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Swensen SM, Gomez AM, Piasecki-Masters C, Chime N, Wine AR, Rodriguez NC, Conklin J, Melcher PJ. Minimal impacts of invasive Scaevola taccada on Scaevola plumieri via pollinator competition in Puerto Rico. Front Plant Sci 2024; 15:1281797. [PMID: 38332769 PMCID: PMC10850390 DOI: 10.3389/fpls.2024.1281797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 01/04/2024] [Indexed: 02/10/2024]
Abstract
Introduction Scaevola taccada and Scaevola plumieri co-occur on shorelines of the Caribbean. Scaevola taccada is introduced in this habitat and directly competes with native dune vegetation, including S. plumieri, a species listed as locally endangered and threatened in Caribbean locations. This study addresses whether the invasive S. taccada also impacts the native S. plumieri indirectly by competing for pollinators and represents the first comparative study of insect visitation between these species. Methods Insect visitation rates were measured at sites where species co-occur and where only the native occurs. Where species cooccur, insect visitors were captured, identified and analyzed for the pollen they carry. Pollen found on open-pollinated flowers was analyzed to assess pollen movement between the two species. We also compared floral nectar from each species by measuring volume, sugar content, and presence and proportions of amine group containing constituents (AGCCs). Results Our results demonstrate that both species share insect visitors providing the context for possible pollinator competition, yet significant differences in visitation frequency were not found. We found evidence of asymmetrical heterospecific pollen deposition in the native species, suggesting a possible reproductive impact. Insect visitation rates for the native were not significantly different between invaded and uninvaded sites, suggesting that the invasive S. taccada does not limit pollinator visits to S. plumieri. Comparisons of nectar rewards from the invasive and the native reveal similar volumes and sugar concentrations, but significant differences in some amine group containing constituents that may enhance pollinator attraction. Conclusion Our analysis finds no evidence for pollination competition and therefore S. taccada's main impacts on S. plumieri are through competitive displacement and possibly through reproductive impacts as a consequence of heterospecific pollen deposition.
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Affiliation(s)
- Susan M. Swensen
- Department of Biology, Ithaca College, Ithaca, NY, United States
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Affiliation(s)
- Marty A. Condon
- Department of Biology, Cornell College, Mount Vernon, IA 52314, USA
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA
- Systematic Entomology Laboratory, ARS-USDA, Beltsville, MD 20705, USA
- Department of Entomology, University of Maryland, College Park, MD 20742, USA
- Department of Biology, Ithaca College, Ithaca, NY 14850, USA
| | - Sonja J. Scheffer
- Department of Biology, Cornell College, Mount Vernon, IA 52314, USA
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA
- Systematic Entomology Laboratory, ARS-USDA, Beltsville, MD 20705, USA
- Department of Entomology, University of Maryland, College Park, MD 20742, USA
- Department of Biology, Ithaca College, Ithaca, NY 14850, USA
| | - Matthew L. Lewis
- Department of Biology, Cornell College, Mount Vernon, IA 52314, USA
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA
- Systematic Entomology Laboratory, ARS-USDA, Beltsville, MD 20705, USA
- Department of Entomology, University of Maryland, College Park, MD 20742, USA
- Department of Biology, Ithaca College, Ithaca, NY 14850, USA
| | - Susan M. Swensen
- Department of Biology, Cornell College, Mount Vernon, IA 52314, USA
- Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA
- Systematic Entomology Laboratory, ARS-USDA, Beltsville, MD 20705, USA
- Department of Entomology, University of Maryland, College Park, MD 20742, USA
- Department of Biology, Ithaca College, Ithaca, NY 14850, USA
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Berry AM, Murphy TM, Okubara PA, Jacobsen KR, Swensen SM, Pawlowski K. Novel expression pattern of cytosolic Gln synthetase in nitrogen-fixing root nodules of the actinorhizal host, Datisca glomerata. Plant Physiol 2004; 135:1849-62. [PMID: 15247391 PMCID: PMC519095 DOI: 10.1104/pp.103.031534] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2003] [Revised: 04/14/2004] [Accepted: 05/02/2004] [Indexed: 05/24/2023]
Abstract
Gln synthetase (GS) is the key enzyme of primary ammonia assimilation in nitrogen-fixing root nodules of legumes and actinorhizal (Frankia-nodulated) plants. In root nodules of Datisca glomerata (Datiscaceae), transcripts hybridizing to a conserved coding region of the abundant nodule isoform, DgGS1-1, are abundant in uninfected nodule cortical tissue, but expression was not detectable in the infected zone or in the nodule meristem. Similarly, the GS holoprotein is immunolocalized exclusively to the uninfected nodule tissue. Phylogenetic analysis of the full-length cDNA of DgGS1-1 indicates affinities with cytosolic GS genes from legumes, the actinorhizal species Alnus glutinosa, and nonnodulating species, Vitis vinifera and Hevea brasilensis. The D. glomerata nodule GS expression pattern is a new variant among reported root nodule symbioses and may reflect an unusual nitrogen transfer pathway from the Frankia nodule microsymbiont to the plant infected tissue, coupled to a distinctive nitrogen cycle in the uninfected cortical tissue. Arg, Gln, and Glu are the major amino acids present in D. glomerata nodules, but Arg was not detected at high levels in leaves or roots. Arg as a major nodule nitrogen storage form is not found in other root nodule types except in the phylogenetically related Coriaria. Catabolism of Arg through the urea cycle could generate free ammonium in the uninfected tissue where GS is expressed.
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Affiliation(s)
- Alison M Berry
- Department of Environmental Horticulture, University of California, Davis, California 95616, USA.
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Clement WL, Tebbitt MC, Forrest LL, Blair JE, Brouillet L, Eriksson T, Swensen SM. Phylogenetic position and biogeography of Hillebrandia sandwicensis (Begoniaceae): a rare Hawaiian relict. Am J Bot 2004; 91:905-917. [PMID: 21653447 DOI: 10.3732/ajb.91.6.905] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The Begoniaceae consist of two genera, Begonia, with approximately 1400 species that are widely distributed in the tropics, and Hillebrandia, with one species that is endemic to the Hawaiian Islands and the only member of the family native to those islands. To help explain the history of Hillebrandia on the Hawaiian Archipelago, phylogenetic relationships of the Begoniaceae and the Cucurbitales were inferred using sequence data from 18S, rbcL, and ITS, and the minimal age of both Begonia and the Begoniaceae were indirectly estimated. The analyses strongly support the placement of Hillebrandia as the sister group to the rest of the Begoniaceae and indicate that the Hillebrandia lineage is at least 51-65 million years old, an age that predates the current Hawaiian Islands by about 20 million years. Evidence that Hillebrandia sandwicensis has survived on the Hawaiian Archipelago by island hopping from older, now denuded islands to younger, more mountainous islands is presented. Various scenarios for the origin of ancestor to Hillebrandia are considered. The geographic origin of source populations unfortunately remains obscure; however, we suggest a boreotropic or a Malesian-Pacific origin is most likely. Hillebrandia represents the first example in the well-studied Hawaiian flora of a relict genus.
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Affiliation(s)
- Wendy L Clement
- Department of Plant Biology, University of Minnesota, St. Paul, Minnesota 55108 USA
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Soltis DE, Soltis PS, Morgan DR, Swensen SM, Mullin BC, Dowd JM, Martin PG. Chloroplast gene sequence data suggest a single origin of the predisposition for symbiotic nitrogen fixation in angiosperms. Proc Natl Acad Sci U S A 1995; 92:2647-51. [PMID: 7708699 PMCID: PMC42275 DOI: 10.1073/pnas.92.7.2647] [Citation(s) in RCA: 363] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Of the approximately 380 families of angiosperms, representatives of only 10 are known to form symbiotic associations with nitrogen-fixing bacteria in root nodules. The morphologically based classification schemes proposed by taxonomists suggest that many of these 10 families of plants are only distantly related, engendering the hypothesis that the capacity to fix nitrogen evolved independently several, if not many, times. This has in turn influenced attitudes toward the likelihood of transferring genes responsible for symbiotic nitrogen fixation to crop species lacking this ability. Phylogenetic analysis of DNA sequences for the chloroplast gene rbcL indicates, however, that representatives of all 10 families with nitrogen-fixing symbioses occur together, with several families lacking this association, in a single clade. This study therefore indicates that only one lineage of closely related taxa achieved the underlying genetic architecture necessary for symbiotic nitrogen fixation in root nodules.
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Affiliation(s)
- D E Soltis
- Department of Botany, Washington State University, Pullman 99164-4238, USA
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Chase MW, Soltis DE, Olmstead RG, Morgan D, Les DH, Mishler BD, Duvall MR, Price RA, Hills HG, Qiu YL, Kron KA, Rettig JH, Conti E, Palmer JD, Manhart JR, Sytsma KJ, Michaels HJ, Kress WJ, Karol KG, Clark WD, Hedren M, Gaut BS, Jansen RK, Kim KJ, Wimpee CF, Smith JF, Furnier GR, Strauss SH, Xiang QY, Plunkett GM, Soltis PS, Swensen SM, Williams SE, Gadek PA, Quinn CJ, Eguiarte LE, Golenberg E, Learn GH, Graham SW, Barrett SCH, Dayanandan S, Albert VA. Phylogenetics of Seed Plants: An Analysis of Nucleotide Sequences from the Plastid Gene rbcL. Annals of the Missouri Botanical Garden 1993; 80:528. [PMID: 0 DOI: 10.2307/2399846] [Citation(s) in RCA: 632] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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