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Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

Bukhari, Ghadeer [1], Zhang, Jingbo [2], Zhang, Wenheng [3].

Differential transcriptome analyses revealed genetic basis of zygomorphic corollas associated with bee and hummingbird pollination syndromes in Schizanthus (Solanaceae).

Schizanthus (Solanaceae) contains 12 species distributed mainly in Chile. The strongly zygomorphic flowers of Schizanthus are adapted to pollination by bees, hummingbirds and moths. Flowers of Schizanthus share fused petals that form a tube at the base of the corolla, two functional stamens located laterally and a single ventral and two dorsal stamens that are aborted. Species of Schizanthus with specific pollination syndromes also exhibit associated floral characteristics, as seen in the bee-pollinated Schizanthus pinnatus Ruiz & Pav. and the hummingbird-pollinated Schizanthus grahamii Gillies. Although both species have bright color patterns on the single dorsal petal and fringed lateral petals, the fused ventral petals distinctly differ between the two species. The two fused ventral petals of the bee-pollinated S. pinnatus form a long, lobed keel that encloses the two functional stamens. At maturity, the ventral keel of S. pinnatus has a mechanism that releases the stamens to explosively discharge pollen onto the body of the bee when it lands. In contrast, the hummingbird-pollinated S. grahamii has a smaller keel and shorter filaments on the two functional stamens located in the throat of the corolla tube. When hummingbirds drink nectar from the corolla, pollen coats the base of their beak. Here, we investigated the genetic basis of the distinct zygomorphic corollas in S. pinnatus and S. grahamii using differential gene expression profiles by sequencing the RNA transcriptomes. We identified genes that were differentially expressed in the ventral keels between the two species. For example, we found that none of the members of the TCP gene family were differentially expressed between the dorsal and ventral petals in S. grahamii, but several TCP genes were expressed at a higher level in the ventral keel of S. pinnatus. Furthermore, we discussed the implications of differentially expressed genes across the plane of floral symmetry and their potential role in the development of floral morphology associated with distinct pollination syndromes.

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1 - Virginia Commonwealth University, 1000 W Cary Street, Richmond, VA, 23284.0, United States
2 - Department Of Biology, Virginia Commonwealth University, 1000 West Cary Street, Life Science Building 336, Richmond, VA, 23284, United States
3 - Virginia Commonwealth University, Department Of Biology, 1000 W Cary Street, Richmond, VA, 23284, United States

Next generation sequencing
Schizanthus pinnatus
Schizanthus grahamii
Floral zygomorphy
Explosive pollen release
pollination syndrome
TCP gene family.

Presentation Type: Oral Paper
Session: 20, Evolutionary Developmental Biology (Evo-Devo) I
Location: 113/Mayo Civic Center
Date: Tuesday, July 24th, 2018
Time: 8:45 AM
Number: 20004
Abstract ID:824
Candidate for Awards:Katherine Esau Award

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