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Wefferling KM, Castro M, Castro S, Holmlund H, Loureiro J, Rothfels CJ, Schuettpelz E. Polyploid goldback and silverback ferns (Pentagramma) occupy a wider, colder, and wetter bioclimatic niche than diploid counterparts. AMERICAN JOURNAL OF BOTANY 2024; 111:e16305. [PMID: 38517199 DOI: 10.1002/ajb2.16305] [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: 08/22/2023] [Revised: 01/22/2024] [Accepted: 01/22/2024] [Indexed: 03/23/2024]
Abstract
PREMISE The western North American fern genus Pentagramma (Pteridaceae) is characterized by complex patterns of ploidy variation, an understanding of which is critical to comprehending both the evolutionary processes within the genus and its current diversity. METHODS We undertook a cytogeographic study across the range of the genus, using a combination of chromosome counts and flow cytometry to infer ploidy level. Bioclimatic variables and elevation were used to compare niches. RESULTS We found that diploids and tetraploids are common and widespread, and triploids are rare and sporadic; in contrast with genome size inferences in earlier studies, no hexaploids were found. Diploids and tetraploids show different geographic ranges: only tetraploids were found in the northernmost portion of the range (Washington, Oregon, and British Columbia) and only diploids were found in the Sierra Nevada of California. Diploid, triploid, and tetraploid cytotypes were found to co-occur in relatively few localities: in the southern (San Diego County, California) and desert Southwest (Arizona) parts of the range, and along the Pacific Coast of California. CONCLUSIONS Tetraploids occupy a wider bioclimatic niche than diploids both within P. triangularis and at the genus-wide scale. It is unknown whether the wider niche of tetraploids is due to their expansion upon the diploid niche, if diploids have contracted their niche due to competition or changing abiotic conditions, or if this wider niche occupancy is due to multiple origins of tetraploids.
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Affiliation(s)
- Keir M Wefferling
- Department of Biology, Gary A. Fewless Herbarium, Cofrin Center for Biodiversity, University of Wisconsin-Green Bay, Green Bay, 54311, Wisconsin, USA
| | - Mariana Castro
- Department of Life Sciences, Centre for Functional Ecology, University of Coimbra, Coimbra, Portugal
| | - Sílvia Castro
- Department of Life Sciences, Centre for Functional Ecology, University of Coimbra, Coimbra, Portugal
| | - Helen Holmlund
- Natural Science Division, Pepperdine University, Malibu, 90263, California, USA
| | - João Loureiro
- Department of Life Sciences, Centre for Functional Ecology, University of Coimbra, Coimbra, Portugal
| | - Carl J Rothfels
- Department of Biology, Ecology Center, and Intermountain Herbarium, Utah State University, Logan, 84322, Utah, USA
| | - Eric Schuettpelz
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, 20560, DC, USA
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Paczesniak D, Pellino M, Goertzen R, Guenter D, Jahnke S, Fischbach A, Lovell JT, Sharbel TF. Seed size, endosperm and germination variation in sexual and apomictic Boechera. FRONTIERS IN PLANT SCIENCE 2022; 13:991531. [PMID: 36466233 PMCID: PMC9716183 DOI: 10.3389/fpls.2022.991531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/26/2022] [Indexed: 06/17/2023]
Abstract
Asexual reproduction results in offspring that are genetically identical to the mother. Among apomictic plants (reproducing asexually through seeds) many require paternal genetic contribution for proper endosperm development (pseudogamous endosperm). We examined phenotypic diversity in seed traits using a diverse panel of sexual and apomictic accessions from the genus Boechera. While genetic uniformity resulting from asexual reproduction is expected to reduce phenotypic diversity in seeds produced by apomictic individuals, pseudogamous endosperm, variable endosperm ploidy, and the deviations from 2:1 maternal:paternal genome ratio in endosperm can all contribute to increased phenotypic diversity among apomictic offspring. We characterized seed size variation in 64 diploid sexual and apomictic (diploid and triploid) Boechera lineages. In order to find out whether individual seed size was related to endosperm ploidy we performed individual seed measurements (projected area and mass) using the phenoSeeder robot system and flow cytometric seed screen. In order to test whether individual seed size had an effect on resulting fitness we performed a controlled growth experiment and recorded seedling life history traits (germination success, germination timing, and root growth rate). Seeds with triploid embryos were 33% larger than those with diploid embryos, but no average size difference was found between sexual and apomictic groups. We identified a maternal effect whereby chloroplast lineage 2 had 30% larger seeds than lineage 3, despite having broad and mostly overlapping geographic ranges. Apomictic seeds were not more uniform in size than sexual seeds, despite genetic uniformity of the maternal gametophyte in the former. Among specific embryo/endosperm ploidy combinations, seeds with tetraploid (automomous) endosperm were on average smaller, and the proportion of such seeds was highest in apomicts. Larger seeds germinated more quickly than small seeds, and lead to higher rates of root growth in young seedlings. Seed mass is under balancing selection in Boechera, and it is an important predictor of several traits, including germination probability and timing, root growth rates, and developmental abnormalities in apomictic accessions.
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Affiliation(s)
- Dorota Paczesniak
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
- Breeding Research, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Marco Pellino
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
- Breeding Research, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Richard Goertzen
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
| | - Devan Guenter
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
| | - Siegfried Jahnke
- Forschungszentrum Jülich, Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Jülich, Germany
| | - Andreas Fischbach
- Forschungszentrum Jülich, Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Jülich, Germany
| | - John T. Lovell
- Breeding Research, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Timothy F. Sharbel
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
- Breeding Research, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
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Chao YS, Ebihara A, Chiou WL, Tsai JM, Huang YW, Ranker TA. Reticulate evolution in the Pteris fauriei group (Pteridaceae). Sci Rep 2022; 12:9145. [PMID: 35650209 PMCID: PMC9159987 DOI: 10.1038/s41598-022-11390-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 04/14/2022] [Indexed: 11/10/2022] Open
Abstract
The Pteris fauriei group (Pteridaceae) has a wide distribution in Eastern Asia and includes 18 species with similar but varied morphology. We collected more than 300 specimens of the P. fauriei group and determined ploidy by flow cytometry and inferred phylogenies by molecular analyses of chloroplast and nuclear DNA markers. Our results reveal a complicated reticulate evolution, consisting of seven parental taxa and 58 hybrids. The large number of hybrid taxa have added significant morphological complexity to the group leading to difficult taxonomic issues. The hybrids generally had broader ranges and more populations than their parental taxa. Genetic combination of different pairs of parental species created divergent phenotypes of hybrids, exhibited by both morphological characteristics and ecological fidelities. Niche novelty could facilitate hybrid speciation. Apogamy is common in this group and potentially contributes to the sustainability of the whole group. We propose that frequent hybridizations among members of the P. fauriei group generate and maintain genetic diversity, via novel genetic combinations, niche differentiation, and apogamy.
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Affiliation(s)
- Yi-Shan Chao
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, 100, Shih-Chuan 1st Rd., Kaohsiung, 80708, Taiwan.
| | - Atsushi Ebihara
- Department of Botany, National Museum of Nature and Science, 4-1-1, Amakubo, Tsukuba-shi, Ibaraki, 305-0005, Japan
| | - Wen-Liang Chiou
- Taiwan Forestry Research Institute, 53 Nan-Hai Rd., Taipei, 100051, Taiwan
| | - Jer-Min Tsai
- Department of Information and Communication, Kun Shan University, 195, Kunda Rd., Tainan, 710303, Taiwan
| | - Yu-Wen Huang
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, 100, Shih-Chuan 1st Rd., Kaohsiung, 80708, Taiwan
| | - Tom A Ranker
- University of Hawai'i at Mānoa, School of Life Sciences, Honolulu, HI, 96822, USA
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Picard KT, Ranft H, Grusz AL, Windham MD, Schuettpelz E. When it only takes one to tango: assessing the impact of apomixis in the fern genus Pteris. AMERICAN JOURNAL OF BOTANY 2021; 108:2220-2234. [PMID: 34618360 PMCID: PMC9298017 DOI: 10.1002/ajb2.1761] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 07/30/2021] [Accepted: 08/12/2021] [Indexed: 05/14/2023]
Abstract
PREMISE Apomixis (asexual reproduction by seed, spore, or egg) has evolved repeatedly across the tree of life. Studies of animals and angiosperms show that apomictic lineages are often evolutionarily short-lived and frequently exhibit different distributions than their sexual relatives. However, apomixis is rare in these groups. Less is known about the role of apomixis in the evolution and biogeography of ferns, in which ~10% of species are apomictic. Apomixis is especially common in the fern genus Pteris (34-39% of species); however, because of the limited taxonomic and geographic sampling of previous studies, the true frequency of apomixis and its associations with geography and phylogeny in this lineage remain unclear. METHODS We used spore analyses of herbarium specimens to determine reproductive mode for 127 previously unsampled Pteris species. Then we leveraged biogeographic and phylogenetic analyses to estimate the global distribution and evolution of apomixis in Pteris. RESULTS Among all Pteris species examined, we found that 21% are exclusively apomictic, 71% are exclusively sexual, and 8% have conflicting reports. Apomixis is unevenly distributed across the range of the genus, with the Paleotropics exhibiting the highest frequency, and has evolved numerous times across the Pteris phylogeny, with predominantly East Asian and South Asian clades containing the most apomictic species. CONCLUSIONS Apomixis arises frequently in Pteris, but apomictic species do not appear to diversify. Species that encompass both apomictic and sexual populations have wider ranges than exclusively sexual or apomictic species, which suggests that sexual and apomictic ferns could occupy separate ecological niches.
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Affiliation(s)
- Kathryn T. Picard
- Department of Botany, National Museum of Natural HistorySmithsonian InstitutionWashingtonDC20560USA
| | - Hannah Ranft
- Department of Botany, National Museum of Natural HistorySmithsonian InstitutionWashingtonDC20560USA
- Johns Hopkins UniversityBaltimoreMaryland21218USA
- Department of BiologyUniversity of Minnesota DuluthDuluthMinnesota55812USA
| | - Amanda L. Grusz
- Department of BiologyUniversity of Minnesota DuluthDuluthMinnesota55812USA
| | | | - Eric Schuettpelz
- Department of Botany, National Museum of Natural HistorySmithsonian InstitutionWashingtonDC20560USA
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Dalapicolla J, Alves R, Jaffé R, Vasconcelos S, Pires ES, Nunes GL, Pereira JBDS, Guimarães JTF, Dias MC, Fernandes TN, Scherer D, dos Santos FMG, Castilho A, Santos MP, Calderón EN, Martins RL, da Fonseca RN, Esteves FDA, Caldeira CF, Oliveira G. Conservation implications of genetic structure in the narrowest endemic quillwort from the Eastern Amazon. Ecol Evol 2021; 11:10119-10132. [PMID: 34367563 PMCID: PMC8328431 DOI: 10.1002/ece3.7812] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 06/01/2021] [Indexed: 02/05/2023] Open
Abstract
The quillwort Isoëtes cangae is a critically endangered species occurring in a single lake in Serra dos Carajás, Eastern Amazon. Low genetic diversity and small effective population sizes (N e) are expected for narrow endemic species (NES). Conservation biology studies centered in a single species show some limitations, but they are still useful considering the limited time and resources available for protection of species at risk of extinction. Here, we evaluated the genetic diversity, population structure, N e, and minimum viable population (MVP) of I. cangae to provide information for effective conservation programs. Our analyses were based on 55 individuals collected from the Amendoim Lake and 35,638 neutral SNPs. Our results indicated a single panmictic population, moderate levels of genetic diversity, and N e in the order of thousands, contrasting the expected for NES. Negative FIS values were also found, suggesting that I. cangae is not under risk of inbreeding depression. Our findings imply that I. cangae contains enough genetic diversity to ensure evolutionary potential and that all individuals should be treated as one demographic unit. These results provide essential information to optimize ex situ conservation efforts and genetic diversity monitoring, which are currently applied to guide I. cangae conservation plans.
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Affiliation(s)
| | | | - Rodolfo Jaffé
- Instituto Tecnológico ValeBelémBrazil
- ExponentBellevueWAUSA
| | | | | | | | | | | | - Mariana C. Dias
- Instituto Tecnológico ValeBelémBrazil
- Programa Interunidades de Pós‐Graduação em BioinformáticaUniversidade Federal de Minas GeraisBelo HorizonteBrazil
| | | | - Daniela Scherer
- VALE S/AGerência de Estudos AmbientaisLicenciamento e EspeleologiaNova LimaBrazil
| | | | - Alexandre Castilho
- VALE S/AGerência de Estudos AmbientaisLicenciamento e EspeleologiaNova LimaBrazil
| | - Mirella Pupo Santos
- Instituto de Biodiversidade e Sustentabilidade NUPEMUniversidade Federal do Rio de JaneiroMacaéBrazil
| | - Emiliano Nicolas Calderón
- Instituto de Biodiversidade e Sustentabilidade NUPEMUniversidade Federal do Rio de JaneiroMacaéBrazil
| | - Rodrigo Lemes Martins
- Instituto de Biodiversidade e Sustentabilidade NUPEMUniversidade Federal do Rio de JaneiroMacaéBrazil
| | - Rodrigo Nunes da Fonseca
- Instituto de Biodiversidade e Sustentabilidade NUPEMUniversidade Federal do Rio de JaneiroMacaéBrazil
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Grusz AL, Windham MD, Picard KT, Pryer KM, Schuettpelz E, Haufler CH. A drought-driven model for the evolution of obligate apomixis in ferns: evidence from pellaeids (Pteridaceae). AMERICAN JOURNAL OF BOTANY 2021; 108:263-283. [PMID: 33624306 DOI: 10.1002/ajb2.1611] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 01/20/2021] [Indexed: 06/12/2023]
Abstract
PREMISE Xeric environments impose major constraints on the fern life cycle, yet many lineages overcome these limitations by evolving apomixis. Here, we synthesize studies of apomixis in ferns and present an evidence-based model for the evolution and establishment of this reproductive strategy, focusing on genetic and environmental factors associated with its two defining traits: the production of "unreduced" spores (n = 2n) and the initiation of sporophytes from gametophyte tissue (i.e., diplospory and apogamy, respectively). METHODS We evaluated existing literature in light of the hypothesis that abiotic characteristics of desert environments (e.g., extreme diurnal temperature fluctuations, high light intensity, and water limitation) drive the evolution of obligate apomixis. Pellaeid ferns (Cheilanthoideae: Pteridaceae) were examined in detail, as an illustrative example. We reconstructed a plastid (rbcL, trnG-trnR, atpA) phylogeny for the clade and mapped reproductive mode (sexual versus apomictic) and ploidy across the resulting tree. RESULTS Our six-stage model for the evolution of obligate apomixis in ferns emphasizes the role played by drought and associated abiotic conditions in the establishment of this reproductive approach. Furthermore, our updated phylogeny of pellaeid ferns reveals repeated origins of obligate apomixis and shows an increase in the frequency of apomixis, and rarity of sexual reproduction, among taxa inhabiting increasingly dry North American deserts. CONCLUSIONS Our findings reinforce aspects of other evolutionary, physiological, developmental, and omics-based studies, indicating a strong association between abiotic factors and the establishment of obligate apomixis in ferns. Water limitation, in particular, appears critical to establishment of this reproductive mode.
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Affiliation(s)
- Amanda L Grusz
- Department of Biology, University of Minnesota Duluth, Duluth, MN, 55812, USA
| | | | - Kathryn T Picard
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, D.C., 20013, USA
| | | | - Eric Schuettpelz
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, D.C., 20013, USA
| | - Christopher H Haufler
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, 66045, USA
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