Early diverging and core Bromelioideae (Bromeliaceae) reveal contrasting patterns of genome size evolution and polyploidy

  • The subfamily Bromelioideae is one of the most diverse groups among the neotropical Bromeliaceae. Previously, key innovations have been identified which account for the extraordinary radiation and species richness of this subfamily, especially in the so-called core Bromelioideae. However, in order to extend our understanding of the evolutionary mechanisms, the genomic mechanisms (e.g. polyploidy, dysploidy) that potentially underlie this accelerated speciation also need to be tested. Here, using PI and DAPI staining and flow cytometry we estimated genome size and GC content of 231 plants covering 30 genera and 165 species and combined it with published data. The evolutionary and ecological significance of all three genomic characters was tested within a previously generated dated phylogenetic framework using ancestral state reconstructions, comparative phylogenetic methods, and multiple regressions with climatic variables. The absolute genome size (2C) of Bromelioideae varied between 0.59 and 4.11 pg, and the GC content ranged between 36.73 and 41.43%. The monoploid genome sizes (Cx) differed significantly between core and early diverging lineages. The occurrence of dysploidy and polyploidy was, with few exceptions, limited to the phylogenetically isolated early diverging tank-less lineages. For Cx and GC content Ornstein–Uhlenbeck models outperformed the Brownian motion models suggesting adaptive potential linked to the temperature conditions. 2C-values revealed different rates of evolution in core and early diverging lineages also related to climatic conditions. Our results suggest that polyploidy is not associated with higher net diversification and fast radiation in core bromelioids. On the other hand, although coupled with higher extinction rates, dysploidy, polyploidy, and resulting genomic reorganizations might have played a role in the survival of the early diverging bromelioids in hot and arid environments.
Author:Juraj PauleORCiDGND, Sascha Heller, Jefferson Rodrigues Maciel, Raquel F. Monteiro, Elton M. C. Leme, Georg ZizkaORCiDGND
Parent Title (English):Frontiers in plant science
Publisher:Frontiers Media
Place of publication:Lausanne
Document Type:Article
Date of Publication (online):2020/09/09
Date of first Publication:2020/09/09
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2020/10/07
Tag:C-value; GC content; bromeliads; chromosome number; climate; flow cytometry; phylogenetic signal; ploidy
Issue:art. 1295
Page Number:13
First Page:1
Last Page:13
© 2020 Paule, Heller, Maciel, Monteiro, Leme and Zizka. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Institutes:Biowissenschaften / Institut für Ökologie, Evolution und Diversität
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 58 Pflanzen (Botanik) / 580 Pflanzen (Botanik)
Licence (German):License LogoCreative Commons - Namensnennung 4.0