Taxonomic revision of the Genus Leontopodium

The project aims at a total taxonomic revision of the genus Leontopodium investigating morphological properties, molecular phylogeny, genetic fingerprinting and secondary metabolite profiles of individual species. Up to now, Leontopodium including the European Edelweiss has received little taxonomic attention. In fact, it is barely known that this genus comprises about forty different Edelweiss species. Its center of diversity is central Asia, underlying the radiation history of Edelweiss. This makes this genus a prominent example for evolution of the Eurasian flora. The only complete taxonomic revision of Leontopodium dates back to 1927 when N. Handel-Mazzetti recognized forty-one species and some putative hybrids in the genus. However, species delimitation in Leontopodium is notoriously difficult. In the course of this project, the morphological-taxonomic classification of the genus Leontopodium will be revised by investigating a large number of collected taxa and representative herbarium specimens to produce a refined classification as well as a morphological and biometric description of all species. Phylogenetic analyses will be performed using ITS, plastid regions such as trnH-psbA and matK, and a low copy nuclear gene sequence. Data matrices of both plastid and nuclear markers will be analyzed individually and tested for combinability. AFLP will be used to answer questions on genetic divergence, hybridization, polyploidization and phylogeography in L. alpinum and L. nivale in the European Alps. Metabolic profiling of Leontopodium specimens will be carried out on the basis of 1H NMR spectroscopy. This methodology allows investigation of a large number of samples with rather complex secondary metabolite patterns, which do not yield to common analytical/chemotaxonomic techniques. The secondary metabolite pattern recognition is directly based on the chemical structure of the plant constituents, requiring only one proton in the molecular formula. This universal method is completely independent from common detection requirements such as UV absorption, ionization (rate), refraction index and combines the advantages of the required small sample amounts (100 mg) and an easy sample preparation yielding at the same time maximum information output. Therefore, the dried plant material is ground, extracted directly with NMR-solvent, and measured in a conventional NMR tube. The obtained spectra are evaluated by principal component analysis (PCA), resulting in a "cluster plot", yielding simultaneously additional structure information (chemical shift, multiplicity of the NMR signals) of the "discriminating" signals. Results obtained in the course of this project should lead to a concise worldwide (i.e. Eurasia-wide) revision of the genus Leontopodium (and Sinoleontopodium) with a view of a geographically and bio-systematically representative coverage. The output will be a modern monograph of a remarkable and typical alpine genus, including a methodically exhaustive and integrative approach.

The European Edelweiss is one of the most famous and symbolic plants of the Alps. Relatively unknown is the fact, that the Edelweiss-family comprises ca. 35 different species with a major distribution area in Asia (e.g. parts of Mongolia or the Tibetan plateau). The performed studies aimed on the illumination of the relationship of the European and Asiatic Edelweiss species. This plan was followed by two different approaches: by the study of the genetic diversity as well as the comparison of the secondary plant metabolites. The genetic investigations were carried out by the analysis of 216 individuals from 38 populations out of 16 different Edelweiss species. The major part of the investigated samples was collected in the province of Yunnan/China but also in Mongolia, Bulgaria and Switzerland. A comparison of the genetic fingerprints obtained by AFLP enabled the classification of the analyzed samples into 10 different groups, including two monophyletic groups namely the European species and the Mongolian representatives of the genus. The origin of all species is most likely the Chinese Himalayan region. Analysis of the secondary plant metabolites of the root material of the collected Edelweiss species by 1 H-NMR- metabolic profiling and HPLC-ESI-MS followed by multivariate statistic revealed in contrast to the genetic investigations a separation in two ( 1 H-NMR-metabolic profiling) and three (HPLC-ESI-MS) major groups. The observed discrimination in the performed NMR-experiments was a result of varying concentrations of fatty acids and sucrose as well as kaurenoic acid and its derivatives. In contrast the HPLC-ESI-MS experiments discriminated between species containing different bisabolane derivatives, and again kaurenoic acid derivatives. The use of both applied techniques for the investigation of the composition of secondary plant metabolites enabled a verification of the genetic data and offers new perspectives in the field of chemo-taxonomy.