Abstract Detail

Systematics Section/ASPT

Rodrigues Vaz, Carlos [1], Plunkett, Gregory [2], Lowry, Porter P. [3].

The utility of two WRKY transcription-factor genes to explore species-level relationships in Neotropical Schefflera (Araliaceae).

The systematics of Araliaceae (the ginseng family) has greatly evolved during the past two decades, and the polyphyly of its largest genus, Schefflera, has been one of the most significant findings. Schefflera comprises five geographically structured clades (Asian Schefflera, Neotropical Schefflera, Melanesian Schefflera, African-Malagasy Schefflera and Schefflera s. str.). Of these, Neotropical Schefflera comprises 205 described species and ~201 species awaiting formal description. Based on both morphology and geography, five subgroupings of Neotropical Schefflera have been recognized (Cephalopanax, Cotylanthes, Crepinella, Didymopanax and Sciodaphyllum). A preliminary study of the Neotropical and Asian clades of Schefflera has been completed based on six molecular markers (4 plastid and 2 nuclear spacers) and ~250 samples, but more rapidly evolving markers are needed to resolve relationships at finer scales (e.g., among closely related species). The WRKY family of nuclear transcription factors has been successfully used to resolve species-level relationships in other slowly evolving, woody taxa, such as Malvaceae and Arecaceae. In those families, several WRKY genes were shown to be single copy, but our preliminary data suggest multiple copies for at least two genes, WRKY1 and WRKY4. This finding may be explained in part by whole genome duplications through polyploidy, which is common among the members of the Asian Palmate clade of Araliaceae, to which both Asian and Neotropical Schefflera belong. To date, we have identified at least four copies of WRKY1 in Neotropical Schefflera, and three copies of WRKY4. Preliminary phylogenetic analyses based on these sequences appear to confirm the monophyly of the Crepinella, Didymopanax and Sciodaphyllum subgroups, and the sister-group relationship between Crepinella and Didymopanax.

Broader Impacts:

1 - The New York Botanical Garden, Cullman Program for Molecular Systematics, 2900 Southern Boulevard, Bronx, NY, 10458-5126, USA
2 - New York Botanical Garden, Cullman Program For Molecular Systematics, 2900 Southern Blvd., Bronx, NY, 10458-5126, USA
3 - Missouri Botanical Garden, P.O. Box 299, Saint Louis, MO, 63166-0299, USA

Keywords:
Schefflera 
Araliaceae
WRKY.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:30 PM
Number: PSY055
Abstract ID:653
Candidate for Awards:None