolution, No. 20, Xiangshannanxin Village, Haidian District, Beijing, 100093, CN
4 - North Carolina State University, Department Of Plant And Microbial Biology, Gardner Hall 2115, Campus Box 7612, Raleigh, NC, 27695, USA

Keywords:
TFL1
inflorescenceevolution
qRT-PCR
in-situ hybridization
function.

Presentation Type: Oral Paper:Papers for Topics
Session: 46
Location: Payette/Boise Centre
Date: Wednesday, July 30th, 2014
Time: 4:15 PM
Number: 46003
Abstract ID:421
Candidate for Awards:None


Copyright 2000-2013, Botanical Society of America. All rights reserved