Molecular phylogenetics shed light on polyploid speciation in gorses (Ulex, Fabaceae: Genisteae) and on the origin of the invasive Ulex europaeus.
Resource type
Journal article
Date published
May 1, 2023
Abstract
Hybridization and polyploidy are key evolutionary forces in plant diversification, and their co-occurrence in the context of allopolyploid speciation is often associated with increased ability to colonize new environments and invasiveness. In the genus Ulex (Fabaceae), the European gorse (Ulex europaeus subsp. europaeus) is the only invasive and the only polyploid that has recently spread in different eco-geographical regions across the world. Understanding what confers such ecological advantages to this species, compared to its diploid and polyploid congeners, first requires clarification of the ecogeographical and evolutionary context of its formation. To achieve this, the geographical distributions of all Ulex spp. were estimated from species occurrence records, and phylogenetic analyses including all Ulex spp. were performed based on four nuclear (ITS and ETS nrDNA) and plastid (rps12 intron and trnK-matK) regions. The resulting trees were dated using a secondary calibration. Patterns of DNA sequence variation and dated phylogenetic trees were then interpreted in light of previous knowledge of chromosome numbers in Ulex to infer past events of polyploid speciation in the genus. We show that: (1) most current Ulex spp. radiated in the Iberian Peninsula during the past 1–2 Myr; (2) the history of Ulex was punctuated by multiple whole-genome duplication events; and (3) U. europaeus subsp. europaeus is the only gorse taxon that was formed by hybridization of two well-differentiated lineages (which separated c. 5 Mya) with wide climatic ranges (currently represented by Ulex minor and Ulex europaeus subsp. latebracteatus), possibly contributing to the invasive nature and wider climatic range of U. europaeus subsp. europaeus. These findings provide a much-needed evolutionary framework in which to explore the adaptive consequences of genome mergers and duplication in Ulex.
Project(s)
Priority 2: Trait Diversity and Function
Funder
| Funder name | Awards |
Université de Rennes 1, France | UMR-CNRS 6553 Ecobio |
Centre National de la Recherche Scientifique, France | International Associated Laboratory ‘Ecological Genomics of Polyploidy’, UMR-CNRS 6553 Ecobio |
Journal title
Botanical Journal of the Linnean Society
Volume
202
Issue
1
Publisher
Oxford University Press (OUP)
Place of publication
Oxford, UK
ISSN
0024-4074
eISSN
1095-8339
Date accepted
October 26, 2022
Official URL
Rights statement
In Copyright
Additional information
IF = 2.828 (2022-2023)