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

Comparison of genetic diversity in two alien plant species

Bunias orientalis and Erigeron annuus are two alien herbal plant species invading native ecosystems in Lithuania. Both species have similar introduction and invasion history but differ in their life history traits and strategies of reproduction. We used random amplified polymorphic DNA (RAPD) data to compare the genetic diversity in invasive populations of these species. 42 RAPD bands were identified in B. orientalis and 70 RAPD bands in E. annuus. All six populations of B. orientalis were polymorphic, while only four of eight study populations of E. annuus were polymorphic. The highest differences between species were established at the level of RAPD phenotypes. 67 RAPD phenotypes were found among 90 plants of B. orientalis but only 10 RAPD phenotypes were identified among 89 plants of E. annuus. This study shows that the level of genetic diversity in populations of different invasive species at the same geographic area may vary considerably. Keywords: Bunias orientalis, Erigeron annuus, genetic diversity, RAPD phenotypeVergleich der genetischen Vielfalt von zwei nicht-einheimischen PflanzenartenBunias orientalis und Erigeron annuus sind zwei nicht-einheimische Pflanzenarten, die in litauische natürliche Ökosysteme eindringen. Eindringungs- und Invasionswege beider Arten sind ähnlich. Unterschiede liegen in den Entwicklungs- und Reproduktionsbesonderheiten. In dieser Arbeit haben wir anhand der Ergebnisse von random amplified polymorphic DNA (RAPD) die genetische Vielfalt von verschiedenen Populationen dieser nicht-einheimischen Arten verglichen. 42 RAPD Banden wurden bei B. orientalis und 70 bei E. annuus festgestellt. Alle sechs B. orientalis-Populationen waren polymorph; bei E. annuus waren es nur vier von acht Populationen. Die größte Differenz zwischen den Arten zeigten die RAPD-Phänotypen. Bei 90 B. orientalis-Pflanzen wurden 67 RAPD-Phänotypen identifiziert aber nur 10 RAPD-Phänotypen bei 89 E. annuus-Pflanzen. Die Ergebnisse zeigen, dass die genetische Vielfalt der nicht-einheimischen Pflanzenarten auf demselben geographischen Territorium wesentliche Unterschiede aufweisen kann. Stichwörter: Bunias orientalis, Erigeron annuus, genetische Vielfalt, RAPD-Phänotype

Application of barley tweaky spike mutants for the study of effects of plant immunity‐related substances

Barley developmental mutants tweaky spike (tw) with disturbed auxin pathways possess a unique feature of an increased level of mouldy germinating grains (MGG), which serves as a convenient model to investigate the effects of plant immunity‐related substances. The effects of the auxin 2,4‐dichlorophenoxyacetic acid (2,4‐D), auxin inhibitors, salicylic acid (SA), and trans‐cinnamic acid (TCA) were studied using the tw‐WT system in surface‐sterilized and unsterilized germinating grains under high rates of natural infection. Significant differences among the allelic tw mutants were revealed at the natural MGG level and in response to 2,4‐D, SA, and TCA. The most effective means against MGG were sterilization and TCA. 2,4‐D inhibited root growth in tw and tw2 mutants, occurring only in unsterilized and not sterilized germinating grains, while the opposite was observed for TCA and SA. The tw mutations influenced variations in the seed‐borne fungal spectra, decreasing the frequency of Bipolaris sorokiniana and increasing Fusarium spp. Hypochlorite‐based surface sterilization methods should be used with caution in studies where the action of exogenous 2,4‐D will be analysed in germinating grains. Auxin pathway disturbances specific for pleiotropic tw mutants are generally restricted to organogenesis but not to germination events

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