Relationships and generic delimitation of Eurasian genera of the subtribe Asterinae (Astereae, Asteraceae) using molecular phylogeny of ITS

摘要

The subtribe Asterinae (Astereae, Asteraceae) includes highly variable, often polyploid species. Recent findings based on molecular methods led to revision of its volume. However, most of these studies lacked species from Eurasia, where a lot of previous taxonomic treatments of the subtribe exist. In this study we used molecular phylogenetics methods with internal transcribed spacer (ITS) as a marker to resolve evolutionary relations between representatives of the subtribe Asterinae from Siberia, Kazakhstan, and the European part of Russia. Our reconstruction revealed that a clade including all Asterinae species is paraphyletic. Inside this clade, there are species with unresolved basal positions, for example Erigeron flaccidus and its relatives. Moreover, several well-supported groups exist: group of the genera Galatella, Crinitaria, Linosyris, and Tripolium; group of species of North American origin; and three related groups of Eurasian species: typical Eurasian asters, Heteropappus group (genera Heteropappus, Kalimeris), and Asterothamnus group (genera Asterothamnus, Rhinactinidia). The results obtained confirm previous findings with notable exceptions and add important phylogenetic data for 15 previously unstudied species, 11 of which are narrow Asian endemics. Conclusions of this study clarify relations between species and genera within this subtribe. Further molecular phylogenetics analyses of the remaining Eurasian species are needed for taxonomic revision and segregation of Asterinae into several subtribes.