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Holt JR, Cavichiolli de Oliveira N, Medina RF, Malacrinò A, Lindsey ARI. Insect-microbe interactions and their influence on organisms and ecosystems. Ecol Evol 2024; 14:e11699. [PMID: 39041011 PMCID: PMC11260886 DOI: 10.1002/ece3.11699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 06/14/2024] [Accepted: 06/21/2024] [Indexed: 07/24/2024] Open
Abstract
Microorganisms are important associates of insect and arthropod species. Insect-associated microbes, including bacteria, fungi, and viruses, can drastically impact host physiology, ecology, and fitness, while many microbes still have no known role. Over the past decade, we have increased our knowledge of the taxonomic composition and functional roles of insect-associated microbiomes and viromes. There has been a more recent shift toward examining the complexity of microbial communities, including how they vary in response to different factors (e.g., host genome, microbial strain, environment, and time), and the consequences of this variation for the host and the wider ecological community. We provide an overview of insect-microbe interactions, the variety of associated microbial functions, and the evolutionary ecology of these relationships. We explore the influence of the environment and the interactive effects of insects and their microbiomes across trophic levels. Additionally, we discuss the potential for subsequent synergistic and reciprocal impacts on the associated microbiomes, ecological interactions, and communities. Lastly, we discuss some potential avenues for the future of insect-microbe interactions that include the modification of existing microbial symbionts as well as the construction of synthetic microbial communities.
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Affiliation(s)
| | | | - Raul F. Medina
- Department of EntomologyTexas A&M University, Minnie Bell Heep CenterCollege StationTexasUSA
| | - Antonino Malacrinò
- Department of AgricultureUniversità Degli Studi Mediterranea di Reggio CalabriaReggio CalabriaItaly
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Chen JZ, Kwong Z, Gerardo NM, Vega NM. Ecological drift during colonization drives within-host and between-host heterogeneity in an animal-associated symbiont. PLoS Biol 2024; 22:e3002304. [PMID: 38662791 DOI: 10.1371/journal.pbio.3002304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 05/07/2024] [Accepted: 03/26/2024] [Indexed: 05/08/2024] Open
Abstract
Specialized host-microbe symbioses canonically show greater diversity than expected from simple models, both at the population level and within individual hosts. To understand how this heterogeneity arises, we utilize the squash bug, Anasa tristis, and its bacterial symbionts in the genus Caballeronia. We modulate symbiont bottleneck size and inoculum composition during colonization to demonstrate the significance of ecological drift, the noisy fluctuations in community composition due to demographic stochasticity. Consistent with predictions from the neutral theory of biodiversity, we found that ecological drift alone can account for heterogeneity in symbiont community composition between hosts, even when 2 strains are nearly genetically identical. When acting on competing strains, ecological drift can maintain symbiont genetic diversity among different hosts by stochastically determining the dominant strain within each host. Finally, ecological drift mediates heterogeneity in isogenic symbiont populations even within a single host, along a consistent gradient running the anterior-posterior axis of the symbiotic organ. Our results demonstrate that symbiont population structure across scales does not necessarily require host-mediated selection, as it can emerge as a result of ecological drift acting on both isogenic and unrelated competitors. Our findings illuminate the processes that might affect symbiont transmission, coinfection, and population structure in nature, which can drive the evolution of host-microbe symbioses and microbe-microbe interactions within host-associated microbiomes.
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Affiliation(s)
- Jason Z Chen
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
| | - Zeeyong Kwong
- Laboratory of Bacteriology, National Institutes of Allergy and Infectious Diseases, Hamilton, Montana, United States of America
| | - Nicole M Gerardo
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
| | - Nic M Vega
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
- Department of Physics, Emory University, Atlanta, Georgia, United States of America
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Stoy KS, Díaz-Almeyda EM, Bartelt C, Acosta A, Morran LT, Gerardo NM. Host-associated transmission favors transition of a commensal toward antagonism. Evolution 2023; 77:2512-2521. [PMID: 37739788 DOI: 10.1093/evolut/qpad173] [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: 01/18/2023] [Revised: 09/11/2023] [Accepted: 09/20/2023] [Indexed: 09/24/2023]
Abstract
The impacts of host-associated microbes on their hosts vary along a continuum of antagonistic, neutral, and beneficial interactions. Transmission mode is predicted to contribute to transitions along the continuum by altering opportunities for the alignment of host and microbe fitness interests. Under vertical transmission, microbial evolution is tightly coupled to the host environment, which may facilitate fitness alignment. In contrast, environmentally transmitted microbes spend time in the external environment, outside of hosts, partially decoupling their evolution from the host. This decoupling may misalign host and microbe fitness interests, potentially favoring antagonistic microbial traits. Here, we tested whether transmission environment alters microbial evolution by manipulating the interaction between a commensal Serratia marcescens bacteria and their insect host Anasa tristis, which is the primary vector of these bacteria into plants, where they cause disease. We experimentally evolved S. marcescens through several selection environments. The bacteria were passaged between A. tristis hosts, between A. tristis hosts and soil, through soil, or through standard culture media. We observed rapid evolution of virulence toward hosts across treatments when bacterial evolution occurred within the host environment, indicating that direct host-to-host transmission can increase opportunities for microbes to adapt to hosts and evolve antagonistic traits.
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Affiliation(s)
- Kayla S Stoy
- Emory University, Department of Biology, Atlanta, GA, United States
| | - Erika M Díaz-Almeyda
- Emory University, Department of Biology, Atlanta, GA, United States
- New College of Florida, Department of Natural Sciences, Sarasota, FL, United States
| | - Chris Bartelt
- Emory University, Department of Biology, Atlanta, GA, United States
| | - Alice Acosta
- Emory University, Department of Biology, Atlanta, GA, United States
| | - Levi T Morran
- Emory University, Department of Biology, Atlanta, GA, United States
| | - Nicole M Gerardo
- Emory University, Department of Biology, Atlanta, GA, United States
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Men Y, Yang ZW, Luo JY, Chen PP, Moreira FFF, Liu ZH, Yin JD, Xie BJ, Wang YH, Xie Q. Symbiotic Microorganisms and Their Different Association Types in Aquatic and Semiaquatic Bugs. Microbiol Spectr 2022; 10:e0279422. [PMID: 36409137 PMCID: PMC9769989 DOI: 10.1128/spectrum.02794-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 11/03/2022] [Indexed: 11/23/2022] Open
Abstract
True bugs (Hemiptera, suborder Heteroptera) constitute the largest suborder of nonholometabolous insects and occupy a wide range of habitats various from terrestrial to semiaquatic to aquatic niches. The transition and occupation of these diverse habitats impose various challenges to true bugs, including access to oxygen for the aquatic species and plant defense for the terrestrial phytophagans. Although numerous studies have demonstrated that microorganisms can provide multiple benefits to terrestrial host insects, a systematic study with comprehensive higher taxa sampling that represents aquatic and semiaquatic habitats is still lacking. To explore the role of symbiotic microorganisms in true bug adaptations, 204 samples belonging to all seven infraorders of Heteroptera were investigated, representing approximately 85% of its superfamilies and almost all known habitats. The symbiotic microbial communities of these insects were analyzed based on the full-length amplicons of the bacterial 16S rRNA gene and fungal ITS region. Bacterial communities varied among hosts inhabiting terrestrial, semiaquatic, and aquatic habitats, while fungal communities were more related to the geographical distribution of the hosts. Interestingly, co-occurrence networks showed that species inhabiting similar habitats shared symbiotic microorganism association types. Moreover, functional prediction analyses showed that the symbiotic bacterial community of aquatic species displayed richer amino acid and lipid metabolism pathways, while plant-feeding true bugs benefited more from the symbiont-provided xenobiotics biodegradation pathway. These results deepened the recognition that symbiotic microorganisms were likely to help heteropterans occupy diverse ecological habitats and provided a reference framework for further studies on how microorganisms affect host insects living in various habitats. IMPORTANCE Symbiotic bacteria and fungi generally colonize insects and provide various benefits for hosts. Although numerous studies have investigated symbionts in terrestrial plant-feeding insects, explorations of symbiotic bacterial and fungal communities in aquatic and semiaquatic insects are rare. In this study, the symbiotic microorganisms of 204 aquatic, semiaquatic, and terrestrial true bugs were explored. This comprehensive taxon sampling covers ~85% of the superfamilies of true bugs and most insect habitats. Analyses of the diversity of symbionts demonstrated that the symbiotic microbial diversities of true bugs were mainly affected by host habitats. Co-occurrence networks showed that true bugs inhabiting similar habitats shared symbiotic microbial association types. These correlations between symbionts and hosts together with the functions of bacterial communities indicated that symbiotic microbial communities may help true bugs adapt to (semi)aquatic habitats.
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Affiliation(s)
- Yu Men
- School of Life Sciences, State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Zi-wen Yang
- School of Life Sciences, State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Jiu-yang Luo
- School of Life Sciences, State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Ping-ping Chen
- Netherlands Centre of Biodiversity Naturalis, Leiden, Netherlands
| | | | - Zhi-hui Liu
- School of Life Sciences, State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Jia-dong Yin
- School of Life Sciences, State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Bao-jun Xie
- School of Life Sciences, State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yan-hui Wang
- School of Life Sciences, State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Qiang Xie
- School of Life Sciences, State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, Guangdong, China
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Berasategui A, Breitenbach N, García-Lozano M, Pons I, Sailer B, Lanz C, Rodríguez V, Hipp K, Ziemert N, Windsor D, Salem H. The leaf beetle Chelymorpha alternans propagates a plant pathogen in exchange for pupal protection. Curr Biol 2022; 32:4114-4127.e6. [PMID: 35987210 DOI: 10.1016/j.cub.2022.07.065] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/21/2022] [Accepted: 07/22/2022] [Indexed: 12/14/2022]
Abstract
Many insects rely on microbial protection in the early stages of their development. However, in contrast to symbiont-mediated defense of eggs and young instars, the role of microbes in safeguarding pupae remains relatively unexplored, despite the susceptibility of the immobile stage to antagonistic challenges. Here, we outline the importance of symbiosis in ensuring pupal protection by describing a mutualistic partnership between the ascomycete Fusarium oxysporum and Chelymorpha alternans, a leaf beetle. The symbiont rapidly proliferates at the onset of pupation, extensively and conspicuously coating C. alternans during metamorphosis. The fungus confers defense against predation as symbiont elimination results in reduced pupal survivorship. In exchange, eclosing beetles vector F. oxysporum to their host plants, resulting in a systemic infection. By causing wilt disease, the fungus retained its phytopathogenic capacity in light of its symbiosis with C. alternans. Despite possessing a relatively reduced genome, F. oxysporum encodes metabolic pathways that reflect its dual lifestyle as a plant pathogen and a defensive insect symbiont. These include virulence factors underlying plant colonization, along with mycotoxins that may contribute to the defensive biochemistry of the insect host. Collectively, our findings shed light on a mutualism predicated on pupal protection of an herbivorous beetle in exchange for symbiont dissemination and propagation.
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Affiliation(s)
- Aileen Berasategui
- Max Planck Institute for Biology, Mutualisms Research Group, Max-Planck-Ring 5, Tübingen 72076, Germany; University of Tübingen, Cluster of Excellence 'Controlling Microbes to Fight Infections', Auf der Morgenstelle 28, Tübingen 72076, Germany.
| | - Noa Breitenbach
- Max Planck Institute for Biology, Mutualisms Research Group, Max-Planck-Ring 5, Tübingen 72076, Germany
| | - Marleny García-Lozano
- Max Planck Institute for Biology, Mutualisms Research Group, Max-Planck-Ring 5, Tübingen 72076, Germany
| | - Inès Pons
- Max Planck Institute for Biology, Mutualisms Research Group, Max-Planck-Ring 5, Tübingen 72076, Germany
| | - Brigitte Sailer
- Max Planck Institute for Biology, Electron Microscopy Facility, Max-Planck-Ring 5, Tübingen 72076, Germany
| | - Christa Lanz
- Max Planck Institute for Biology, Genome Center, Max-Planck-Ring 5, Tübingen 72076, Germany
| | - Viterbo Rodríguez
- Centro Regional Universitario de Veraguas, Centro de Capacitación, Investigación y Monitoreo de la Biodiversidad en Coiba, Calle Décima, vía San Francisco, Santiago 08001, Republic of Panama
| | - Katharina Hipp
- Max Planck Institute for Biology, Electron Microscopy Facility, Max-Planck-Ring 5, Tübingen 72076, Germany
| | - Nadine Ziemert
- University of Tübingen, Cluster of Excellence 'Controlling Microbes to Fight Infections', Auf der Morgenstelle 28, Tübingen 72076, Germany
| | - Donald Windsor
- Smithsonian Tropical Research Institute, Luis Clement Avenue, Bldg. 401 Tupper, Panama City 0843-03092, Republic of Panama
| | - Hassan Salem
- Max Planck Institute for Biology, Mutualisms Research Group, Max-Planck-Ring 5, Tübingen 72076, Germany.
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