Abstract Detail

Systematics Section/ASPT

Molgo, Iwan [1], SOLTIS, PAMELA S. [2], Soltis, Douglas E. [3].

Exploring a polyploid complex in Callisia Loefl. section Cuthbertia (Commelinaceae).

Polyploidy is an important mechanism that generates plant diversity. A classic polyploid complex occurs in Callisia section Cuthbertia (Commelinaceae). Callisia graminea, C. rosea and C. ornata are closely related species endemic to the southeastern United States, ranging from southeastern Virginia to south Florida. Polyploidy in C. graminea was discovered 70 years ago, and the evolutionary relationships among the three ploidal levels (2x, 4x and 6x) are still unclear. The diploid and tetraploid entities are geographically isolated and distinct in morphology and cytology. The origin of tetraploid C. graminea is uncertain; autopolyploidy has been recorded in C. graminea but allopolyploidy derived from diploid C. graminea and diploid C. rosea cannot be excluded. Hexaploid C. graminea is restricted to Florida and South Carolina; either C. rosea or C. ornata could be a parent, with the other likely parent being tetraploid C. graminea. Cytotypes were collected throughout its range, and updated distribution maps have been compiled. The nuclear internal transcribed spacer (nrITS) region and several plastid markers have been explored for utility. The DNA sequences were tested for variation among samples of the three Callisia species and their putative polyploid derivatives. A combined analysis of the plastid data supports the monophyly of Callisia section Cuthbertia. Plastid data revealed variation among the tetraploid entities of C. graminea. The hexaploids were placed as sister taxa to diploid C. ornata and tetraploid C. graminea and are possibly a result of a hybridization event between C. ornata and tetraploid C. graminea. Sequencing of additional nuclear and plastid regions is being explored to further clarify relationships. This project is part of a larger study in which we will investigate gene flow and population structure in Callisia section Cuthbertia and examine phylogenetic relationships across all of Callisia.

1 - University Of Florida, Department Of Biology, 385 Dickinson Hall, P.O. Box 117800, Gainesville, FL, 32611-7800, USA
2 - University Of Florida, Florida Museum Of Natural History, PO BOX 117800, Gainesville, FL, 32611-7800, USA, 352/273-1964
3 - University of Florida, Florida Museum of Natural History, PO Box 117800, Gainesville, FL, 32611, USA

Keywords:
polyploidy
Commelinaceae
Southeastern United States
Cuthbertia
Roseling.

Presentation Type: Oral Paper:Papers for Sections
Session: 31
Location: Pines South/Boise Centre
Date: Tuesday, July 29th, 2014
Time: 5:00 PM
Number: 31013
Abstract ID:661
Candidate for Awards:None