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Elgorriaga A, Atkinson BA. Cretaceous pollen cone with three-dimensional preservation sheds light on the morphological evolution of cycads in deep time. THE NEW PHYTOLOGIST 2023; 238:1695-1710. [PMID: 36943236 DOI: 10.1111/nph.18852] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
The Cycadales are an ancient and charismatic group of seed plants. However, their morphological evolution in deep time is poorly understood. While molecular divergence time analyses estimate a Cretaceous origin for most major living cycad clades, much of the extant diversity is inferred to be a result of Neogene diversifications. This leads to long branches throughout the cycadalean phylogeny that, with few exceptions, have yet to be rectified by unequivocal fossil cycads. We report a permineralized pollen cone from the Campanian Holz Shale located in Silverado Canyon, CA, USA (c. 80 million yr ago). This fossil was studied via serial sectioning, SEM, 3D reconstruction and phylogenetic analyses. Microsporophyll and pollen morphology indicate this cone is assignable to Skyttegaardia, a recently described genus based on disarticulated lignitized microsporophylls from the Early Cretaceous of Denmark. Data from this new species, including a simple cone architecture, anatomical details and vasculature organization, indicate cycadalean affinities for Skyttegaardia. Phylogenetic analyses support this assignment and recover Skyttegaardia as crown-group Cycadales, nested within Zamiaceae. Our findings support a Cretaceous diversification for crown-group Zamiaceae, which included the evolution of morphological divergent extinct taxa with unique traits that have yet to be widely identified in the fossil record.
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Affiliation(s)
- Andres Elgorriaga
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, 66045, USA
- Biodiversity Institute, University of Kansas, Lawrence, KS, 66045, USA
| | - Brian A Atkinson
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, 66045, USA
- Biodiversity Institute, University of Kansas, Lawrence, KS, 66045, USA
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2
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Salzman S, Crook D, Calonje M, Stevenson DW, Pierce NE, Hopkins R. Cycad-Weevil Pollination Symbiosis Is Characterized by Rapidly Evolving and Highly Specific Plant-Insect Chemical Communication. FRONTIERS IN PLANT SCIENCE 2021; 12:639368. [PMID: 33995438 PMCID: PMC8121082 DOI: 10.3389/fpls.2021.639368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 04/12/2021] [Indexed: 06/12/2023]
Abstract
Coevolution between plants and insects is thought to be responsible for generating biodiversity. Extensive research has focused largely on antagonistic herbivorous relationships, but mutualistic pollination systems also likely contribute to diversification. Here we describe an example of chemically-mediated mutualistic species interactions affecting trait evolution and lineage diversification. We show that volatile compounds produced by closely related species of Zamia cycads are more strikingly different from each other than are other phenotypic characters, and that two distantly related pollinating weevil species have specialized responses only to volatiles from their specific host Zamia species. Plant transcriptomes show that approximately a fifth of genes related to volatile production are evolving under positive selection, but we find no differences in the relative proportion of genes under positive selection in different categories. The importance of phenotypic divergence coupled with chemical communication for the maintenance of this obligate mutualism highlights chemical signaling as a key mechanism of coevolution between cycads and their weevil pollinators.
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Affiliation(s)
- Shayla Salzman
- Plant Sciences, Cornell University, Ithaca, NY, United States
- Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, United States
| | - Damon Crook
- Otis Laboratory, USDA-APHIS-PPQ CPHST, Otis ANGB, MA, United States
| | - Michael Calonje
- Montgomery Botanical Center, Coral Gables, FL, United States
| | | | - Naomi E. Pierce
- Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, United States
| | - Robin Hopkins
- Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, United States
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3
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Gutiérrez-Ortega JS, Salinas-Rodríguez MM, Ito T, Pérez-Farrera MA, Vovides AP, Martínez JF, Molina-Freaner F, Hernández-López A, Kawaguchi L, Nagano AJ, Kajita T, Watano Y, Tsuchimatsu T, Takahashi Y, Murakami M. Niche conservatism promotes speciation in cycads: the case of Dioon merolae (Zamiaceae) in Mexico. THE NEW PHYTOLOGIST 2020; 227:1872-1884. [PMID: 32392621 DOI: 10.1111/nph.16647] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 04/22/2020] [Indexed: 06/11/2023]
Abstract
Niche conservatism is the tendency of lineages to retain the same niche as their ancestors. It constrains biological groups and prevents ecological divergence. However, theory predicts that niche conservatism can hinder gene flow, strengthen drift and increase local adaptation: does it mean that it also can facilitate speciation? Why does this happen? We aim to answer these questions. We examined the variation of chloroplast DNA, genome-wide single nucleotide polymorphisms, morphological traits and environmental variables across the Dioon merolae cycad populations. We tested geographical structure, scenarios of demographic history, and niche conservatism between population groups. Lineage divergence is associated with the presence of a geographical barrier consisting of unsuitable habitats for cycads. There is a clear genetic and morphological distinction between the geographical groups, suggesting allopatric divergence. However, even in contrasting available environmental conditions, groups retain their ancestral niche, supporting niche conservatism. Niche conservatism is a process that can promote speciation. In D. merolae, lineage divergence occurred because unsuitable habitats represented a barrier against gene flow, incurring populations to experience isolated demographic histories and disparate environmental conditions. This study explains why cycads, despite their ancient lineage origin and biological stasis, have been able to diversify into modern ecosystems worldwide.
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Affiliation(s)
| | | | - Takuro Ito
- Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan
| | - Miguel Angel Pérez-Farrera
- Laboratorio de Ecología Evolutiva, Herbario Eizi Matuda, Instituto de Ciencias Biológicas, Universidad de Ciencias y Artes de Chiapas, Tuxtla Gutiérrez, 29039, Mexico
| | - Andrew P Vovides
- Departamento de Biología Evolutiva, Instituto de Ecología, A.C., Xalapa, 91070, Mexico
| | - José F Martínez
- Departamento de Ecología de la Biodiversidad, Instituto de Ecología, Universidad Nacional Autónoma de México, Hermosillo, 83250, Mexico
| | - Francisco Molina-Freaner
- Departamento de Ecología de la Biodiversidad, Instituto de Ecología, Universidad Nacional Autónoma de México, Hermosillo, 83250, Mexico
| | - Antonio Hernández-López
- Ciencias Agrogenómicas, Escuela Nacional de Estudios Superiores, Universidad Nacional Autónoma de México, León, 37684, Mexico
| | - Lina Kawaguchi
- Faculty of Agriculture, Ryukoku University, Otsu, Shiga, 520-2194, Japan
| | - Atsushi J Nagano
- Faculty of Agriculture, Ryukoku University, Otsu, Shiga, 520-2194, Japan
| | - Tadashi Kajita
- Iriomote Station, Tropical Biosphere Research Center, University of the Ryukyus, Uehara, Yaeyama, Okinawa, 907-1541, Japan
| | - Yasuyuki Watano
- Department of Biology, Faculty of Science, Chiba University, Chiba, 263-8522, Japan
| | - Takashi Tsuchimatsu
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Yuma Takahashi
- Department of Biology, Faculty of Science, Chiba University, Chiba, 263-8522, Japan
| | - Masashi Murakami
- Department of Biology, Faculty of Science, Chiba University, Chiba, 263-8522, Japan
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4
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Affiliation(s)
- Alicia Toon
- School of Biological Sciences; The University of Queensland; Brisbane Queensland 4072 Australia
| | - L. Irene Terry
- School of Biological Sciences; University of Utah; Salt Lake City Utah USA
| | | | - Gimme H. Walter
- School of Biological Sciences; The University of Queensland; Brisbane Queensland 4072 Australia
| | - Lyn G. Cook
- School of Biological Sciences; The University of Queensland; Brisbane Queensland 4072 Australia
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Salzman S, Crook D, Crall JD, Hopkins R, Pierce NE. An ancient push-pull pollination mechanism in cycads. SCIENCE ADVANCES 2020; 6:eaay6169. [PMID: 32582845 PMCID: PMC7292639 DOI: 10.1126/sciadv.aay6169] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 04/17/2020] [Indexed: 05/25/2023]
Abstract
Most cycads engage in brood-site pollination mutualisms, yet the mechanism by which the Cycadales entice pollination services from diverse insect mutualists remains unknown. Here, we characterize a push-pull pollination mechanism between a New World cycad and its weevil pollinators that mirrors the mechanism between a distantly related Old World cycad and its thrips pollinators. The behavioral convergence between weevils and thrips, combined with molecular phylogenetic dating and a meta-analysis of thermogenesis and coordinated patterns of volatile attraction and repulsion suggest that a push-pull pollination mutualism strategy is ancestral in this ancient, dioecious plant group. Hence, it may represent one of the earliest insect/plant pollination mechanisms, arising long before the evolution of visual floral signaling commonly used by flowering plants.
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Affiliation(s)
- Shayla Salzman
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
- The Arnold Arboretum, Harvard University, Boston, MA 02131, USA
- Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
| | - Damon Crook
- USDA-APHIS-PPQ CPHST, Otis Laboratory, Building 1398, Otis ANGB, MA 02542, USA
| | - James D. Crall
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
| | - Robin Hopkins
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
- The Arnold Arboretum, Harvard University, Boston, MA 02131, USA
| | - Naomi E. Pierce
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
- Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
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Hernández-Hernández T, Wiens JJ. Why Are There So Many Flowering Plants? A Multiscale Analysis of Plant Diversification. Am Nat 2020; 195:948-963. [DOI: 10.1086/708273] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Wang XH, Li J, Zhang LM, He ZW, Mei QM, Gong X, Jian SG. Population Differentiation and Demographic History of the Cycas taiwaniana Complex (Cycadaceae) Endemic to South China as Indicated by DNA Sequences and Microsatellite Markers. Front Genet 2019; 10:1238. [PMID: 31921292 PMCID: PMC6935862 DOI: 10.3389/fgene.2019.01238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 11/08/2019] [Indexed: 11/13/2022] Open
Abstract
Historical geology, climatic oscillations, and seed dispersal capabilities are thought to influence the population dynamics and genetics of plants, especially for distribution-restricted and threatened species. Investigating the genetic resources within and among taxa is a prerequisite for conservation management. The Cycas taiwaniana complex consists of six endangered species that are endemic to South China. In this study, we investigated the relationship between phylogeographic history and the genetic structure of the C. taiwaniana complex. To estimate the phylogeographic history of the complex, we assessed the genetic structure and divergence time, and performed phylogenetic and demographic historical analyses. Two chloroplast DNA intergenic regions (cpDNA), two single-copy nuclear genes (SCNGs), and six microsatellite loci (SSR) were sequenced for 18 populations. The SCNG data indicated a high genetic diversity within populations, a low genetic diversity among populations, and significant genetic differentiation among populations. Significant phylogeographical structure was detected. Structure and phylogenetic analyses both revealed that the 18 populations of the C. taiwaniana complex have two main lineages, which were estimated to diverge in the Middle Pleistocene. We propose that Cycas fairylakea was incorporated into Cycas szechuanensis and that the other populations, which are mainly located on Hainan Island, merged into one lineage. Bayesian skyline plot analyses revealed that the C. taiwaniana complex experienced a recent decline, suggesting that the complex probably experienced a bottleneck event. We infer that the genetic structure of the C. taiwaniana complex has been affected by Pleistocene climate shifts, sea-level oscillations, and human activities. In addition to providing new insights into the evolutionary legacy of the genus, the genetic characterizations will be useful for the conservation of Cycas species.
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Affiliation(s)
- Xin-Hui Wang
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Jie Li
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Li-Min Zhang
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Zi-Wen He
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Qi-Ming Mei
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Xun Gong
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Shu-Guang Jian
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
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Chłond D, Sawka-Gądek N, Żyła D. Genetic data of museum specimens allow for inferring evolutionary history of the cosmopolitan genus Sirthenea (Heteroptera: Reduviidae). PeerJ 2019; 7:e6640. [PMID: 30993035 PMCID: PMC6462186 DOI: 10.7717/peerj.6640] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 02/18/2019] [Indexed: 11/20/2022] Open
Abstract
Among the 30 known genera within subfamily Peiratinae, only the genus Sirthenea has a cosmopolitan distribution. The results of our studies are the first comprehensive analysis concerning one of the representatives of mentioned subfamily based on joint phylogenetic analyses of molecular and morphological data as well as molecular dating. A total of 32 species were included into the dataset with all known species of the genus Sirthenea. Material of over 400 dry specimens was examined for the morphological part of this study. The cosmopolitan distribution of Sirthenea and the inaccessibility of specimens preserved in alcohol required the extraction of DNA from the dried skeletal muscles of specimens deposited in 24 entomological collections. The oldest specimens used for the successful extraction and sequencing were collected more than 120 years ago in India. We performed Bayesian Inference analyses of molecular and morphological data separately, as well as combined analysis. The molecular and morphological data obtained during our research verify the correlation of the divergence dates of all known Sirthenea species. Results of the relaxed molecular clock analysis of the molecular data show that, the genus Sirthenea started diverging in the Late Cretaceous into two clades, which subsequently began to branch off in the Paleocene. Our results of phylogenetic analyses suggest that the fossula spongiosa and its development could be one of the most important morphological characters in the evolution of the genus, most likely associated with the ecological niche inhabited by Sirthenea representatives. Confirmation of the results obtained in our studies is the reconciliation of the evolutionary history of Sirthenea with the biogeographical processes that have shaped current global distribution of the genus.
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Affiliation(s)
- Dominik Chłond
- Faculty of Biology and Environmental Protection, Department of Zoology, University of Silesia, Katowice, Poland
| | - Natalia Sawka-Gądek
- Institute of Systematic and Evolution of Animals, Polish Academy of Science, Kraków, Poland
| | - Dagmara Żyła
- Department of Ecology, Evolution, & Organismal Biology, Iowa State University, Ames, IA, USA
- Department of Invertebrate Zoology and Parasitology, University of Gdańsk, Gdańsk, Poland
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