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Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

Bukhari, Ghadeer [1], Zhang, Wenheng [2].

Differential transcriptome analysis of floral zygomorphy development crucial to an explosive pollen release mechanism in Schizanthus (Solanaceae), the poor man’s orchid.

Recent advances in understanding the developmental genetics of floral zygomorphy indicate that repeated deployment of CYC2-like genes in the TCP gene family regulate floral zygomorphy in core eudicots. Schizanthus (Solanaceae) consists of 12 species distributed mainly in Chile. The butterfly-like flowers of Schizanthus are adapted to pollination by bees, hummingbirds, and moths. The pentapetalous Schizanthus flower consists of a single dorsal petal, two lateral petals, and two ventral petals. The petals are fused to form a tube at the base of the corolla to which the filaments of the stamens and staminodes are fused. There is one ventral and two dorsal aborted stamens, while the two functional stamens are located laterally. Floral morphology of Schizanthus is strongly associated with the pollination syndrome. We investigated the genetic basis of the explosive pollen release mechanism in the species of Schizanthus adapted to bee pollinators. The bee-pollinated species of Schizanthus have fringed dorsal and lateral petals displaying bright color patterns for attraction and two, fused ventral petals forming a lobed keel that encloses the two functional stamens. During floral development, the fused ventral petals increase in size in coordination with the development of the two functional stamens and the developing tension. At maturity, the flower releases the stamens to explosively discharge pollen onto the body of the bee once it lands on the ventral lobed petals. The floral morphology that has given rise to this explosive pollen release occurs uniquely in Schizanthus and depends on highly regulated development of floral zygomorphy. Our experiments indicated that CYC2 is radially expressed in the androecium and might not be involved in the development of floral zygomorphy in Schizanthus. We examined differential gene expression profiles across the zygomorphic corolla of Schizanthus × wisetonensis Low by sequencing the RNA transcriptome. We found that tissues of the ventral petals begin to differentiate and become rigid, in comparison with the soft tissue of the dorsal and lateral petals, after formation of the floral organs. This difference in development results in a natural boundary for us to easily separate the ventral petals from the other parts of the corolla. We report differential gene expression profiles in the ventral petals and in the dorsal plus lateral petals in this study.

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1 - Virginia Commonwealth University, Biology department, 1000 W Cary Street, Richmond, VA, 23284, USA
2 - Virginia Commonwealth University, Biology, 1000 West Cary Street, Richmond, VA, 23284, USA

Next generation sequencing
floral zygomorphy
Explosive pollen release
pollination syndrome.

Presentation Type: Poster
Session: P, Evolutionary Developmental Biology (Evo-Devo) Special Topic:Posters
Location: Exhibit Hall/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 5:30 PM This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PEV002
Abstract ID:478
Candidate for Awards:Katherine Esau Award

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