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Meng Y, Geng X, Zhu P, Bai X, Zhang P, Ni G, Hou Y. Enhanced mutualism: A promotional effect driven by bacteria during the early invasion of Phytolacca americana. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2024; 34:e2742. [PMID: 36107405 DOI: 10.1002/eap.2742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 07/19/2022] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
The enhanced mutualism hypothesis postulates that invasive plants promote self-growth by enriching beneficial microbes to establish a positive soil feedback. However, the roles of soil microorganisms may vary with increasing time for plant growth. Research on changes in soil microbial communities over time has important implications for understanding the mechanisms underlying plant invasion. Due to the difficulty in evaluating the duration of plant growth, few studies have quantified the changes in soil microorganisms with increasing plant age. This study focuses on the invasive weed Phytolacca americana L., which has growth rings in the main root. We conducted a two-stage experiment in the field and greenhouse to explore the soil feedback changes with duration of plant growth. We determined the effects of P. americana at different ages on the soil microbial community and soil properties and performed a soil inoculation experiment to quantify the influence of soil microbes on seed germination and seedling performance. We found that the content of some soil nutrients, namely total nitrogen, total phosphorus, nitrate-N, and available phosphorus, significantly decreased with increasing growth age of P. americana, whereas the available potassium showed an opposite increasing trend. The P. americana growth age also significantly influenced the soil bacterial community structure. However, this phenomenon did not occur in the fungal community. In the bacterial community, the relative abundance of plant growth-promoting bacteria showed an increasing trend. The soil inoculation experiment had high seed germination rates and biomass accumulation when the plants were grown in conditioned soil from P. americana growth within 5 years, suggesting a positive plant-soil feedback. However, the promoting effect disappeared in conditioned soil from 10 years of age. Our findings demonstrate that plant growth-promoting bacteria significantly accumulated in the soil during the early stages of P. americana invasion, and that the strength of enhanced positive feedback may play a crucial role in facilitating P. americana invasion. This study highlights the changing nature of plant-microbe interactions during biological invasion and illustrates how bacteria could contribute to the initial success of P. americana, providing new insights into the underlying mechanisms of plant invasion.
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Affiliation(s)
- Yunhao Meng
- College of Life Sciences, Ludong University, Yantai, China
| | - Xinze Geng
- College of Life Sciences, Ludong University, Yantai, China
| | - Ping Zhu
- College of Life Sciences, Ludong University, Yantai, China
| | - Xinfu Bai
- College of Life Sciences, Ludong University, Yantai, China
| | - Ping Zhang
- College of Life Sciences, Ludong University, Yantai, China
| | - Guangyan Ni
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Yuping Hou
- College of Life Sciences, Ludong University, Yantai, China
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2
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Nathan P, Economo EP, Guénard B, Simonsen AK, Frederickson ME. Generalized mutualisms promote range expansion in both plant and ant partners. Proc Biol Sci 2023; 290:20231083. [PMID: 37700642 PMCID: PMC10498038 DOI: 10.1098/rspb.2023.1083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 08/14/2023] [Indexed: 09/14/2023] Open
Abstract
Mutualism improves organismal fitness, but strong dependence on another species can also limit a species' ability to thrive in a new range if its partner is absent. We assembled a large, global dataset on mutualistic traits and species ranges to investigate how multiple plant-animal and plant-microbe mutualisms affect the spread of legumes and ants to novel ranges. We found that generalized mutualisms increase the likelihood that a species establishes and thrives beyond its native range, whereas specialized mutualisms either do not affect or reduce non-native spread. This pattern held in both legumes and ants, indicating that specificity between mutualistic partners is a key determinant of ecological success in a new habitat. Our global analysis shows that mutualism plays an important, if often overlooked, role in plant and insect invasions.
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Affiliation(s)
- Pooja Nathan
- Department of Ecology & Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto M5S 3B2, Ontario, Canada
| | - Evan P. Economo
- Biodiversity and Biocomplexity Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan
| | - Benoit Guénard
- School of Biological Sciences, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Anna K. Simonsen
- Department of Biological Sciences, Florida International University, 11200 SW 8th St, Miami, FL 33199, USA
| | - Megan E. Frederickson
- Department of Ecology & Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto M5S 3B2, Ontario, Canada
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Jesus JG, Máguas C, Dias R, Nunes M, Pascoal P, Pereira M, Trindade H. What If Root Nodules Are a Guesthouse for a Microbiome? The Case Study of Acacia longifolia. BIOLOGY 2023; 12:1168. [PMID: 37759568 PMCID: PMC10525506 DOI: 10.3390/biology12091168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/20/2023] [Accepted: 08/23/2023] [Indexed: 09/29/2023]
Abstract
Acacia longifolia is one of the most aggressive invaders worldwide whose invasion is potentiated after a fire, a common perturbation in Mediterranean climates. As a legume, this species establishes symbioses with nitrogen-fixing bacteria inside root nodules; however, the overall microbial diversity is still unclear. In this study, we addressed root nodules' structure and biodiversity through histology and Next-Generation Sequencing, targeting 16S and 25S-28S rDNA genes for bacteria and fungi, respectively. We wanted to evaluate the effect of fire in root nodules from 1-year-old saplings, by comparing unburnt and burnt sites. We found that although having the same general structure, after a fire event, nodules had a higher number of infected cells and greater starch accumulation. Starch accumulated in uninfected cells can be a possible carbon source for the microbiota. Regarding diversity, Bradyrhizobium was dominant in both sites (ca. 77%), suggesting it is the preferential partner, followed by Tardiphaga (ca. 9%), a non-rhizobial Alphaproteobacteria, and Synechococcus, a cyanobacteria (ca. 5%). However, at the burnt site, additional N-fixing bacteria were included in the top 10 genera, highlighting the importance of this process. Major differences were found in the mycobiome, which was diverse in both sites and included genera mostly described as plant endophytes. Coniochaeta was dominant in nodules from the burnt site (69%), suggesting its role as a facilitator of symbiotic associations. We highlight the presence of a large bacterial and fungal community in nodules, suggesting nodulation is not restricted to nitrogen fixation. Thus, this microbiome can be involved in facilitating A. longifolia invasive success.
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Affiliation(s)
- Joana G. Jesus
- Centre for Ecology, Evolution and Environmental Change (cE3c), Faculty of Sciences, University of Lisbon (FCUL), Global Change and Sustainability Institute (CHANGE), 1749-016 Lisboa, Portugal; (J.G.J.); (C.M.); (R.D.)
| | - Cristina Máguas
- Centre for Ecology, Evolution and Environmental Change (cE3c), Faculty of Sciences, University of Lisbon (FCUL), Global Change and Sustainability Institute (CHANGE), 1749-016 Lisboa, Portugal; (J.G.J.); (C.M.); (R.D.)
| | - Ricardo Dias
- Centre for Ecology, Evolution and Environmental Change (cE3c), Faculty of Sciences, University of Lisbon (FCUL), Global Change and Sustainability Institute (CHANGE), 1749-016 Lisboa, Portugal; (J.G.J.); (C.M.); (R.D.)
- Biosystems and Integrative Sciences Institute (BioISI), 1749-016 Lisboa, Portugal
| | - Mónica Nunes
- Centro de Testes de Ciências, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal; (M.N.); (P.P.); (M.P.)
| | - Pedro Pascoal
- Centro de Testes de Ciências, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal; (M.N.); (P.P.); (M.P.)
| | - Marcelo Pereira
- Centro de Testes de Ciências, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal; (M.N.); (P.P.); (M.P.)
| | - Helena Trindade
- Centre for Ecology, Evolution and Environmental Change (cE3c), Faculty of Sciences, University of Lisbon (FCUL), Global Change and Sustainability Institute (CHANGE), 1749-016 Lisboa, Portugal; (J.G.J.); (C.M.); (R.D.)
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Warrington S, Ellis AG, Keet JH, Le Roux JJ. How does familiarity in rhizobial interactions impact the performance of invasive and native legumes? NEOBIOTA 2022. [DOI: 10.3897/neobiota.72.79620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mutualisms can be disrupted when non-native plants are introduced into novel environments, potentially impacting their establishment success. Introduced species can reassemble mutualisms by forming novel associations with resident biota or by maintaining familiar associations when they are co-introduced with their mutualists. Invasive Australian Acacia species in South Africa have formed nitrogen-fixing rhizobium mutualisms using both pathways.
Here we examined the contributions of novel vs familiar rhizobial associations to the performance of Acacia saligna across different soils within South Africa’s Core Cape Subregion (CCR), and the concomitant impacts of exotic rhizobia on the endemic legume, Psoralea pinnata. We grew each legume with and without Australian Bradyrhizobium strains across various CCR soil types in a glasshouse. We identified root nodule rhizobium communities associating with seedlings grown in each treatment combination using next-generation sequencing (NGS) techniques.
Our results show that different CCR soils affected growth performances of seedlings for both species while the addition of Australian bradyrhizobia affected growth performances of A. saligna, but not P. pinnata. NGS data revealed that each legume associated mostly with their familiar rhizobial partners, regardless of soil conditions or inoculum treatment. Acacia saligna predominantly associated with Australian bradyrhizobia, even when grown in soils without inoculum, while P. pinnata largely associated with native South African Mesorhizobium strains.
Our study suggests that exotic Australian bradyrhizobia are already present and widespread in pristine CCR soils, and that mutualist limitation is not an impediment to further acacia invasion in the region. The ability of P. pinnata to sanction Australian Bradyrhizobium strains suggests that this species may be a good candidate for restoration efforts following the removal of acacias in CCR habitats.
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Wandrag EM, Birnbaum C, Klock MM, Barrett LG, Thrall PH. Availability of soil mutualists may not limit non‐native
Acacia
invasion but could increase their impact on native soil communities. J Appl Ecol 2020. [DOI: 10.1111/1365-2664.13577] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Elizabeth M. Wandrag
- School of Environmental and Rural Science University of New England Armidale NSW Australia
- Institute for Applied Ecology University of Canberra Canberra ACT Australia
| | | | - Metha M. Klock
- Department of Environmental Studies San José State University San José CA USA
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Manea A, Tabassum S, Carthey AJR, Cameron DNS, Leishman MR. Evidence for a shift in defence driving the invasion success of Acacia longifolia in Australia. Biol Invasions 2019. [DOI: 10.1007/s10530-019-01968-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Using Network Theory to Understand and Predict Biological Invasions. Trends Ecol Evol 2019; 34:831-843. [PMID: 31155422 DOI: 10.1016/j.tree.2019.04.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 04/19/2019] [Accepted: 04/23/2019] [Indexed: 10/26/2022]
Abstract
Understanding and predicting biological invasions is challenging because of the complexity of many interacting players. A holistic approach is needed with the potential to simultaneously consider all relevant effects and effectors. Using networks to describe the relevant anthropogenic and ecological factors, from community-level to global scales, promises advances in understanding aspects of invasion from propagule pressure, through establishment, spread, and ecological impact of invaders. These insights could lead to development of new tools for prevention and management of invasions that are based on species' network characteristics and use of networks to predict the ecological effects of invaders. Here, we review the findings from network ecology that show the most promise for invasion biology and identify pressing needs for future research.
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Bueno A, Greenfield L, Pritsch K, Schmidt S, Simon J. Responses to competition for nitrogen between subtropical native tree seedlings and exotic grasses are species-specific and mediated by soil N availability. TREE PHYSIOLOGY 2019; 39:404-416. [PMID: 30184191 DOI: 10.1093/treephys/tpy096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/25/2018] [Accepted: 08/08/2018] [Indexed: 06/08/2023]
Abstract
Competitive interactions between native tree seedlings and exotic grasses frequently hinder forest restoration. We investigated the consequences of competition with exotic grasses on the growth and net nitrogen (N) uptake capacity of native rainforest seedlings used for reforestation depending on soil N availability and N source. Tree seedlings and grasses were grown in the greenhouse in different competition regimes (one tree species vs one grass species) and controls (grass monocultures or single tree seedlings) at low and high soil N. After 8 weeks, we quantified net N uptake capacity using 15N-labelled organic (i.e., glutamine and arginine) and inorganic (i.e., ammonium and nitrate) N sources and biomass indices. Depending on soil N availability, we observed different species-specific responses to growth and N acquisition. Tree seedlings generally increased their net N uptake capacity in response to competition with grasses, although overall seedling growth was unaffected. In contrast, the responses to competition by the grasses were species-specific and varied with soil N availability. The different N acquisition strategies suggest the avoidance of competition for N between trees and grasses. Overall, the results highlight that quantifying underlying mechanisms of N acquisition complements the information on biomass allocation as a measure of responses to competition, particularly with varying environmental conditions.
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Affiliation(s)
- Andrea Bueno
- Plant Interactions Ecophysiology Group, Department of Biology, University of Konstanz, Universitätsstrasse 10, Konstanz, Germany
| | - Lucy Greenfield
- Plant Nutrition and Ecophysiology Group, School of Agriculture and Food Science, The University of Queensland, St Lucia Qld, Australia
- School of Earth and Environment, The University of Leeds, Leeds, UK
| | - Karin Pritsch
- Institute of Biochemical Plant Pathology, HelmholtzZentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt GmbH, Ingolstaedter Landstrasse 1, 85764 Oberschleiβheim, Germany
| | - Susanne Schmidt
- Plant Nutrition and Ecophysiology Group, School of Agriculture and Food Science, The University of Queensland, St Lucia Qld, Australia
| | - Judy Simon
- Plant Interactions Ecophysiology Group, Department of Biology, University of Konstanz, Universitätsstrasse 10, Konstanz, Germany
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9
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Exploring vascular flora diversity of two protected sandy coastal areas in southern Italy. RENDICONTI LINCEI. SCIENZE FISICHE E NATURALI 2019. [DOI: 10.1007/s12210-019-00789-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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10
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Le Roux JJ, Hui C, Keet JH, Ellis AG. Co-introduction vs ecological fitting as pathways to the establishment of effective mutualisms during biological invasions. THE NEW PHYTOLOGIST 2017; 215:1354-1360. [PMID: 28771816 DOI: 10.1111/nph.14593] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/24/2017] [Indexed: 06/07/2023]
Abstract
Contents 1354 I. 1354 II. 1355 III. 1357 IV. 1357 V. 1359 1359 References 1359 SUMMARY: Interactions between non-native plants and their mutualists are often disrupted upon introduction to new environments. Using legume-rhizobium mutualistic interactions as an example, we discuss two pathways that can influence symbiotic associations in such situations: co-introduction of coevolved rhizobia; and utilization of, and adaptation to, resident rhizobia, hereafter referred to as 'ecological fitting'. Co-introduction and ecological fitting have distinct implications for successful legume invasions and their impacts. Under ecological fitting, initial impacts may be less severe and will accrue over longer periods as novel symbiotic associations and/or adaptations may require fine-tuning over time. Co-introduction will have more profound impacts that will accrue more rapidly as a result of positive feedbacks between densities of non-native rhizobia and their coevolved host plants, in turn enhancing competition between native and non-native rhizobia. Co-introduction can further impact invasion outcomes by the exchange of genetic material between native and non-native rhizobia, potentially resulting in decreased fitness of native legumes. A better understanding of the roles of these two pathways in the invasion dynamics of non-native legumes is much needed, and we highlight some of the exciting research avenues it presents.
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Affiliation(s)
- Johannes J Le Roux
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Matieland, 7602, South Africa
- Department of Botany and Zoology, Stellenbosch University, Matieland, 7602, South Africa
| | - Cang Hui
- Centre for Invasion Biology, Department of Mathematical Sciences, Stellenbosch University, Matieland, 7602, South Africa
- Mathematical and Physical Biosciences, African Institute for Mathematical Sciences, Cape Town, 7945, South Africa
| | - Jan-Hendrik Keet
- Department of Botany and Zoology, Stellenbosch University, Matieland, 7602, South Africa
| | - Allan G Ellis
- Department of Botany and Zoology, Stellenbosch University, Matieland, 7602, South Africa
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Keet JH, Ellis AG, Hui C, Le Roux JJ. Legume-rhizobium symbiotic promiscuity and effectiveness do not affect plant invasiveness. ANNALS OF BOTANY 2017; 119:1319-1331. [PMID: 28369229 PMCID: PMC5604570 DOI: 10.1093/aob/mcx028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Accepted: 02/22/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND AND AIMS The ability to fix atmospheric nitrogen is thought to play an important role in the invasion success of legumes. Interactions between legumes and nitrogen-fixing bacteria (rhizobia) span a continuum of specialization, and promiscuous legumes are thought to have higher chances of forming effective symbioses in novel ranges. Using Australian Acacia species in South Africa, it was hypothesized that widespread and highly invasive species will be more generalist in their rhizobial symbiotic requirements and more effective in fixing atmospheric nitrogen compared with localized and less invasive species. METHODS To test these hypotheses, eight localized and 11 widespread acacias were examined using next-generation sequencing data for the nodulation gene, nodC , to compare the identity, species richness, diversity and compositional similarity of rhizobia associated with these acacias. Stable isotope analysis was also used to determine levels of nitrogen obtained from the atmosphere via symbiotic nitrogen fixation. KEY RESULTS No differences were found in richness, diversity and community composition between localized and widespread acacias. Similarly, widespread and localized acacias did not differ in their ability to fix atmospheric nitrogen. However, for some species by site comparisons, significant differences in δ15N isotopic signatures were found, indicating differential symbiotic effectiveness between these species at specific localities. CONCLUSIONS Overall, the results support recent findings that root nodule rhizobial diversity and community composition do not differ between acacias that vary in their invasiveness. Differential invasiveness of acacias in South Africa is probably linked to attributes such as differences in propagule pressure, reasons for (e.g. forestry vs. ornamental) and extent of, plantings in the country.
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Affiliation(s)
- Jan-Hendrik Keet
- Department of Botany and Zoology, Stellenbosch University, Matieland 7602, South Africa
| | - Allan G. Ellis
- Department of Botany and Zoology, Stellenbosch University, Matieland 7602, South Africa
| | - Cang Hui
- Centre for Invasion Biology, Department of Mathematical Sciences, Stellenbosch University, Matieland 7602, South Africa
- Mathematical and Physical Biosciences, African Institute for Mathematical Sciences, Cape Town 7945, South Africa
| | - Johannes J. Le Roux
- Department of Botany and Zoology, Stellenbosch University, Matieland 7602, South Africa
- Centre for Invasion Biology, Department of Mathematical Sciences, Stellenbosch University, Matieland 7602, South Africa
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Simonsen AK, Dinnage R, Barrett LG, Prober SM, Thrall PH. Symbiosis limits establishment of legumes outside their native range at a global scale. Nat Commun 2017; 8:14790. [PMID: 28387250 PMCID: PMC5385628 DOI: 10.1038/ncomms14790] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 01/30/2017] [Indexed: 12/20/2022] Open
Abstract
Microbial symbiosis is integral to plant growth and reproduction, but its contribution to global patterns of plant distribution is unknown. Legumes (Fabaceae) are a diverse and widely distributed plant family largely dependent on symbiosis with nitrogen-fixing rhizobia, which are acquired from soil after germination. This dependency is predicted to limit establishment in new geographic areas, owing to a disruption of compatible host-symbiont associations. Here we compare non-native establishment patterns of symbiotic and non-symbiotic legumes across over 3,500 species, covering multiple independent gains and losses of rhizobial symbiosis. We find that symbiotic legume species have spread to fewer non-native regions compared to non-symbiotic legumes, providing strong support for the hypothesis that lack of suitable symbionts or environmental conditions required for effective nitrogen-fixation are driving these global introduction patterns. These results highlight the importance of mutualisms in predicting non-native species establishment and the potential impacts of microbial biogeography on global plant distributions.
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Affiliation(s)
- Anna K Simonsen
- Commonwealth Scientific and Industrial Research Organization (CSIRO), Land &Water, Clunies Ross Street, Acton, Australian Capital Territory 2601, Australia
| | - Russell Dinnage
- Research School of Biology, The Australian National University, 116 Daley Road, Acton, Australian Capital Territory 2601, Australia
| | - Luke G Barrett
- CSIRO Agriculture and Food, Canberra, Clunies Ross Street, Acton, Australian Capital Territory 2601, Australia
| | | | - Peter H Thrall
- CSIRO Agriculture and Food, Canberra, Clunies Ross Street, Acton, Australian Capital Territory 2601, Australia
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Klock MM, Barrett LG, Thrall PH, Harms KE. Differential plant invasiveness is not always driven by host promiscuity with bacterial symbionts. AOB PLANTS 2016; 8:plw060. [PMID: 27535176 PMCID: PMC5018393 DOI: 10.1093/aobpla/plw060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 08/08/2016] [Indexed: 05/31/2023]
Abstract
Identification of mechanisms that allow some species to outcompete others is a fundamental goal in ecology and invasive species management. One useful approach is to examine congeners varying in invasiveness in a comparative framework across native and invaded ranges. Acacia species have been widely introduced outside their native range of Australia, and a subset of these species have become invasive in multiple parts of the world. Within specific regions, the invasive status of these species varies. Our study examined whether a key mechanism in the life history of Acacia species, the legume-rhizobia symbiosis, influences acacia invasiveness on a regional scale. To assess the extent to which species varying in invasiveness correspondingly differ with regard to the diversity of rhizobia they associate with, we grew seven Acacia species ranging in invasiveness in California in multiple soils from both their native (Australia) and introduced (California) ranges. In particular, the aim was to determine whether more invasive species formed symbioses with a wider diversity of rhizobial strains (i.e. are more promiscuous hosts). We measured and compared plant performance, including aboveground biomass, survival, and nodulation response, as well as rhizobial community composition and richness. Host promiscuity did not differ among invasiveness categories. Acacia species that varied in invasiveness differed in aboveground biomass for only one soil and did not differ in survival or nodulation within individual soils. In addition, acacias did not differ in rhizobial richness among invasiveness categories. However, nodulation differed between regions and was generally higher in the native than introduced range. Our results suggest that all Acacia species introduced to California are promiscuous hosts and that host promiscuity per se does not explain the observed differences in invasiveness within this region. Our study also highlights the utility of assessing potential mechanisms of invasion in species' native and introduced ranges.
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Affiliation(s)
- Metha M Klock
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Luke G Barrett
- CSIRO Agriculture Flagship, Canberra, ACT 2601, Australia
| | - Peter H Thrall
- CSIRO Agriculture Flagship, Canberra, ACT 2601, Australia
| | - Kyle E Harms
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
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15
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Le Roux JJ, Mavengere NR, Ellis AG. The structure of legume-rhizobium interaction networks and their response to tree invasions. AOB PLANTS 2016; 8:plw038. [PMID: 27255514 PMCID: PMC4940501 DOI: 10.1093/aobpla/plw038] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 05/07/2016] [Indexed: 05/09/2023]
Abstract
Establishing mutualistic interactions in novel environments is important for the successful establishment of some non-native plant species. These associations may, in turn, impact native species interaction networks as non-natives become dominant in their new environments. Using phylogenetic and ecological interaction network approaches we provide the first report of the structure of belowground legume-rhizobium interaction networks and how they change along a gradient of invasion (uninvaded, semi invaded and heavily invaded sites) by Australian Acacia species in South Africa's Cape Floristic Region. We found that native and invasive legumes interact with distinct rhizobial lineages, most likely due to phylogenetic uniqueness of native and invasive host plants. Moreover, legume-rhizobium interaction networks are not nested, but significantly modular with high levels of specialization possibly as a result of legume-rhizobium co-evolution. Although network topology remained constant across the invasion gradient, composition of bacterial communities associated with native legumes changed dramatically as acacias increasingly dominated the landscape. In stark contrast to aboveground interaction networks (e.g. pollination and seed dispersal) we show that invasive legumes do not infiltrate existing native legume-rhizobium networks but rather form novel modules. This absence of mutualist overlap between native and invasive legumes suggests the importance of co-invading rhizobium-acacia species complexes for Acacia invasion success, and argues against a ubiquitous role for the formation and evolutionary refinement of novel interactions.
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Affiliation(s)
- Johannes J Le Roux
- Department of Botany and Zoology, Centre for Invasion Biology, Stellenbosch University, Matieland, 7602, South Africa
| | - Natasha R Mavengere
- Department of Botany and Zoology, Centre for Invasion Biology, Stellenbosch University, Matieland, 7602, South Africa
| | - Allan G Ellis
- Department of Botany and Zoology, Centre for Invasion Biology, Stellenbosch University, Matieland, 7602, South Africa
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Klock MM, Barrett LG, Thrall PH, Harms KE. Host promiscuity in symbiont associations can influence exotic legume establishment and colonization of novel ranges. DIVERS DISTRIB 2015. [DOI: 10.1111/ddi.12363] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Affiliation(s)
- Metha M. Klock
- Department of Biological Sciences Louisiana State University Baton Rouge LA 70803 USA
| | | | | | - Kyle E. Harms
- Department of Biological Sciences Louisiana State University Baton Rouge LA 70803 USA
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Traveset A, Richardson DM. Mutualistic Interactions and Biological Invasions. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2014. [DOI: 10.1146/annurev-ecolsys-120213-091857] [Citation(s) in RCA: 258] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mutualisms structure ecosystems and mediate their functioning. They also enhance invasions of many alien species. Invasions disrupt native mutualisms, often leading to population declines, reduced biodiversity, and altered ecosystem functioning. Focusing on three main types of mutualisms (pollination, seed dispersal, and plant-microbial symbioses) and drawing on examples from different ecosystems and from species- and community-level studies, we review the key mechanisms whereby such positive interactions mediate invasions and are in turn influenced by invasions. High interaction generalization is “the norm” in most systems, allowing alien species to infiltrate recipient communities. We identify traits that influence invasiveness (e.g., selfing capacity in plants, animal behavioral traits) or invasibility (e.g., partner choice in mycorrhizas/rhizobia) through mutualistic interactions. Mutualistic disruptions due to invasions are pervasive, and subsequent cascading effects are also widespread. Ecological networks provide a useful framework for predicting tipping points for community collapse in response to invasions and other synergistic drivers of global change.
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Affiliation(s)
- Anna Traveset
- Mediterranean Institute of Advanced Studies, E07190 Esporles, Mallorca, Balearic Islands, Spain
| | - David M. Richardson
- Centre for Invasion Biology, Department of Botany and Zoology, University of Stellenbosch, Matieland 7602, South Africa
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Del Vecchio S, Acosta A, Stanisci A. The impact of Acacia saligna invasion on Italian coastal dune EC habitats. C R Biol 2013; 336:364-9. [DOI: 10.1016/j.crvi.2013.06.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 05/28/2013] [Accepted: 06/17/2013] [Indexed: 11/30/2022]
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Plant-soil feedbacks do not explain invasion success of Acacia species in introduced range populations in Australia. Biol Invasions 2013. [DOI: 10.1007/s10530-013-0478-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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