J Plant Ecol ›› 2018, Vol. 11 ›› Issue (2): 317-327 .DOI: 10.1093/jpe/rtx005

• Research Articles • Previous Articles     Next Articles

Does higher ploidy level increase the risk of invasion? A case study with two geo-cytotypes of Solidago gigantea Aiton (Asteraceae)

David U. Nagy1,*, Szilvia Stranczinger2, Aliz Godi2, Anett Weisz2, Christoph Rosche3, Jan Suda4, Mark Mariano5 and Robert W. Pal1,5   

  1. 1 Department of Ecology, Institute of Biology, Faculty of Sciences, University of Pécs, H-7624 Pécs, Ifjúság u. 6, Hungary; 2 Department of Botany, Institute of Biology, Faculty of Sciences, University of Pécs, H-7624 Pécs, Ifjúság u. 6, Hungary; 3 Working Group: Plant Ecology, Institute of Biology / Geobotany and Botanical Garden, Martin Luther University Halle-Wittenberg, Am Kirchtor 1, D-06108 Halle, Germany; 4 Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, CZ-128 01 Prague, Czech Republic and Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43 Pr?honice, Czech Republic; 5 Department of Biological Sciences, Montana Tech, Montana Tech of the University of Montana, 1300 W Park StMT 59701 Butte, USA
  • Received:2016-04-22 Accepted:2017-01-24 Published:2018-02-06
  • Contact: Nagy, Dávid

Does higher ploidy level increase the risk of invasion? A case study with two geo-cytotypes of Solidago gigantea Aiton (Asteraceae)

Abstract: Aims Understanding the role of genetics in biological invasions has become an important aspect for modern plant ecology. Many studies suggest that increased ploidy level benefits the success of an invasive species, but the basis for this phenomenon is not fully understood. In its native, North American range, Solidago gigantea has three geo-cytotypes comprising di-, tetra- and hexaploid populations, while in Europe, where it is highly invasive, S. gigantea stands are composed primarily of tetraploid individuals. Our study investigates whether North American hexaploids can induce a greater risk of invasion, due to their higher performance in a non-native range, as compared to the existing tetraploids of that range.
Methods We performed greenhouse and common garden experiments along with microsatellite analyses to test whether differences in chromosome number and origin of the species mean superior fitness in the introduced range.
Important findings Genetic diversity was significantly higher in the native hexaploid populations (A R = 6.04; H e = 0.7794), rather than the non-native tetraploid populations (A R = 4.83; H e = 0.6869). Furthermore, differentiation between geo-cytotypes was moderate (ρ ST = 0.1838), which was also confirmed by their clear segregation in principal component analysis and structure analyses, proving their different genetic structure. In contrast to genetic diversity, the non-native tetraploid geo-cytotype performed better in the common garden experiment, implying that higher genetic diversity does not always mean better success. Our results suggest that native hexaploids do not present a greater risk, as assessed by their performance in the introduced range, when compared to the non-native tetraploids, as was suggested by previous studies. Nevertheless, their introduction is still undesirable due to their different genetic structure, which, through hybridization, could give a new drive to the invasion of S. gigantea .

Key words: EICA, plant invasion, microsatellite, ecotype, polyploidy

摘要:
Aims Understanding the role of genetics in biological invasions has become an important aspect for modern plant ecology. Many studies suggest that increased ploidy level benefits the success of an invasive species, but the basis for this phenomenon is not fully understood. In its native, North American range, Solidago gigantea has three geo-cytotypes comprising di-, tetra- and hexaploid populations, while in Europe, where it is highly invasive, S. gigantea stands are composed primarily of tetraploid individuals. Our study investigates whether North American hexaploids can induce a greater risk of invasion, due to their higher performance in a non-native range, as compared to the existing tetraploids of that range.
Methods We performed greenhouse and common garden experiments along with microsatellite analyses to test whether differences in chromosome number and origin of the species mean superior fitness in the introduced range.
Important findings Genetic diversity was significantly higher in the native hexaploid populations (A R = 6.04; H e = 0.7794), rather than the non-native tetraploid populations (A R = 4.83; H e = 0.6869). Furthermore, differentiation between geo-cytotypes was moderate (ρ ST = 0.1838), which was also confirmed by their clear segregation in principal component analysis and structure analyses, proving their different genetic structure. In contrast to genetic diversity, the non-native tetraploid geo-cytotype performed better in the common garden experiment, implying that higher genetic diversity does not always mean better success. Our results suggest that native hexaploids do not present a greater risk, as assessed by their performance in the introduced range, when compared to the non-native tetraploids, as was suggested by previous studies. Nevertheless, their introduction is still undesirable due to their different genetic structure, which, through hybridization, could give a new drive to the invasion of S. gigantea .