| Abstract Detail
Evolutionary Developmental Biology (Evo-Devo) Chang, Tien-Hao [1], Hu, Jer-Ming [2]. Petaloidy and floral organ identity genes in Hydrangea chinensis (Hydrangeaceae). The inflorescence of the plants in the family Hydrangeaceae is often aggregated as a pseudanthium, which contains enlarged sepals on peripheral flowers of the inflorescence. The flowers with these petaloid sepals are generally sterile and may play important roles in attracting pollinators. Hydrangea chinensis was used to examine the underlying mechanism of the petaloidy formation. The adaxial epidermal cells of enlarged sepals are conical shape and the epidermal surfaces of cells on examed floral parts all have cuticular striation. One A-class (HycFL), three B-class (HycPI, HycAP3, HycTM6), one C-class (HycAG) and one E-class (HycMADS1) floral homeotic genes were identified based on their conserved C-terminal motifs and the results from phylogenetic analysis.
RT-PCR results show that the A class homolog HycFL has ubiquitous expression in floral parts, but higher in enlarged sepals and carpels. The B-class homolog HycAP3 is expressed in petals, stamens, stigmas and lower part of carpels, which is fused to part of normal sepals. In contrast, HycPI is highly expressed in petals and stamens, and weakly in lower part of carpels. The expression of HycTM6, another B-class homolog, can be detected in all floral parts. The C-class gene homolog, HycAG, is expressed in the inner three whorls of flowers but the expression is higher in stamens and carpels. The E-class gene homolog HycMADS1 is expressed in all floral parts. We have also successfully cloned HycMIXTA, a homolog of MIXTA, which encodes a transcription factor required for the formation of conical cells in Antirrhinum majus. The RT-PCR result shows that HycMIXTA is highly expressed in enlarged sepals and lower in normal sepals and petals. Since HycFL, HycTM6, HycMADS1 and HycMIXTA are all expressed in enlarged sepals, they are likely involve in the formation of enlarged sepals of Hydrangea chinensis.
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1 - National Taiwan University, Institute of Ecology and Evolutionary Biology, Rm. 1227, Life Science Building, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei, 10617, Taiwan (R.O.C.)
2 - National Taiwan University, Institute of Ecology and Evolutionary Biology, Rm1227, Life Science Building, 1 Roosevelt Road, Sect.4, Taipei, 106, Taiwan
Keywords:
MADS-box gene
Hydrangea
MIXTA
petaloid.
Presentation Type: Poster:Posters for Topics
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P70004
Abstract ID:1566 |
