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van Mazijk R, West AG, Verboom GA, Elliott TL, Bureš P, Muasya AM. Genome size variation in Cape schoenoid sedges (Schoeneae) and its ecophysiological consequences. AMERICAN JOURNAL OF BOTANY 2024; 111:e16315. [PMID: 38695147 DOI: 10.1002/ajb2.16315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 02/12/2024] [Accepted: 02/12/2024] [Indexed: 08/24/2024]
Abstract
PREMISE Increases in genome size in plants-often associated with larger, low-density stomata and greater water-use efficiency (WUE)-could affect plant ecophysiological and hydraulic function. Variation in plant genome size is often due to polyploidy, having occurred repeatedly in the austral sedge genus Schoenus in the Cape Floristic Region (CFR), while species in the other major schoenoid genus in the region, Tetraria, have smaller genomes. Comparing these genera is useful as they co-occur at the landscape level, under broadly similar bioclimatic conditions. We hypothesized that CFR Schoenus have greater WUE, with lower maximum stomatal conductance (gwmax) imposed by larger, less-dense stomata. METHODS We investigated relationships between genome size and stomatal parameters in a phylogenetic context, reconstructing a phylogeny of CFR-occurring Schoeneae (Cyperaceae). Species' stomatal and functional traits were measured from field-collected and herbarium specimens. Carbon stable isotopes were used as an index of WUE. Genome size was derived from flow-cytometric measurements of leafy shoots. RESULTS Evolutionary regressions demonstrated that stomatal size and density covary with genome size, positively and negatively, respectively, with genome size explaining 72-75% of the variation in stomatal size. Larger-genomed species had lower gwmax and C:N ratios, particularly in culms. CONCLUSIONS We interpret differences in vegetative physiology between the genera as evidence of more-conservative strategies in CFR Schoenus compared to the more-acquisitive Tetraria. Because Schoenus have smaller, reduced leaves, they likely rely more on culm photosynthesis than Tetraria. Across the CFR Schoeneae, ecophysiology correlates with genome size, but confounding sources of trait variation limit inferences about causal relationships between traits.
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Affiliation(s)
- Ruan van Mazijk
- Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
- Bolus Herbarium, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
- C4 EcoSolutions, Tokai, Cape Town, 7945, South Africa
| | - Adam G West
- Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
| | - G Anthony Verboom
- Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
- Bolus Herbarium, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
| | - Tammy L Elliott
- Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
- Bolus Herbarium, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlarska 2, Brno, 611 37, Czech Republic
| | - Petr Bureš
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlarska 2, Brno, 611 37, Czech Republic
| | - A Muthama Muasya
- Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
- Bolus Herbarium, University of Cape Town, Private Bag X3, Rondebosch, Cape Town, 7701, South Africa
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Elliott TL, Muasya AM, Bureš P. Complex patterns of ploidy in a holocentric plant clade (Schoenus, Cyperaceae) in the Cape biodiversity hotspot. ANNALS OF BOTANY 2023; 131:143-156. [PMID: 35226733 PMCID: PMC9904348 DOI: 10.1093/aob/mcac027] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 02/27/2022] [Indexed: 05/24/2023]
Abstract
BACKGROUND AND AIMS It is unclear how widespread polyploidy is throughout the largest holocentric plant family - the Cyperaceae. Because of the prevalence of chromosomal fusions and fissions, which affect chromosome number but not genome size, it can be impossible to distinguish if individual plants are polyploids in holocentric lineages based on chromosome count data alone. Furthermore, it is unclear how differences in genome size and ploidy levels relate to environmental correlates within holocentric lineages, such as the Cyperaceae. METHODS We focus our analyses on tribe Schoeneae, and more specifically the southern African clade of Schoenus. We examine broad-scale patterns of genome size evolution in tribe Schoeneae and focus more intensely on determining the prevalence of polyploidy across the southern African Schoenus by inferring ploidy level with the program ChromEvol, as well as interpreting chromosome number and genome size data. We further investigate whether there are relationships between genome size/ploidy level and environmental variables across the nutrient-poor and summer-arid Cape biodiversity hotspot. KEY RESULTS Our results show a large increase in genome size, but not chromosome number, within Schoenus compared to other species in tribe Schoeneae. Across Schoenus, there is a positive relationship between chromosome number and genome size, and our results suggest that polyploidy is a relatively common process throughout the southern African Schoenus. At the regional scale of the Cape, we show that polyploids are more often associated with drier locations that have more variation in precipitation between dry and wet months, but these results are sensitive to the classification of ploidy level. CONCLUSIONS Polyploidy is relatively common in the southern African Schoenus, where a positive relationship is observed between chromosome number and genome size. Thus, there may be a high incidence of polyploidy in holocentric plants, whose cell division properties differ from monocentrics.
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Affiliation(s)
| | - A Muthama Muasya
- Bolus Herbarium, Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, Cape Town 7701, South Africa
| | - Petr Bureš
- Masaryk University, Faculty of Science, Department of Botany and Zoology, Kotlarska 2, Brno, Czech Republic
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Muasya AM, Larridon I. Delimiting the genera of the Ficinia Clade (Cypereae, Cyperaceae) based on molecular phylogenetic data. PeerJ 2021; 9:e10737. [PMID: 33569253 PMCID: PMC7845527 DOI: 10.7717/peerj.10737] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 12/18/2020] [Indexed: 11/20/2022] Open
Abstract
Generic delimitations in the Ficinia Clade of tribe Cypereae are revisited. In particular, we aim to establish the placement of annual species currently included in Isolepis of which the phylogenetic position is uncertain. Phylogenetic inference is based on two nuclear markers (ETS, ITS) and five plastid markers (the genes matK, ndhF, rbcL and rps16, the trnL intron and trnL-F spacer) data, analyzed using model based methods. Topologies based on nuclear and plastid data show incongruence at the backbone. Therefore, the results are presented separately. The monophyly of the smaller genera (Afroscirpoides, Dracoscirpoides, Erioscirpus, Hellmuthia, Scirpoides) is confirmed. However, Isolepis is paraphyletic as Ficinia is retrieved as one of its clades. Furthermore, Ficinia is paraphyletic if I. marginata and allies are excluded. We take a pragmatic approach based on the nuclear topology, driven by a desire to minimize taxonomic changes, to recircumscribe Ficinia to include the annual Isolepis species characterized by cartilaginous glumes and formally include all the Isolepis species inferred outside the core Isolepis clade. Consequently, the circumscription of Isolepis is narrowed to encompass only those species retrieved as part of the core Isolepis clade. Five new combinations are made (Ficinia neocapensis, Ficinia hemiuncialis, Ficinia incomtula, Ficinia leucoloma, Ficinia minuta). We present nomenclatural summary at genus level, identification keys and diagnostic features.
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Affiliation(s)
- A Muthama Muasya
- Department of Biological Sciences, Bolus Herbarium, University of Cape Town, Rondebosch, Cape Town, South Africa.,Identification and Naming, Royal Botanic Gardens Kew, Richmond, Surrey, UK
| | - Isabel Larridon
- Identification and Naming, Royal Botanic Gardens Kew, Richmond, Surrey, UK.,Department of Biology, Systematic and Evolutionary Botany Lab, Ghent University, Gent, Belgium
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Léveillé-Bourret É, Chen BH, Garon-Labrecque MÈ, Ford BA, Starr JR. RAD sequencing resolves the phylogeny, taxonomy and biogeography of Trichophoreae despite a recent rapid radiation (Cyperaceae). Mol Phylogenet Evol 2020; 145:106727. [DOI: 10.1016/j.ympev.2019.106727] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 12/13/2019] [Accepted: 12/29/2019] [Indexed: 12/15/2022]
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van Santen M, Linder HP. The assembly of the Cape flora is consistent with an edaphic rather than climatic filter. Mol Phylogenet Evol 2020; 142:106645. [DOI: 10.1016/j.ympev.2019.106645] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 10/07/2019] [Accepted: 10/08/2019] [Indexed: 12/14/2022]
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Larridon I, Rabarivola L, Xanthos M, Muasya AM. Revision of the Afro-Madagascan genus Costularia (Schoeneae, Cyperaceae): infrageneric relationships and species delimitation. PeerJ 2019; 7:e6528. [PMID: 30834188 PMCID: PMC6397637 DOI: 10.7717/peerj.6528] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/28/2019] [Indexed: 11/20/2022] Open
Abstract
A recent molecular phylogenetic study revealed four distinct evolutionary lineages in the genus Costularia s.l. (Schoeneae, Cyperaceae, Poales). Two lineages are part of the Oreobolus clade of tribe Schoeneae: the first being a much-reduced genus Costularia s.s., and the second a lineage endemic to New Caledonia for which a new genus Chamaedendron was erected. The other two lineages were shown to be part of the Tricostularia clade of tribe Schoeneae. Based on morphological and molecular data, the genus Costularia is here redelimited to represent a monophyletic entity including 15 species, which is restricted in distribution to southeastern Africa (Malawi, Mozambique, South Africa, Swaziland, Zimbabwe), Madagascar, the Mascarenes (La Réunion, Mauritius), and the Seychelles (Mahé). Molecular phylogenetic data based on two nuclear markers (ETS, ITS) and a chloroplast marker (trnL-F) resolve the studied taxa as monophyletic where multiple accessions could be included (except for Costularia laxa and Costularia purpurea, which are now considered conspecific), and indicate that the genus dispersed once to Africa, twice to the Mascarenes, and once to the Seychelles. Two endemic species from Madagascar are here described and illustrated as new to science, as is one additional species endemic to La Réunion. Two taxa previously accepted as varieties of Costularia pantopoda are here recognised at species level (Costularia baronii and Costularia robusta). We provide a taxonomic revision including an identification key, species descriptions and illustrations, distribution maps and assessments of conservation status for all species.
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Affiliation(s)
- Isabel Larridon
- Identification and Naming, Royal Botanic Gardens, Kew, Richmond, Surrey, UK.,Deparment of Biology, Systematic and Evolutionary Botany Lab, Ghent University, Gent, Belgium
| | | | - Martin Xanthos
- Identification and Naming, Royal Botanic Gardens, Kew, Richmond, Surrey, UK
| | - A Muthama Muasya
- Department of Biological Sciences, Bolus Herbarium, University of Cape Town, Rondebosch, South Africa
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Larridon I, Bauters K, Semmouri I, Viljoen JA, Prychid CJ, Muasya AM, Bruhl JJ, Wilson KL, Senterre B, Goetghebeur P. Molecular phylogenetics of the genus Costularia (Schoeneae, Cyperaceae) reveals multiple distinct evolutionary lineages. Mol Phylogenet Evol 2018; 126:196-209. [PMID: 29679713 DOI: 10.1016/j.ympev.2018.04.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 02/09/2018] [Accepted: 04/09/2018] [Indexed: 12/01/2022]
Abstract
We investigated the monophyly of Costularia (25 species), a genus of tribe Schoeneae (Cyperaceae) that illustrates a remarkable distribution pattern from southeastern Africa, over Madagascar, the Mascarenes and Seychelles, to Malesia and New Caledonia. A further species, Tetraria borneensis, has been suggested to belong to Costularia. Relationships and divergence times were inferred using an existing four marker phylogeny of Cyperaceae tribe Schoeneae expanded with newly generated sequence data mainly for Costularia s.l. species. Phylogenetic reconstruction was executed using Bayesian inference and maximum likelihood approaches. Divergence times were estimated using a relaxed molecular clock model, calibrated with fossil data. Based on our results, Tetraria borneensis is not related to the species of Costularia. Costularia s.l. is composed of four distinct evolutionary lineages. Two lineages, one including the type species, are part of the Oreobolus clade, i.e. a much reduced genus Costularia restricted to southeastern Africa, Madagascar, the Mascarenes and Seychelles, and a small endemic genus from New Caledonia for which a new genus Chamaedendron is erected based on Costularia subgenus Chamaedendron. The other two lineages are part of the Tricostularia clade, i.e. a separate single-species lineage from the Seychelles for which a new genus (Xyroschoenus) is described, and Costularia subgenus Lophoschoenus. For the latter, more research is needed to test whether they are congeneric with the species placed in the reticulate-sheathed Tetraria clade.
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Affiliation(s)
- Isabel Larridon
- Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AE, UK; Ghent University, Department of Biology, Research Group Spermatophytes, K.L. Ledeganckstraat 35, 9000 Gent, Belgium.
| | - Kenneth Bauters
- Ghent University, Department of Biology, Research Group Spermatophytes, K.L. Ledeganckstraat 35, 9000 Gent, Belgium; Botanic Garden Meise, Nieuwelaan 38, 1860 Meise, Belgium
| | - Ilias Semmouri
- Ghent University, Department of Biology, Research Group Spermatophytes, K.L. Ledeganckstraat 35, 9000 Gent, Belgium; Ghent University, Faculty of Bioscience Engineering, Laboratory of Environmental Toxicology and Aquatic Ecology, 9000 Gent, Belgium
| | | | | | - A Muthama Muasya
- University of Cape Town, Department of Biological Sciences, Bolus Herbarium, Private Bag X3, Rondebosch 7701, South Africa
| | - Jeremy J Bruhl
- University of New England, School of Environmental and Rural Science, Armidale, New South Wales 2351, Australia
| | - Karen L Wilson
- National Herbarium of New South Wales, Royal Botanic Gardens and Domain Trust, Sydney, New South Wales 2000, Australia
| | - Bruno Senterre
- Island Biodiversity & Conservation Centre, University of Seychelles, P.O. Box 1348, Anse Royale, Mahé, Seychelles; Université Libre de Bruxelles, Evolutionary Biology & Ecology, CP 160/12, 50 Av. F. Roosevelt, 1050 Bruxelles, Belgium
| | - Paul Goetghebeur
- Ghent University, Department of Biology, Research Group Spermatophytes, K.L. Ledeganckstraat 35, 9000 Gent, Belgium
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Maguilla E, Escudero M, Hipp AL, Luceño M. Allopatric speciation despite historical gene flow: Divergence and hybridization in Carex furva and C. lucennoiberica (Cyperaceae) inferred from plastid and nuclear RAD-seq data. Mol Ecol 2017; 26:5646-5662. [PMID: 28742230 DOI: 10.1111/mec.14253] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 06/29/2017] [Accepted: 06/30/2017] [Indexed: 12/13/2022]
Abstract
Gene flow among incipient species can act as a creative or destructive force in the speciation process, generating variation on which natural selection can act while, potentially, undermining population divergence. The flowering plant genus Carex exhibits a rapid and relatively recent radiation with many species limits still unclear. This is the case with the Iberian Peninsula (Spain and Portugal)-endemic C. lucennoiberica, which lay unrecognized within Carex furva until its recent description as a new species. In this study, we test how these species were impacted by interspecific gene flow during speciation. We sampled the full range of distribution of C. furva (15 individuals sampled) and C. lucennoiberica (88 individuals), sequenced two cpDNA regions (atpI-atpH, psbA-trnH) and performed genomic sequencing of 45,100 SNPs using restriction site-associated DNA sequencing (RAD-seq). We utilized a set of partitioned D-statistic tests and demographic analyses to study the degree and direction of introgression. Additionally, we modelled species distributions to reconstruct changes in range distribution during glacial and interglacial periods. Plastid, nuclear and morphological data strongly support divergence between species with subsequent gene flow. Combined with species distribution modelling, these data support a scenario of allopatry leading to species divergence, followed by secondary contact and gene flow due to long-distance dispersal and/or range expansions and contractions in response to Quaternary glacial cycles. We conclude that this is a case of allopatric speciation despite historical secondary contacts, which could have temporally influenced the speciation process, contributing to the knowledge of forces that are driving or counteracting speciation.
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Affiliation(s)
| | - Marcial Escudero
- Departamento de Biología Vegetal y Ecología, Universidad de Sevilla, Seville, Spain
| | - Andrew L Hipp
- The Morton Arboretum, Lisle, IL, USA.,Botany Department, Field Museum of Natural History, Chicago, IL, USA
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Distribution and Evolution of Mycorrhizal Types and Other Specialised Roots in Australia. BIOGEOGRAPHY OF MYCORRHIZAL SYMBIOSIS 2017. [DOI: 10.1007/978-3-319-56363-3_17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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A new delimitation of the Afro-Eurasian plant genus Althenia to include its Australasian relative, Lepilaena (Potamogetonaceae) – Evidence from DNA and morphological data. Mol Phylogenet Evol 2016; 98:261-70. [DOI: 10.1016/j.ympev.2016.02.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 02/01/2016] [Accepted: 02/01/2016] [Indexed: 12/31/2022]
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Spalink D, Drew BT, Pace MC, Zaborsky JG, Li P, Cameron KM, Givnish TJ, Sytsma KJ. Evolution of geographical place and niche space: Patterns of diversification in the North American sedge (Cyperaceae) flora. Mol Phylogenet Evol 2016; 95:183-95. [DOI: 10.1016/j.ympev.2015.09.028] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 09/10/2015] [Accepted: 09/17/2015] [Indexed: 11/15/2022]
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