Origin and genetic variation of tree of heaven in Eastern Austria, an area of early introduction

Transcription

1 Institute of Silviculture University of Natural Resources and Life Sciences (BOKU), Vienna Origin and genetic variation of tree of heaven in Eastern Austria, an area of early introduction Vienna, Charalambos Neophytou 1, Elisabeth Pötzelsberger 1, Manuel Curto 2, Harald Meimberg 2, Hubert Hasenauer 1 1 Institute of Silviculture University of Natural Resources and Life Sciences (BOKU), Vienna 2 Institute for Integrative Nature Conservation Research University of Natural Resources and Life Sciences (BOKU), Vienna

2 Outline Tree of heaven: Origin, introduction to Europe and Austria Genetic analysis of heaven tree in E Austria Area of origin in the native range Genetic diversity within populations Vegetative recruitment and clone extent Genetic differentiation across populations What does the genetic analysis tell us about the history of introduction of the tree of heaven and its evolution in its non-native range? 2

3 Tree of heaven (Ailanthus altissima (Miller) Swingle): A new resident of European forests Origin: Eastern China: north to the area of Beijing, east to the coast, west to the Eastern Himalayas, south to Northern Vietnam Properties: Insect pollinated, dioecious, light demanding, pioneer, vegetative reproduction by root suckers Introduction to Europe: 1740 by a French missionary (seeds sent from Beijing to Paris * ) Native range mapped by E. J. Jäger & E. Welk, AG Chorology, Institute for Biology Halle/Saale published in Kowarik & Säumel (2007) Pl. Ecol. Evol. Sys. 8, Initially, it was planted for aesthetic reasons, but soon also for other uses. * = Hu, S. Y. (1979). Ailanthus. Arnoldia, 39(2),

4 Tree of heaven (Ailanthus altissima (Miller) Swingle): A new resident of European forests Vienna, AT Photos: Ch. Neophytou Nicosia, CY Non-native range mapped by E. J. Jäger & E. Welk, AG Chorology, Institute for Biology Halle/Saale published in Kowarik & Säumel (2007) Pl. Ecol. Evol. Sys. 8, Expansion in Europe: 18 th century: Plantations e.g. for sand-dune stabilization, windbreaks, for silkworm feeding Spontaneous spread from sites of plantation mostly into certain urban, rural or forest sites Hochleithenwald, AT 4

5 Introduction of heaven tree to Austria First reports: end of 18th century Uses: stabilization of sand dunes, shelter belts / windbreaks, silk production, carpentry, park tree, tree alleys Märter FJ (1796). Verzeichniß der österreichischen Bäume und Sträucher. Stahel, Wien Pesenböck (1864) Allgemeine Land- und forstwirtschaftliche Zeitung Anonymous 1882, View of the Austrian Parliament. Source: Austrian National Library 5

6 Study area and sampled forest stands Study area: Eastern Austria, mainly forest ecoregion 8.1, where most occurrences have been observed. Questions and methods: Native origin 3 chloroplast DNA (cpdna) markers 1,2 Vegetative reproduction, genetic structure and diversity use of 17 microsatellite (nussr) markers 2,3,4 10 study populations with 30 sampled trees each (systematic sampling) 1 Liao et al. (2014), J. Sys. Evol 52, Neophytou et al. (2018), Forestry (in revision) 3 Dallas et al. (2005), Mol. Ecol. Notes 5, Neophytou et al. (2018), Tree Genet. Genomes (under review) Maps: E. Pötzelsberger (above) Ch. Neophytou (below) 6

7 One single origin found in all populations Comparison of cpdna-haplotypes with the native range One single haplotype (haplotype 7) was found in all 10 populations in Eastern Austria. Haplotype 7 is common in the NE part of the native range including Beijing area where the first seeds sent to Europe (in 1740) originated from Map from: Liao, Y.Y., Guo, Y.H., Chen, J.M., & Wang, Q.F. (2014) Phylogeography of the widespread plant Ailanthus altissima (Simaroubaceae) in China indicated by three chloroplast DNA regions. Journal of Systematics and Evolution, 52(2), Probably, Austrian heaven trees are ancestors of the first trees planted with those seeds Should we expect a highly uniform gene pool? 7

8 Genetic analysis within populations reveals clonal structures Measures of genetic diversity based on 17 nuclear microsatellites Population name N N G N a H o H e F IS AR 3 Osterburg (± 0.22) 0.59 (± 0.06) 0.51 (± 0.04) (n.s.) 2.34 (± 0.25) Brunnkirchen (± 0.38) 0.60 (± 0.06) 0.58 (± 0.04) (n.s.) 2.70 (± 0.35) Utzenlaa (± 0.24) 0.63 (± 0.05) 0.61 (± 0.02) (n.s.) 2.68 (± 0.23) Wolkersdorf (± 0.45) 0.60 (± 0.06) 0.58 (± 0.04) (n.s.) 2.72 (± 0.37) Matzen (± 0.34) 0.57 (± 0.05) 0.59 (± 0.03) (n.s.) 2.80 (± 0.32) Weikendorf (± 0.30) 0.59 (± 0.05) 0.59 (± 0.03) (n.s.) 2.76 (± 0.24) Obersiebenbrunn (± 0.26) 0.66 (± 0.09) 0.55 (± 0.04) (n.s.) 2.72 (± 0.56) Leithaprodersdorf (± 0.32) 0.67 (± 0.06) 0.60 (± 0.04) * 2.77 (± 0.41) Donnerskirchen (± 0.42) 0.65 (± 0.05) 0.65 (± 0.03) (n.s.) 3.01 (± 0.30) Herrnbaumgarten (± 0.35) 0.62 (± 0.07) 0.54 (± 0.04) * 2.48 (± 0.39) Not all sampled trees possessed unique genotypes Is this the result of vegetative reproduction? N = number of individuals N G = number of unique genotypes N a = mean number of alleles per locus and individual H o = observed heterozygosity H e = expected heterozygosity F IS = fixation index AR 3 = allelic richness with rarefaction (rarefaction size = 3 diploid genotypes) 8

9 Das Bild kann zurzeit nicht angezeigt werden. Das Bild kann zurzeit nicht angezeigt werden. Expansion though root-suckers in areas of early introduction? Population name N N G N CL d max R Osterburg Brunnkirchen Utzenlaa Wolkersdorf Matzen Weikendorf Obersiebenbrunn Leithaprodersdorf Donnerskirchen Herrnbaumgarten High clonality in areas of early introduction Hypothesis: clone expansion took place through repeated cycles of vegetative reproduction 9

10 High genetic variability within populations Measures of genetic diversity based on 17 nussrs Population name N N G N a H o H e F IS AR 3 Osterburg (± 0.22) 0.59 (± 0.06) 0.51 (± 0.04) (n.s.) 2.34 (± 0.25) Brunnkirchen (± 0.38) 0.60 (± 0.06) 0.58 (± 0.04) (n.s.) 2.70 (± 0.35) Utzenlaa (± 0.24) 0.63 (± 0.05) 0.61 (± 0.02) (n.s.) 2.68 (± 0.23) Wolkersdorf (± 0.45) 0.60 (± 0.06) 0.58 (± 0.04) (n.s.) 2.72 (± 0.37) Matzen (± 0.34) 0.57 (± 0.05) 0.59 (± 0.03) (n.s.) 2.80 (± 0.32) Weikendorf (± 0.30) 0.59 (± 0.05) 0.59 (± 0.03) (n.s.) 2.76 (± 0.24) Obersiebenbrunn (± 0.26) 0.66 (± 0.09) 0.55 (± 0.04) (n.s.) 2.72 (± 0.56) Leithaprodersdorf (± 0.32) 0.67 (± 0.06) 0.60 (± 0.04) * 2.77 (± 0.41) Donnerskirchen (± 0.42) 0.65 (± 0.05) 0.65 (± 0.03) (n.s.) 3.01 (± 0.30) Herrnbaumgarten (± 0.35) 0.62 (± 0.07) 0.54 (± 0.04) * 2.48 (± 0.39) High variability, excess of heterozygotes Is there evidence of a recent bottleneck? N = number of individuals N G = number of unique genotypes N a = mean number of alleles per locus and individual H o = observed heterozygosity H e = expected heterozygosity F IS = fixation index AR 3 = allelic richness with rarefaction (rarefaction size = 3 diploid genotypes) 10

11 Data suggest recent bottlenecks Tests for recent bottleneck 1,2 based on data from 17 nussrs Population name Number of loci with heterozygosity excess Sign test prob. Two-tailed Wilcoxon-test prob. Observed Expected Osterburg Brunnkirchen Utzenlaa Wolkersdorf Matzen Weikendorf Obersiebenbrunn Leithaprodersdorf Donnerskirchen Herrnbaumgarten Both tests for bottleneck were significant in almost all populations 1 Cornuet & Luikart (1996), Genetics 144, Piry et al. (1999), J. Hered. 90, Bottleneck has shaped the gene pool of Ailanthus altissima in E Austria 11

12 Populations are genetically highly differentiated from each other Genetic differentiation based on 17 nussrs F ST -based UPGMA dendrogram Bayesian clustering analysis (STRUCTURE) 1,2 Global F ST = 0.11 (P < 0.001) No isolation by distance 1 Pritchard et al. (2000), Genetics 155, Falush et al. (2003), Genetics 164, Results presented in: Neophytou et al. (2018), Forestry (in revision) 12

13 Das Bild kann zurzeit nicht angezeigt werden. Genetic differentiation might have occurred after introduction The genetic differentiation might have occurred after introduction, since the origin is common. Bottlenecks might have played a significant role. No isolation by distance (no correlation between geographic and genetic distance) Seed transfer might have also influenced the genetic variation of Ailanthus altissima in Eastern Austria. 13

14 Summary and conclusions (1) Only one origin agreeing with the area where the first seeds sent to Europe originated from: Extant populations in E Austria probably ancestors of the first introduced trees Later introductions from other areas of the native range unlikely 14

15 Summary and conclusions (2) Vegetative reproduction led to extensive clonal structures at some places: Pattern more common in areas of early introduction Several cycles of vegetative recruitment might have led to the expansion of these structures in such areas 15

16 Summary and conclusions (3) In spite of a single origin, genetic differentiation among stands is high and significant: Lack of isolation-by-distance seed transfer Bottleneck might have resulted in a high genetic differentiation 16

17 Acknowledgements 17