Molecular Phylogeny of the Goldenasters, Subtribe Chrysopsidinae (Asteraceae, Astereae), Based on Nuclear Ribosomal and Chloroplast Sequence Data
Subtribe Chrysopsidinae, also known as Goldenasters, is a group of wildflowers distributed from North to South America and inclusive of eight genera sensu Semple. Historically, phylogenetic inference of the Chrysopsidinae has been based on morphological criteria, resulting in the proposition of multiple classifications by different researchers. Some studies based on chloroplast DNA restriction site data have been inconclusive in the resolution of relationships among all the genera and species in this group. Furthermore, no single study has sampled among all genera or all known species of the Chrysopsidinae for assessment of evolutionary relationships. In this study, we estimated phylogenies based on molecular data from ETS and ITS, nuclear ribosomal DNA, and ycf1 and psbA-trnH, chloroplast DNA for all known genera of the Chrysopsidinae. We used these phylogenies as the basis for addressing questions related to subtribal and generic monophyly, the relationship of Central and South American genera, Osbertia, Tomentaurum, and Noticastrum to North American genera, morphological trait evolution and the frequency of convergence among morphological features commonly used to delimit species boundaries. Results from analysis of independent and combined data support the monophyly of the Chrysopsidinae. We observe generic resolution among members of the Chrysopsidinae, and some sectional resolution within the genus Heterotheca. However, like for other groups of tribe Astereae, the search continues for genetic markers that are variable enough to resolve relationships among species.
Towson University
140 • Timothy A. Hammer1, Robert W. Davis2, Kevin R. Thiele2
A Molecular Framework Phylogeny for Ptilotus R.Br. (Amaranthaceae)
Ptilotus R.Br. (Amaranthaceae) comprises over 100 species, which are endemic to Australia except for one species (P. conicus R.Br.) that has a distribution extending to Timor and adjacent islands. The center of diversity for the genus is the arid Eremean Province of Western Australia, with smaller numbers of species found in open mesic temperate areas and wet-dry tropics. Family-wide studies have placed Ptilotus within the monophyletic Aervoid clade, consisting of Aerva Forssk. (16 spp.), Nothosaerva brachiata L. and Ptilotus. A lack of extensive sampling within this clade has made it difficult to discern the relationships between the genera. To date, no robust infrageneric classification has been proposed for Ptilotus, in part due to the lack of consistent morphological differences between the major groups of taxa. ITS nrDNA and matK cpDNA were amplified by PCR and sequenced from all major informally recognized groups within Ptilotus and several outgroup taxa. Sequences were edited with Geneious 6.0, aligned using webPRANK, and analyzed using maximum parsimony, maximum likelihood and Bayesian inference. The current study provides the first framework phylogeny for Ptilotus, provides evidence for the monophyly of the genus, clarifies phylogenetic relationships within the genus and the Aervoids, allows assessment of congruence of robust clades with morphological variation, and identifies characters to aid in an infrageneric classification. This study will provide the framework for future studies into character evolution, physiology and ecology in the genus; in addition, Ptilotus is likely to provide useful insights into the evolution and adaptation of the arid Australian biota.
1Dept of Biological Sciences, Old Dominion University, Norfolk, VA; 2 Western Australian Herbarium, Dept of Parks and Wildlife, WA, Australia
Edible Lansium domesticum, Meliaceae originated in Malaysia. It grows wild and has been cultivated in many places around Southeast Asia. Little has been studied about the origin of this type of L. domesticum. The morphological traits and genetic diversity were examined from major sites in Thailand. The results indicate that the overall features of this type of L. domesticum were almost identical except for a few fruit characteristics. The single strand conformational polymorphism (SSCP) technique was used to analyze the relationship among varieties of L. domesticum. Three specific primers of glyceraldehyde 3 phosphate dehydrogenase (G3PDH), abscissic acid insensitive3 (ABI3), and isocitrate dehydrogenase (IDH) show high polymorphism. The results also indicate that edible L. domesticum varieties are heterozygous and triploid. The chloroplast molecular markers show that most edible L. domesticum varieties share the same maternal plant. The paternal side of this group has not yet been established. Future studies can examine more levels of genetic diversity by collecting more plant samples from similar or closely related species around the Indo-Malaysian Peninsula.
1 Biology Dept, Winthrop University, Rock Hill, SC; 2 NSTDA/BIOTEC Center of Agricultural Biotechnology, Kasetsart University, Nakhon Pathom, Thailand
