Hybridisation and chloroplast capture between distinct Themeda triandra lineages in Australia.

Autor: Dunning LT; Ecology and Evolutionary Biology, School of Biosciences, University of Sheffield, Sheffield, UK., Olofsson JK; Section for Forest, Nature and Biomass, Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg C, Denmark., Papadopulos AST; Molecular Ecology and Evolution, Bangor University, Environment Centre for Wales, Bangor, UK., Hibdige SGS; Ecology and Evolutionary Biology, School of Biosciences, University of Sheffield, Sheffield, UK., Hidalgo O; Royal Botanic Gardens, Surrey, UK.; Institut Botànic de Barcelona (IBB), CSIC-Ajuntament de Barcelona, Barcelona, Spain., Leitch IJ; Royal Botanic Gardens, Surrey, UK., Baleeiro PC; Department of Biological Science, The University of Queensland, St Lucia, Queensland, Australia., Ntshangase S; Department of Plant and Soil Sciences, University of Pretoria, Hatfield, South Africa., Barker N; Department of Plant and Soil Sciences, University of Pretoria, Hatfield, South Africa., Jobson RW; National Herbarium of New South Wales, Australian Institute of Botanical Science, Sydney, New South Wales, Australia.
Jazyk: angličtina
Zdroj: Molecular ecology [Mol Ecol] 2022 Nov; Vol. 31 (22), pp. 5846-5860. Date of Electronic Publication: 2022 Sep 27.
DOI: 10.1111/mec.16691
Abstrakt: Ecotypes are distinct populations within a species that are adapted to specific environmental conditions. Understanding how these ecotypes become established, and how they interact when reunited, is fundamental to elucidating how ecological adaptations are maintained. This study focuses on Themeda triandra, a dominant grassland species across Asia, Africa and Australia. It is the most widespread plant in Australia, where it has distinct ecotypes that are usually restricted to either wetter and cooler coastal regions or the drier and hotter interior. We generate a reference genome for T. triandra and use whole genome sequencing for over 80 Themeda accessions to reconstruct the evolutionary history of T. triandra and related taxa. Organelle phylogenies confirm that Australia was colonized by T. triandra twice, with the division between ecotypes predating their arrival in Australia. The nuclear genome provides evidence of differences in the dominant ploidal level and gene-flow among the ecotypes. In northern Queensland there appears to be a hybrid zone between ecotypes with admixed nuclear genomes and shared chloroplast haplotypes. Conversely, in the cracking claypans of Western Australia, there is cytonuclear discordance with individuals possessing the coastal chloroplast and interior clade nuclear genome. This chloroplast capture is potentially a result of adaptive introgression, with selection detected in the rpoC2 gene which is associated with water use efficiency. The reason that T. triandra is the most widespread plant in Australia appears to be a result of distinct ecotypic genetic variation and genome duplication, with the importance of each depending on the geographic scale considered.
(© 2022 The Authors. Molecular Ecology published by John Wiley & Sons Ltd.)
Databáze: MEDLINE
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