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Polyploidisation and geographic differentiation drive diversification in a European High Mountain Plant Group (Doronicum clusii Aggregate, Asteraceae).

Pachschwöll C, Escobar García P, Winkler M, Schneeweiss GM, Schönswetter P - PLoS ONE (2015)

Bottom Line: Taxonomic conclusions were informed, among others, by a Gaussian clustering method for species delimitation using dominant multilocus data.Doronicum glaciale subsp. calcareum was genetically and morphologically weakly separated from D. glaciale subsp. glaciale but exhibited significantly higher genetic diversity and rarity.This suggests that the more widespread D. glaciale subsp. glaciale originated from D. glaciale subsp. calcareum, which is restricted to a prominent Pleistocene refugium previously identified in other alpine plant species.

View Article: PubMed Central - PubMed

Affiliation: Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030 Vienna, Austria.

ABSTRACT
Range shifts (especially during the Pleistocene), polyploidisation and hybridization are major factors affecting high-mountain biodiversity. A good system to study their role in the European high mountains is the Doronicum clusii aggregate (Asteraceae), whose four taxa (D. clusii s.s., D. stiriacum, D. glaciale subsp. glaciale and D. glaciale subsp. calcareum) are differentiated geographically, ecologically (basiphilous versus silicicolous) and/or via their ploidy levels (diploid versus tetraploid). Here, we use DNA sequences (three plastid and one nuclear spacer) and AFLP fingerprinting data generated for 58 populations to infer phylogenetic relationships, origin of polyploids-whose ploidy level was confirmed by chromosomally calibrated DNA ploidy level estimates-and phylogeographic history. Taxonomic conclusions were informed, among others, by a Gaussian clustering method for species delimitation using dominant multilocus data. Based on molecular data we identified three lineages: (i) silicicolous diploid D. clusii s.s. in the Alps, (ii) silicicolous tetraploid D. stiriacum in the eastern Alps (outside the range of D. clusii s.s.) and the Carpathians and (iii) the basiphilous diploids D. glaciale subsp. glaciale (eastern Alps) and D. glaciale subsp. calcareum (northeastern Alps); each taxon was identified as distinct by the Gaussian clustering, but the separation of D. glaciale subsp. calcareum and D. glaciale subsp. glaciale was not stable, supporting their taxonomic treatment as subspecies. Carpathian and Alpine populations of D. stiriacum were genetically differentiated suggesting phases of vicariance, probably during the Pleistocene. The origin (autopolyploid versus allopolyploid) of D. stiriacum remained unclear. Doronicum glaciale subsp. calcareum was genetically and morphologically weakly separated from D. glaciale subsp. glaciale but exhibited significantly higher genetic diversity and rarity. This suggests that the more widespread D. glaciale subsp. glaciale originated from D. glaciale subsp. calcareum, which is restricted to a prominent Pleistocene refugium previously identified in other alpine plant species.

No MeSH data available.


Related in: MedlinePlus

Investigated populations of the Doronicum clusii aggregate in the Alps and Carpathians.Population numbers are as in Table 2; taxonomic entities are colour-coded: D. glaciale subsp. calcareum (yellow), D. glaciale subsp. glaciale (red) and their morphological intermediates (orange); D. stiriacum (green); D. clusii s.s. (blue); hybrids between D. clusii s.s. and D. glaciale subsp. glaciale (D. × bauhini; lavender). The insert shows Carpathian populations of D. stiriacum (turquoise); for graphical reasons the insert is in the upper left despite the Carpathians being east of the Alps. The coloured outlines are distribution ranges summarized according to various literature sources, herbarium specimens and personal observations. Scale bars: 50 km.
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pone.0118197.g001: Investigated populations of the Doronicum clusii aggregate in the Alps and Carpathians.Population numbers are as in Table 2; taxonomic entities are colour-coded: D. glaciale subsp. calcareum (yellow), D. glaciale subsp. glaciale (red) and their morphological intermediates (orange); D. stiriacum (green); D. clusii s.s. (blue); hybrids between D. clusii s.s. and D. glaciale subsp. glaciale (D. × bauhini; lavender). The insert shows Carpathian populations of D. stiriacum (turquoise); for graphical reasons the insert is in the upper left despite the Carpathians being east of the Alps. The coloured outlines are distribution ranges summarized according to various literature sources, herbarium specimens and personal observations. Scale bars: 50 km.

Mentions: The monophyletic D. clusii aggregate comprises four geographically, ecologically and/or karyologically differentiated subalpine to subnival forbs restricted to the European mountain systems of the Alps and the Carpathians [49,57,58,59]. They possess yellow, showy flower heads that are visited and pollinated by various Diptera, Hymenoptera and Lepidoptera [60,61]. These four taxa are grouped in two pairs [58,59] (summarized in Table 1; for more detailed descriptions see S1 Appendix): (i) D. glaciale (Wulf.) Nyman subsp. calcareum (Vierh.) Hegi from the northeastern-most Alps and the parapatric D. glaciale (Wulf.) Nyman subsp. glaciale from the eastern Alps (Fig. 1, S1 Appendix) are diploid (2n = 60) and basiphilous growing on calcareous or, in case of D. glaciale subsp. glaciale, also on base-rich siliceous substrate; (ii) D. clusii (All.) Tausch s.s. (i.e., excluding D. stiriacum (Vill.) Dalla Torre) from the Alps (except the easternmost parts) and the allopatric D. stiriacum from the easternmost Central Alps and the Carpathians (Fig. 1, S1 Appendix) are acidophilic, but differ in being diploid (2n = 60) and tetraploid (2n = 120), respectively. Whereas a geographically restricted contact zone with morphologically intermediate individuals links D. glaciale subsp. calcareum and D. glaciale subsp. glaciale (Fig. 1; S1 Appendix), putative hybrids between D. clusii s.s. and D. glaciale subsp. glaciale occur throughout their overlapping distribution ranges in the eastern Central Alps (Fig. 1; S1 Appendix). The Alpine distribution ranges of both D. glaciale subsp. calcareum and D. stiriacum overlap with Pleistocene refugia [4,5,38] suggesting that their differentiation might be connected to this period.


Polyploidisation and geographic differentiation drive diversification in a European High Mountain Plant Group (Doronicum clusii Aggregate, Asteraceae).

Pachschwöll C, Escobar García P, Winkler M, Schneeweiss GM, Schönswetter P - PLoS ONE (2015)

Investigated populations of the Doronicum clusii aggregate in the Alps and Carpathians.Population numbers are as in Table 2; taxonomic entities are colour-coded: D. glaciale subsp. calcareum (yellow), D. glaciale subsp. glaciale (red) and their morphological intermediates (orange); D. stiriacum (green); D. clusii s.s. (blue); hybrids between D. clusii s.s. and D. glaciale subsp. glaciale (D. × bauhini; lavender). The insert shows Carpathian populations of D. stiriacum (turquoise); for graphical reasons the insert is in the upper left despite the Carpathians being east of the Alps. The coloured outlines are distribution ranges summarized according to various literature sources, herbarium specimens and personal observations. Scale bars: 50 km.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4352020&req=5

pone.0118197.g001: Investigated populations of the Doronicum clusii aggregate in the Alps and Carpathians.Population numbers are as in Table 2; taxonomic entities are colour-coded: D. glaciale subsp. calcareum (yellow), D. glaciale subsp. glaciale (red) and their morphological intermediates (orange); D. stiriacum (green); D. clusii s.s. (blue); hybrids between D. clusii s.s. and D. glaciale subsp. glaciale (D. × bauhini; lavender). The insert shows Carpathian populations of D. stiriacum (turquoise); for graphical reasons the insert is in the upper left despite the Carpathians being east of the Alps. The coloured outlines are distribution ranges summarized according to various literature sources, herbarium specimens and personal observations. Scale bars: 50 km.
Mentions: The monophyletic D. clusii aggregate comprises four geographically, ecologically and/or karyologically differentiated subalpine to subnival forbs restricted to the European mountain systems of the Alps and the Carpathians [49,57,58,59]. They possess yellow, showy flower heads that are visited and pollinated by various Diptera, Hymenoptera and Lepidoptera [60,61]. These four taxa are grouped in two pairs [58,59] (summarized in Table 1; for more detailed descriptions see S1 Appendix): (i) D. glaciale (Wulf.) Nyman subsp. calcareum (Vierh.) Hegi from the northeastern-most Alps and the parapatric D. glaciale (Wulf.) Nyman subsp. glaciale from the eastern Alps (Fig. 1, S1 Appendix) are diploid (2n = 60) and basiphilous growing on calcareous or, in case of D. glaciale subsp. glaciale, also on base-rich siliceous substrate; (ii) D. clusii (All.) Tausch s.s. (i.e., excluding D. stiriacum (Vill.) Dalla Torre) from the Alps (except the easternmost parts) and the allopatric D. stiriacum from the easternmost Central Alps and the Carpathians (Fig. 1, S1 Appendix) are acidophilic, but differ in being diploid (2n = 60) and tetraploid (2n = 120), respectively. Whereas a geographically restricted contact zone with morphologically intermediate individuals links D. glaciale subsp. calcareum and D. glaciale subsp. glaciale (Fig. 1; S1 Appendix), putative hybrids between D. clusii s.s. and D. glaciale subsp. glaciale occur throughout their overlapping distribution ranges in the eastern Central Alps (Fig. 1; S1 Appendix). The Alpine distribution ranges of both D. glaciale subsp. calcareum and D. stiriacum overlap with Pleistocene refugia [4,5,38] suggesting that their differentiation might be connected to this period.

Bottom Line: Taxonomic conclusions were informed, among others, by a Gaussian clustering method for species delimitation using dominant multilocus data.Doronicum glaciale subsp. calcareum was genetically and morphologically weakly separated from D. glaciale subsp. glaciale but exhibited significantly higher genetic diversity and rarity.This suggests that the more widespread D. glaciale subsp. glaciale originated from D. glaciale subsp. calcareum, which is restricted to a prominent Pleistocene refugium previously identified in other alpine plant species.

View Article: PubMed Central - PubMed

Affiliation: Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030 Vienna, Austria.

ABSTRACT
Range shifts (especially during the Pleistocene), polyploidisation and hybridization are major factors affecting high-mountain biodiversity. A good system to study their role in the European high mountains is the Doronicum clusii aggregate (Asteraceae), whose four taxa (D. clusii s.s., D. stiriacum, D. glaciale subsp. glaciale and D. glaciale subsp. calcareum) are differentiated geographically, ecologically (basiphilous versus silicicolous) and/or via their ploidy levels (diploid versus tetraploid). Here, we use DNA sequences (three plastid and one nuclear spacer) and AFLP fingerprinting data generated for 58 populations to infer phylogenetic relationships, origin of polyploids-whose ploidy level was confirmed by chromosomally calibrated DNA ploidy level estimates-and phylogeographic history. Taxonomic conclusions were informed, among others, by a Gaussian clustering method for species delimitation using dominant multilocus data. Based on molecular data we identified three lineages: (i) silicicolous diploid D. clusii s.s. in the Alps, (ii) silicicolous tetraploid D. stiriacum in the eastern Alps (outside the range of D. clusii s.s.) and the Carpathians and (iii) the basiphilous diploids D. glaciale subsp. glaciale (eastern Alps) and D. glaciale subsp. calcareum (northeastern Alps); each taxon was identified as distinct by the Gaussian clustering, but the separation of D. glaciale subsp. calcareum and D. glaciale subsp. glaciale was not stable, supporting their taxonomic treatment as subspecies. Carpathian and Alpine populations of D. stiriacum were genetically differentiated suggesting phases of vicariance, probably during the Pleistocene. The origin (autopolyploid versus allopolyploid) of D. stiriacum remained unclear. Doronicum glaciale subsp. calcareum was genetically and morphologically weakly separated from D. glaciale subsp. glaciale but exhibited significantly higher genetic diversity and rarity. This suggests that the more widespread D. glaciale subsp. glaciale originated from D. glaciale subsp. calcareum, which is restricted to a prominent Pleistocene refugium previously identified in other alpine plant species.

No MeSH data available.


Related in: MedlinePlus