Systematics and taxonomy of Annonaceae

Research in the tropical plant family Annonaceae includes preparing a monography of the genus Annona L. and producing a nomenclatural and taxonomic index of the family. This is embedded within the global data collection effort of the Catalogue of Life.


Comparative phylogenetics in the N-Hemisphere polyploid complex of Achillea millefolium agg. (Asteraceae)

The greatest species diversity of yarrow and a wide range of diploids (2x) and various polyploids (4x, 6x, 8x) has developed in western Eurasia, where the group originated. A second phase of differentiation, with only a few 2x, 4x, 6x and 8x taxa, has occurred in temperate Asia. From there, the complex has finally expanded during a third, final phase of evolution into North America, where it has become established by only a single species but with highly diverse 4x and 6x populations in habitats from the sea shores to the highest mountains. International collaborations allow a continuation of these studies already started in the 1950s.


Phylogeny, Systematics and Taxonomy of Tillandsia, Vriesea, and Guzmania (Bromeliaceae)

These three largest genera of subfamily Tillandsioideae of Bromeliaceae (bromeliads; a.k.a. pineapple family) have been intensively studied in the past decades by our research group but their phylogenies and classifications are still insufficiently resolved. Increased taxon sampling and character evaluations are needed to obtain better resolution and deeper insights into the evolution of the numerous taxon groups within these genera. While molecular tools have quite rapidly developed during the past years and whole genome analyses can now be conducted at reasonable cost, morphological characters are still underexplored and are a major focus for the years to come.


Taxonomy of Gymnocalycium (Cactaceae)

The South American genus Gymnocalycium demonstrates how the sole use of morphological data in Cactaceae results in conflicts in assessing phylogeny, constructing a taxonomic system, and analyzing trends in the evolution of the genus. The results of the phylogenetic study confirm the monophyly of the genus, while supporting overall the available infrageneric classification based on seed morphology with some modifications. Analysis of morphological characters showed a tendency toward reduction of stem size, reduction in quantity and hardiness of spines, increment of seed size, development of napiform roots, and change from juicy and colorful fruits to dry and green fruits.


Relic genera and explosive evolution in Dipsacaceae (=Caprifoliaceae/Dipsacoideae)

Continuing detailed multidisciplinary studies on the family, it was possible to clearly document close relationships between two aberrant monotypic and obviously relic genera of the family: The annual herb Pterocephalidium diandrum from the western Mediterranean and the treelet Pterothamnus centennii from the mountains of Mozambique in southern Africa, classified as a new genus, and both were united as a new tribe, Pterocephalidieae. This contrasts strongly with the amazing evolutionary diversity within the genus Knautia in western Eurasia linked to dysploidy and polyploidy, which is now being revisited with DNA analytical methods in collaboration with other research groups.


Evolution in Gentianella (Gentianaceae)

For information, visit the project homepage: www.botanik.univie.ac.at/systematik/projects/Gentianella/


Evolution in Magnoliidae

We study the floral evolution in Magnoliidae, a large monophyletic group consisting of four orders. Magnoliidae (Canellales, Larales, Magnoliales, Piperales) with about 10,000 species are remarkably diverse in floral structures in contrast to monocots and eudicots, which appear to have relatively well-conserved floral ground plans. To understand the evolutionary, developmental, and ecological processes responsible for the floral diversity of Magnoliidae, first a robust, dated phylogeny for the group will be reconstructed; secondly, a comprehensive database of floral traits of Magnoliidae combining literature data as well as new observations will be created and tested for correlations among floral characters as well as between floral morphology, pollinating vectors, and diversification rates. Subsequently, the floral transcriptomes of selected species will be characterized. Unraveling the history and mechanisms of floral diversification in Magnoliidae will not only shed light on an enigmatic piece of the puzzle of angiosperm evolution, but will also provide invaluable insights into early floral evolution and the origin of monocots and eudicots.


Evolution in Malvales

The delimitation of families in the core Malvales has traditionally been problematic. Molecular phylogenetic studies have confirmed the monophyly of the core Malvales, but do not support the traditional family-level classification. We study the flower development and structure of various clades in the family with the aim to find synapomorphies for new clades and to understand the often complicated structure of the androecium.


eflower

A large collaborative work, project leader Hervé Sauquet, University of Paris-Sud XI, Orsay, France
http://eflower.myspecies.info


Diversity and evolution of the floral morphospace

A striking feature of organismal morphological variation is that not all the theoretically possible architectures have been explored during the evolution of species. Existing morphologies are restricted to a limited set because of developmental, functional, and phylogenetic constraints. In this project, we propose to compare the occupied portion of the morphological space (or morphospace) through geological time and among distinct clades. This project focuses on physical and biological rules, convergence and contingency at play during the evolution of natural shapes. As a model group, we have chosen the angiosperms. The immense morphological disparity found among angiosperms (especially in their floral parts), the availability of fossils, the accumulation of dated phylogenies, and the recent technical improvement for visualizing and quantifying morphological traits all provide a strong basis for our project.


Phylogenetics and systematics of Rubiaceae-Rubieae

Intensive DNA-analytical studies of this world-wide and ecologically highly diverse clade (about 1400 species) have resulted in the phylogram presented: Established genera are underlined, sections of Asperula are shown in red, those of Galium in blue. It is obvious that this taxonomic scheme is partly in conflict with phylogenetic relationships (indicated by Roman numbers, capital letters and branch outlines). Uniting clades IV, V and VI under a much enlarged genus Galium might solve this problem. Efforts are under way to reach better solution.


Evolution in Capsicum (Solanaceae)

Clarifying the evolution of this economically most important Solanaceous genus is a close cooperation with a research group in Cordoba, Argentina. We participate in efforts to clarify this South American genus (about 40 species), including the numerous pepper cultivars. Multidisciplinary approaches (including analyses of various DNA markers) should help towards clarifying the dysploid changes from x = 12 to x = 13 and the still insufficient taxonomy of the genus.


Phylogenetic relationships of the tropical tree family Dipterocarpaceae

Dipterocarpaceae comprise more than 500 species and usually have been considered to include three subfamilies: Monotoideae (three genera) distributed in Africa, Madagascar and the Colombian Amazon, monospecific Pakaraimaeoideae occurring in the Guianan Highlands of South America, and the largest Dipterocarpoideae (nine to 19 genera depending on the author) which can be found in the Seychelles, Sri Lanka, India and Southeast Asia to New Guinea. Here, we present the first molecular phylogenetic study including all three subfamilies of Dipterocarpaceae and closely related families of the order Malvales. Research comprises phylogenetic analysis using plastid DNA sequences including all three subfamilies of Dipterocarpaceae and closely related families of the order Malvales. Further, restriction-site associated sequencing (RAD sequencing) will be used to investigate the tribe Shoreae, especially the genus Shorea which is not monophyletic.
Funded by the Austrian Science Fund (FWF).

For information, visit the project homepage: http://www.botanik.univie.ac.at/systematik/projects/dipterocarp/


DNA Barcoding and community structure assessment of a tropical forest: a 25 ha mixed dipterocarp forest at Kuala Belalong Brunei Darussalam as a model

DNA barcoding is a fast and reliable tool to assess and monitor biodiversity and has a role to play in investigating processes that are responsible for species interactions and thus the community structure of forests. Here, we use DNA barcoding to assess phylogenetic community structure of a 25 ha forest dynamics plot in a mixed dipterocarp forest in Brunei Darussalam which is part of the Center for Tropical Forest Science - Forest Global Earth Observatory (CTFS-ForestGEO) network of plots.
Funded by the Austrian Science Fund (FWF).

For information, visit the project homepage: http://www.botanik.univie.ac.at/systematik/projects/dipterocarp/


Evolution and Biodiversity of New Caledonian Diospyros

Diospyros forms a large genus of woody flowering plants of the family Ebenaceae. Of  31 Diospyros species found in New Caledonia, 30 are endemic. Previous phylogenetic studies of the genus Diospyros based on sequences of plastid markers, showed the New Caledonian species to form three groups. Two of these groups contain only few species (2 to 5), and the majority of species (24) forms the third group.  In our first study based on sequence data we observed the species of group 3 are closely related. Diospyros vieillardii is clearly shown to be sister to the rest of this group and individuals of only four species formed unique groups. Species delimitations inferred from next generation sequencing technique RAD (Restriction site associated DNA) are comparable to those obtained from AFLP data. Phylogenetic trees based on thousands of RAD-derived SNPs (single nucleotide polymorphism) are much better resolved than those based on Sanger sequencing of nuclear and plastid markers.  The observed phylogenetic relationships do not follow an ecological structure, pointing to a role of environmental heterogeneity of New Caledonia in shaping speciation events in this group.  Species from group 3 revealed nearly 3-fold larger genome sizes compared to Diospyros species from other groups. Chromosome counts showed no indication of polyploidy in this group. Repeated elements as well as  plastid sequences and reads corresponding to the nuclear ribosomal DNA (nrDNA), were obtained from the low-coverage whole genome sequencing. These reads could be assembled to whole plastid genomes and nearly complete nrDNA regions. The obtained plastomes were compared to the plastid sequence of Camellia sinensis instructural organization and gene content. Dating analyses based on DNA sequence and RAD data showed that the crown group 3 is around seven million years old.
P22159-B16 project funded by the Austrian Science Fund (FWF).

For more information, visit the project homepage: http://www.botanik.univie.ac.at/systematik/projects/diospyros/index.html