Systematics Section / ASPT
Kocyan, Alexander , Zhang, Li-Bing , Renner, Susanne S. .
Towards a densely sampled phylogeny of Cucurbitaceae worldwide.
Based on an analysis of nuclear, mitochondrial, and plastid sequences, Cucurbitaceae are sister to all other families of core-Cucurbitales (Zhang, Koycan, Renner, and Simmons, this meeting). To investigate the mating system evolution and biogeographic history of Cucurbitaceae, we have sequenced 100+ species, especially generic and tribal types, from 70 of the family’s currently recognized 120 genera (Jeffrey, 1990) for the genes matK and rbcL, the rpl20-rps12 intron and the trnL intron and spacer. The combined data show that the large subfamily Cucurbitoideae of worldwide distribution is monophyletic, and that the African, Madagascan, Indian, and Chinese (AMIC) genera of the smaller subfamily Zanonioideae are its sister clade. Unfortunately, the six New World genera of Zanonioideae have not been sampled. Deeper relationships in the family are not yet clear, but the data show that Cucurbiteae (7 of 13 genera sampled) and Sicyeae (10 of 16 gen.), both confined to the Americas, are monophyletic, while the AMIC genera of Benincaseae (13 of 18 gen. sampled), Melothrieae (22 of 34 gen.), and Trichosantheae (6 of 11 gen.) are interspersed with each other, with at least two clades of American genera embedded among them. Another AMIC tribe, Joliffieae (3 of 5 gen. sampled) and the monogeneric Chinese/Japanese Schizopeponeae form a basal grade, followed by a long-branch clade of West-Eurasian Bryonia and Ecballium. The so-far unplaced Madagascan genus Odosicyos falls in the Joliffieae grade. If these relationships hold up with the ongoing addition of further data, they imply that multiple independent lineages of Cucurbitaceae reached the New World at very different times during the distant and recent past. As expected from ecological and physiological studies, Cucurbitaceae appear to switch readily between monoecy and dioecy.
Cucurbitaceae phylogeny based on four plastid loci
1 - Colorado State University, Department of Biology, Fort Collins, Colorado, 80523-1878, U.S.A.
2 - University of Missouri-St. Louis, Biology, 8001 Natural Bridge Road, St. Louis, Missouri, 631321, USA
3 - Ludwig-Maximilians Universitaet Muenchen, Faculty of Biology, Munich, D-80638
Presentation Type: Poster
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM