Genotypic diversity and clonal structure of Erigeron annuus (Asteraceae) in Lithuania

This study was conducted to assess the clonal structure and genetic diversity of alien herbaceous plant species Erigeron annuus. The global warming and changes in agriculture practice in the past few decades were favourable for the expansion of this species in Lithuania. We used RAPD and ISSR assays to assess genetic variation within and among 29 populations of E. annuus. A total of 278 molecular markers were revealed. Our study detected reduced level of genetic diversity of invasive populations of E. annuus. Significant differences in DNA polymorphism among populations of E. annuus were also found. Some populations of this species are composed of genetically identical plants, while others were polymorphic. Clonal diversity of study populations ranged from 0.083 to 0.4 for both DNA marker systems. The Simpsons diversity index values ranged from 0.0 to 0.636. The average number of genotypes per population established using both assays was about 1.7. Out of 328 E. annuus individuals only 16 showed unique RAPD and 14 unique ISSR banding patterns. The remaining plants were clones of different size. The most common genotype of E. annuus identified in our study was represented by predominate in nine populations.Keywords: Clonal structure, DNA markers, Erigeron annuus, invasive plants, ISSR, RAPDGenetische Vielfalt und Klonstruktur von Erigeron annuus (Asteraceae) in LitauenZusammenfassungDie Untersuchungen verfolgen das Ziel, die genetische Struktur der nicht-einheimischen Pflanzenart Erigeron annuus auszuwerten. Globale Erwärmung sowie Veränderungen in der landwirtschaftlichen Praxis der letzten Jahrzehnte waren bedeutsam für die Verbreitung dieser Art in Litauen. Für die Feststellung der genetischen Verteilungsvielfalt in den 29 E. annuus Populationen haben wir uns der RAPD und ISSR -Methoden bedient. Insgesamt wurden 117 RAPD - und 161 ISSR - Loci festgestellt. Die Untersuchungen haben die verringerte genetische Vielfalt der E. annuus Populationen aufgezeigt. Außerdem wurden bedeutende DNR polymorphe Unterschiede zwischen E. annuus Populationen angetroffen. Einige Populationen dieser Art bestanden aus genetisch identischen Pflanzen, während die anderen polymorphem waren. Die Klonvielfalt der untersuchten Populationen schwankte zwischen 0.083 und 0.4 bei der Verwendung von beiden DNR-Signifikanten. Die durchschnittliche Genotypen Zahl in der Population betrug etwa 1.7 bei der Verwendung von beiden Signifikanten. Nach der Untersuchung der 328 E. annuus Individuen wurden 16 unikale RAPD - und 14 unikale ISSR - Phänotypen festgestellt. Die übriggebliebenen Pflanzen waren Klonen von unterschiedlicher Größe. Der am meisten verbreitete E. annuus Genotyp wurde in neun Populationen ermittelt.Stichwörter: DNS- Marker, Erigeron annuus, ISSR, Klonstruktur, invasive Pflanzen, RAP

Erigeron annuus genetinės įvairovės gradientas rūšies Europos invazinio arealo dalyje

Erigeron annuus (L.) Pers. (Asteraceae) is native species to eastern North America, but has been introduced to Europe and many other temperate regions of the world. In order to assess the impact of spreading history and settlement time on the genetic diversity of invasive populations of E. annuus, individual plants were sampled from 16 populations located in Switzerland, Poland, Lithuania and Latvia along the south-northern expansion direction of this species in Europe. One population was collected in native range (New Brunswick, Canada). The analysis of ISSR polymorphism in 253 plants revealed 161 polymorphic bands. The highest genotype variation and genetic diversity parameters were revealed in the populations from Switzerland and Poland, the least – in Latvian populations. All 37 plants from Latvia were clones of the same genotype. The comparison of genetic diversity parameters of populations from different countries showed the decrease of genetic diversity on the south-north direction

Different Habitats Show Similar Genetic Structure of <i>Bunias orientalis</i> L. (Brassicaceae)in Lithuania

We studied genetic diversity within and among populations of warty cabbage (Bunias orientalis L.), which is an alien species in Lithuania and other Baltic countries. In Lithuania, this weed colonises two main types of habitats: railway/roadsides and meadows on riversides. The aim of this study was to assess the genetic structure of invasive populations of B. orientalis in Lithuania and consider the impact of diverse habitats on the partitioning of genetic diversity using inter-simple sequence repeat (ISSR) markers. An analysis of molecular variance (AMOVA) carried out on the basis of ISSR showed that there is high genetic differentiation (46%) among populations of B. orientalis, which is probably caused by the founder effect and limited gene flow. However, we observed no impact of habitat on the genetic difference among populations. Similar levels of ISSR polymorphic loci were observed in riverside (P = 31.67%) and railway/roadsides (P = 30.51%) populations. UPGMA cluster analysis and principal coordinate analysis (PCoA) also did not show grouping of studied populations according to habitat type. High genetic differentiation among populations, as indicated by ISSR markers, confirm multiple independent introductions of this species in Lithuania