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Journal article

Allopolyploid origin of highly invasive Centaurea stoebe s.l. (Asteraceae)

  • Mráz, Patrik Department of Biology, Unit of Ecology & Evolution, University of Fribourg, Switzerland
  • Garcia-Jacas, Núria Botanic Institute of Barcelona (IBB-CSIC-ICUB), Barcelona, Spain
  • Gex-Fabry, Emilie Department of Biology, Unit of Ecology & Evolution, University of Fribourg, Switzerland
  • Susanna, Alfonso Botanic Institute of Barcelona (IBB-CSIC-ICUB), Barcelona, Spain
  • Barres, Laia Botanic Institute of Barcelona (IBB-CSIC-ICUB), Barcelona, Spain
  • Müller-Schärer, Heinz Department of Biology, Unit of Ecology & Evolution, University of Fribourg, Switzerland
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    20.11.2011
Published in:
  • Molecular Phylogenetics and Evolution. - 2012, vol. 62, no. 2, p. 612–623
Allopolyploidy
Centaurea maculosa
cpDNA
Flow cytometry
Invasion
ITS
Hybridization
Life history traits
nrDNA
Polyploidy
English Spotted knapweed (Centaurea stoebe) occurs from Western Asia to Western Europe both as diploid and tetraploid cytotypes, predominantly in single-cytotype populations with higher frequency of diploid populations. Interestingly, only tetraploids have been recorded so far from its introduced range in North America where they became highly invasive. We performed phylogenetic and network analyses of more than 40 accessions of the C. stoebe and C. paniculata groups and other related taxa using cloned internal transcribed spacer (ITS) and sequences of the chloroplast trnT–trnL and atpBrbcL regions to (i) assess the evolutionary origin of tetraploid C. stoebe s.l., and (ii) uncover the phylogeny of the C. stoebe group. Both issues have not been studied so far and thus remained controversial. Cloned ITS sequences showed the presence of two slightly divergent ribotypes occurring in tetraploid cytotype, while only one major ribotype was present in diploid C. stoebe s.str. This pattern suggests an allopolyploid origin of tetraploids with contribution of the diploid C. stoebe s.str. genome. Although we were not able to detect the second parental taxon, we hypothesize that hybridization might have triggered important changes in morphology and life history traits, which in turn may explain the colonization success of the tetraploid taxon. Bayesian relaxed clock estimations indicate a relatively recent – Pleistocene origin of the tetraploid C. stoebe s.l. Furthermore, our analyses showed a deep split between the C. paniculata and C. stoebe groups, and a young diversification of the taxa within the C. stoebe group. In contrast to nrDNA analyses, the observed pattern based on two cpDNA regions was inconclusive with respect to the origin and phylogeny of the studied taxa, most likely due to shared ancient polymorphism and frequent homoplasies.
Faculty
Faculté des sciences et de médecine
Department
Département de Biologie
Language
  • English
Classification
Ecology and biodeversity
License
License undefined
Identifiers
Persistent URL
https://folia.unifr.ch/unifr/documents/302328
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