Abstract Detail


Nuppenau, Jan-Niklas [1], Höglund, Elsa  [1], Kent , Kainulainen [2], Minadakis, Nikolaos [3], Wikström, Niklas [1], Humphreys, Aelys,M. [1].

Population structure and colonisation history of Icelandic Agrostis from geothermally heated and non-heated areas.

Geothermally heated areas offer a special opportunity to study how plant populations react to changing environmental conditions. Individuals growing on these soils spend their life under very contrasting conditions compared to surrounding populations.  The genus Agrostis (Poaceae) is well known to easily form ecotypes in response to special edaphic conditions, such as old mining sides.  On Iceland Agrostis species are able to grow on heated soils which reach up to 90 °C at 10 cm depth. Having Agrostis species growing in geothermal areas, which are special in their edaphic as well as their temperature properties, represents a unique system for studying processes of local adaptation. The aim of  this study was  to find out if populations from heated soils are genetically distinct from non-heated populations and were they came from. We hypothesized that Iceland was colonized once from nearby northern populations and then diverged into genetically distinct heated and non-heated populations. To investigate the population structure and history of Agrostis populations on Iceland, an extensive phylogeny was built using whole chloroplast data.  On Iceland three different species of Agrostis: A. capillaris, A. stolonifera and A. vinealis grown on heated soils. Plant material for these species was collected for individuals from heated and non-heated populations from across Iceland, as well as across each species’ worldwide distribution range. Bayesian analyses, treating the whole chloroplast as a single partition, show that for A. vinealis  and A. capillaris all Icelandic populations are in one clade together with accessions from nearby areas such as Norway and Great Britain , without any population structure within. However, A. stolonifera populations, from the most extreme heated sites, form a strongly supported monophyletic clade, which is closely related to more southern accessions from Spain and Greece.  All other A. stolonifera populations from Iceland fall into a large boreal clade, together with accessions from Norway and Greenland. The complete intermixture of A. vinealis and A. capillaris populations indicates a strong gene flow among populations and no specially adapted geothermal lineage. Agrostis stolonifera on the other hand might have colonized Iceland twice, where a potentially more heat tolerant lineage colonized the geothermal soils and not much gene exchange occurred afterwards. The findings of this study highlight the peculiarity of geothermal systems and open the door for future investigations on genetic differences, as well as for experimental work on e.g. temperature tolerances and phenological differences, of these grasses.    

1 - Stockholm University, ecology, environment and plant science, Svante Arrhenius väg 20 A , 114 18 Stockholm, Stockholm, Sweden
2 - Gothenburg Botanical Garden, Carl Skottsbergs gata 22A, 413 19 Göteborg, Gothenburg, Sweden
3 - University of Zürich, Department of Plant and Microbial Biology, Zollikerstrasse 107, CH-8008 Zürich, Zürich, Switzerland

Local Adaptation
extreme conditions
geothermal soils
colonisation history
population structure.

Presentation Type: Poster
Session: P, Biogeography Posters
Location: Virtual/Virtual
Date: Monday, July 27th, 2020
Time: 5:00 PM Time and date to be determined
Number: PBG011
Abstract ID:685
Candidate for Awards:None

Copyright © 2000-2020, Botanical Society of America. All rights reserved