Evolutionary Developmental Biology (Evo-Devo)
Landis, Jacob , O'Toole, Rebecca , Ventura, Kayla , Soltis, Douglas , Soltis, Pamela S. .
Investigating the genetic underpinnings of corolla cell size and shape differences in Saltugilia (Polemoniaceae).
Corolla length has been shown to have strong implications for pollinator success, yet the phenotypic and genetic basis of corolla elongation is not well known. This is largely due to a lack of good candidate genes for potential genetic exploration and, more importantly, a lack of functional work for the few candidate genes available. In this study, we investigate both the cellular phenotypic differences in corolla length as well as the genetic control of this trait in Saltugilia (Polemoniaceae). The taxa in this group have different known pollinators – bee, bee fly, and hummingbird pollination, as well as selfing mating systems – and exhibit a range of sizes from 8 mm to 25 mm. However, there is no closely related model system that could shed light on the developmental aspects of flowers in Polemoniaceae, so de novo approaches were pursued. Flowers of each of the five species were collected from multiple individuals during four stages of flower development in order to determine if cell number or cell size was the more important factor in flower size. Using optical sectioning, quantitative differences in cell number and cell size were identified for all five taxa, each with a unique pollinator type and varying sizes of flowers. In all taxa examined, the fully mature flowers contain a cell type not seen in developing flowers: elongated jigsaw cells similar to those in sepals and leaves. To help identify candidate genes, transcriptomes were generated for two individuals of the species of Saltugilia with the smallest (S. australis) and largest (S. splendens subsp. grantii) flowers across the same four developmental stages visualized. De novo assemblies were performed, and analyses were conducted to identify genes that are turned on/off during different stages, as well as those that were shared and unique between the two species. As well as determining presence/absence, we also identified those genes appearing to be under positive selection by comparing synonymous and nonsynonymous substitution rates. Using gene function databases, we focused on candidate genes that have been shown to have functions in organ size development in model species. This approach has provided a foundation for future investigation of gene expression and function of genes that may control flower size in Saltugilia.
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1 - University Of Florida, Dept Of Biology, Florida Museum Of Natural History - Dickinson Hall, Museum Road And Newell Drive, Gainesville, FL, 32611, USA
2 - University of Florida, Florida Museum of Natural History, 1659 Museum Road, Dickinson Hall, Gainesville, FL, 32611, USA
3 - University Of Florida, Florida Museum Of Natural History, PO Box 117800, Gainesville, FL, 32611-7800, USA, 352/273-1964
Presentation Type: Oral Paper:Papers for Topics
Location: Hall B/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 10:15 AM
Candidate for Awards:Katherine Esau Award