Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

Leung, Wing-Sze [1], Arias, Tatiana [1], Kim, Sangtae [2], Lim, Wallace Boon Leong  [1], Saunders, Richard M.K. [1].

The Evolution of Differentiated Perianth in Early-Divergent Angiosperms: Floral Transcriptomics in Desmos chinensis (Annonaceae) using RNA-seq Analysis.

Flowers of most Annonaceae species have differentiated sepals and petals, in contrast to gradual transitioning of flower structures observed in most other groups of early-divergent angiosperms. This dipartite perianth is hypothesized to have evolved independently from that in eudicots. Differentiation of sepals and inner and outer petals have resulted in extensive morphological diversity within the family, apparent in different types of pollination chambers and various degrees of perianth fusion. Little is known about the genetic control of floral development in early-divergent angiosperms with a differentiated perianth like Annonaceae. Previous studies suggest that Asimina longifolia (Annonaceae) B-class (AP3 and PI homologs) MADS-box homeotic genes expression was not observed in sepals, but was detected in petals and stamens as in Arabidopsis thaliana. Most other early-divergent angiosperms with gradual transitioning of flower structures show a fading expression pattern of MADS-box genes. A complete analysis of all genes involved in floral development and their duplicates still awaits elucidation. Here we ask: What genes are controlling the floral organ identity and what genes are involved in the diversification of flowers in Annonaceae? High throughput RNA-seq technology offers a unique opportunity to investigate gene expression pattern in species lacking an available reference genome. The main focus of this study is to identify genes responsible for floral development and their expression patterns in Desmos chinensis. This species is a common Annonaceae in Hong Kong with a typical floral morphology for the family, comprising three differentiated perianth whorls and a basally constricted pollination chamber. Transcriptomes of floral organs of developing floral buds, flowers at anthesis, and young leaves will be sequenced using high-throughput Illumina sequencing platform. Multiplexing experimental design will allow separation of data by organ and developmental stage for comparison and differential expression analysis. Paired-end reads for de novo assembly and gene annotation will be generated. The assembled transcripts will then be used as a reference for subsequent differential expression studies. Validation of target genes expression patterns will be done using q-RT-PCR with three replicates. Expression pattern of target genes will then be compared with that in eudicots in order to understand the convergent evolution of dipartite perianth in Annonaceae. Findings of this study will also be a stepping-stone for further investigation of the molecular control underlying the diversity of floral morphology in this family.

1 - The University of Hong Kong, School of Biological Sciences, Hong Kong, China
2 - Sungshin Women's University, Department of Biology, Seoul 136-742, Rep. of Korea

Keywords:
Annonaceae
early-divergent angiosperms
perianth evolution
RNASeq
transcriptomics.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Eyrie/Boise Centre
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PEV003
Abstract ID:208
Candidate for Awards:None