phylogeny of cucurbitales inferred from nine chloroplast
TRANSCRIPT
Phylogeny of Cucurbitales inferred from nine chloroplast, mitochondrial and nuclear loci
LI-BING ZHANG and SUSANNE S. RENNER. Department of Biology, University of Missouri-St. Louis, St. Louis, MO 63121. Email: [email protected]; [email protected]
Based on rbcL (Setoguchi et al. 1999; Schwarzbach & Ricklefs 2000), Cucurbitales comprise Anisophylleaceae, Begoniaceae, Coriariaceae, Corynocarpaceae, Cucurbitaceae, Datiscaceae, and Tetramelaceae. To further investigate the position of Anisophylleaceae and to approp- riately root a large molecular phylogeny of Cucurbitaceae, we are investigating family relationships in Cucurbitales. Previous molecular data have identified Fagales as the sister clade to Cucurbitales, but prior to our project, Anisophylleaceae had been weakly sampled and only sequenced for rbcL, which provided limited support for the monophyly of Cucurbitales. We have combined nuclear 18S, the chloroplast genes atpB, matK, ndhF, and rbcL, the trnL intron, the rpl20-rps12 and trnL-trnF spacers, and the mitochondrial nad1 b/c intron (together 9302 aligned bp) for 25 representatives of the ingroup families and two fagalean outgroups. Cucurbitales are strongly monophyletic, and Anisophylleaceae are sister to the remaining families, which form a trichotomy of (1) Cucurbitaceae, (2) Coriariaceae and Corynocarpaceae, and (3) Begoniaceae (Datiscaceae, Tetramelaceae). The relationship between the last three families has also been addressed with restriction site and ITS data (Rieseberg et al., 1992; Swensen et al., 1998),as well as flower morphology, which indicated a close relationship of Datiscaceae and Tetramelaceae. With the exception of a few Coriariaceae and Corynocarpaceae, Cucurbitales all have unisexual flowers, and plants are usually monoecious, with repeated shifts to dioecy in Begonia, Cucurbitaceae, Datisca cannabina, and Tetramelaceae. Because molecular data do not yet resolve family relationships in the Cucurbitales, it is unclear whether the few perfect- flowered Coriariaceae / Corynocarpaceae represent basal lines or reversals from unisexual to perfect flowers. The latter is exceedingly rare, and we are currently exploring additional DNA markers specifically to resolve their position in the order.
Anisophylleaceae
Photo: G. E. Schatz
Anisophyllea fallax�
Datiscaceae
Photo: P. Endress
Datisca cannabina
Tetramelaceae
Octomeles sumatrana
Photo: W. TakeuchiCoriariaceae
Coriaria myrtifolia
Photo: G. Gerlach & P. Endress
Corynocarpaceae
Photo: G. C. Linney
Corynocarpus laevigatus
Cucurbitaceae
Photo: P. Endress�
Marah fabaceus
Begoniaceae
Begonia evansii
Photo: B. Glick
96
Juglans nigra
Fagus grandifolia
Anisophyllea corneri
Anisophyllea obtusifolia
Anisophyllea fallax
Combretocarpus rotundatus
Begonia herbacea
Begonia oxyloba
Hillebrandia sandwicensis
Datisca glomerata
Datisca cannabina
Octomeles sumatrana
Tetrameles nudiflora
Coriaria ruscifolia
Coriaria sarmentosa
Corynocarpus laevigatus
Coccinia sessilifolia
Lagenaria brevifolia
Dendrosicyos socotranus
Gurania megistantha
Seyrigia humbertii
Ecballium elaterium
Marah macrocarpus
Schizopepon bryoniifolius
Gynostemma pentaphyllum
Neoalsomitra sarcophylla
Xerosicyos danguyi
50 changes
9495
100
100
100
100
100
100
100
100
100
100100
88
98
100
Anisophylleaceae
Begoniaceae
Datiscaceae
Tetramelaceae
Coriariaceae
Corynocarpaceae
Cucurbitaceae
100
(Single most parsimonious tree, CI = 0.72 RI =0.79 bootstraps at branches from 100 replicates)�