In recent years a few phylogenetic and phylogeographic studies of diploid plants from the Balkans have revealed complex patterns in the geographic distribution of genetic diversity and challenged traditional taxonomic concepts. In our study, we will address the significance of polyploid evolution for the high species diversity of the Balkans and explore biogeographic connections with adjacent areas (e.g., Alps). Molecular methods will be employed to unravel the phylogenetic history, to search for cryptic taxa, and to disentangle phylogeographic relationships within the selected groups. Using a molecular phylogenetic framework, we will explore the relationships among diploid taxa and their role in formation of polyploid descendents. Polyploidisation is considered an important mechanism allowing sympatric speciation, a mode whose importance for speciation is still controversial. Both allopolyploids (involving a hybridisation step) and autopolyploids (originating within species) have been shown to have multiple independent origins and to be successfully maintained, emphasising their evolutionary significance. Moreover, as evident from recent studies, ploidy level differences are not restricted to the species level, but also occur within species.
Previous studies have shown that polyploidisation played an important role in the evolution and diversification of the genera
Cerastium (Caryophyllaceae),
Knautia
(Dipsacaceae), and
Sesleria (Poaceae), which have their centres of diversity on the Balkan Peninsula. Polyploidisation was likely involved in formation of several stenoendemic taxa from these groups, distributed in narrow geographic areas. Nevertheless, detailed studies using contemporary molecular method are lacking for these groups, which are often cultivated as ornamentals (
Cerastium
and
Knautia) or represent the most important forage source in the mountainous areas of the Balkans (
Sesleria). We will thus use these groups as model organisms, and apply well-established molecular and cytogenetic methods to evaluate the significance of polyploidisation for the high plant diversity of the Balkans. Specifically, using freshly collected plant material from different regions of south-eastern Europe we will (1) estimate the ploidy-level of all indigenous species belonging to our target genera by means of flow cytometry, (2) uncover phylogenetic relationships among diploid taxa of each genus, aiming at a complete coverage, including at least two populations from each species. In some cases collecting activities will be extended to areas outside the Balkans (e.g., Alps). Sequencing of plastid, nuclear ribosomal (ITS) and low-copy nuclear DNA regions will be performed at this step. (3) The phylogenetic position and (allo- or autopolyploid) origin of polyploid taxa will be studied using the established phylogenetic framework of diploid taxa. This step will additionally to the above-mentioned techniques require molecular cloning of nuclear low-copy DNA regions. (4) Highly resolving fingerprinting data (AFLPs) will be generated for groups of closely related species where no sufficient resolution can be obtained with sequence data, as well as for the intraspecific, conservation-genetic study of the rare Natura 2000 species
Cerastium dinaricum. (5) Using molecular dating, we will try to infer the timing of splitting and polyploidisation and link these events with the geological history of the Balkans and thus test for temporal coincidence within and among different plant groups. We will use our results to evaluate the conservation status of endemic, rare and endangered species included in our study, based on internationally accepted IUCN criteria and in accordance with EU principles, taking into account also the intraspecific diversity in the selection of networks of protected areas. Specifically, we will use the Balkan endemic
Cerastium dinaricum
, a qualifying species for Natura 2000 sites (Annex II of the Habitats Directive), as a model to define potential Sites of Community Interest, which cover the entire genetic diversity of this indigenous species.
