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Hudson CM, Stalder D, Vorburger C. Clines of resistance to parasitoids: the multifarious effects of temperature on defensive symbioses in insects. CURRENT OPINION IN INSECT SCIENCE 2024; 64:101208. [PMID: 38821141 DOI: 10.1016/j.cois.2024.101208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 05/02/2024] [Accepted: 05/24/2024] [Indexed: 06/02/2024]
Abstract
Insects are frequently infected with heritable bacterial endosymbionts. Some of them confer resistance to parasitoids. Such defensive symbionts are sensitive to variation in temperature. Drawing predominantly from the literature on aphids and flies, we show that temperature can affect the reliability of maternal transmission and the strength of protection provided by defensive symbionts. Costs of infection with defensive symbionts can also be temperature-dependent and may even turn into benefits under extreme temperatures, for example, when defensive symbionts increase heat tolerance. Alone or in combination, these mechanisms can drive temperature-associated (latitudinal) clines of infection prevalence with defensive symbionts. This has important consequences for host-parasitoid coevolution, as the relative importance of host-encoded vs. symbiont-provided defenses will shift along such clines.
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Affiliation(s)
- Cameron M Hudson
- Aquatic Ecology, Eawag, Überlandstrasse 133, P.O. Box 611, 8600 Dübendorf, Switzerland
| | - Dominic Stalder
- Aquatic Ecology, Eawag, Überlandstrasse 133, P.O. Box 611, 8600 Dübendorf, Switzerland; Institute of Integrative Biology, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland
| | - Christoph Vorburger
- Aquatic Ecology, Eawag, Überlandstrasse 133, P.O. Box 611, 8600 Dübendorf, Switzerland; Institute of Integrative Biology, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland.
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2
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Łukasik P, Kolasa MR. With a little help from my friends: the roles of microbial symbionts in insect populations and communities. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230122. [PMID: 38705185 PMCID: PMC11070262 DOI: 10.1098/rstb.2023.0122] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Accepted: 12/14/2023] [Indexed: 05/07/2024] Open
Abstract
To understand insect abundance, distribution and dynamics, we need to understand the relevant drivers of their populations and communities. While microbial symbionts are known to strongly affect many aspects of insect biology, we lack data on their effects on populations or community processes, or on insects' evolutionary responses at different timescales. How these effects change as the anthropogenic effects on ecosystems intensify is an area of intense research. Recent developments in sequencing and bioinformatics permit cost-effective microbial diversity surveys, tracking symbiont transmission, and identification of functions across insect populations and multi-species communities. In this review, we explore how different functional categories of symbionts can influence insect life-history traits, how these effects could affect insect populations and their interactions with other species, and how they may affect processes and patterns at the level of entire communities. We argue that insect-associated microbes should be considered important drivers of insect response and adaptation to environmental challenges and opportunities. We also outline the emerging approaches for surveying and characterizing insect-associated microbiota at population and community scales. This article is part of the theme issue 'Towards a toolkit for global insect biodiversity monitoring'.
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Affiliation(s)
- Piotr Łukasik
- Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, 30-387 Krakow, Poland
| | - Michał R. Kolasa
- Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, 30-387 Krakow, Poland
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3
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Maeda GP, Kelly MK, Sundar A, Moran NA. Intracellular defensive symbiont is culturable and capable of transovarial, vertical transmission. mBio 2024; 15:e0325323. [PMID: 38712948 PMCID: PMC11237597 DOI: 10.1128/mbio.03253-23] [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: 12/02/2023] [Accepted: 04/04/2024] [Indexed: 05/08/2024] Open
Abstract
Insects frequently form heritable associations with beneficial bacteria that are vertically transmitted from parent to offspring. Long-term vertical transmission has repeatedly resulted in genome reduction and gene loss, rendering many such bacteria incapable of establishment in axenic culture. Among aphids, heritable endosymbionts often provide context-specific benefits to their hosts. Although these associations have large impacts on host phenotypes, experimental approaches are often limited by an inability to cultivate these microbes. Here, we report the axenic culture of Candidatus Fukatsuia symbiotica strain WIR, a heritable bacterial endosymbiont of the pea aphid, Acyrthosiphon pisum. Whole-genome sequencing revealed similar genomic features and high sequence similarity to previously described strains, suggesting that the cultivation techniques used here may be applicable to Ca. F. symbiotica strains from distantly related aphids. Microinjection of cultured Ca. F. symbiotica into uninfected aphids revealed that it can reinfect developing embryos and that infections are maintained in subsequent generations via transovarial maternal transmission. Artificially infected aphids exhibit phenotypic and life history traits similar to those observed for native infections. Our results show that Ca. F. symbiotica may be a useful tool for experimentally probing the molecular mechanisms underlying host-symbiont interactions in a heritable symbiosis. IMPORTANCE Diverse eukaryotic organisms form stable, symbiotic relationships with bacteria that provide benefits to their hosts. While these associations are often biologically important, they can be difficult to probe experimentally because intimately host-associated bacteria are difficult to access within host tissues, and most cannot be cultured. This is especially true for the intracellular, maternally inherited bacteria associated with many insects, including aphids. Here, we demonstrate that a pea aphid-associated strain of the heritable endosymbiont, Candidatus Fukatsuia symbiotica, can be grown outside of its host using standard microbiology techniques and can readily re-establish infection that is maintained across host generations. These artificial infections recapitulate the effects of native infections, making this host-symbiont pair a useful experimental system.
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Affiliation(s)
- Gerald P. Maeda
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas, USA
| | - Mary Katherine Kelly
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas, USA
| | - Aadhunik Sundar
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas, USA
| | - Nancy A. Moran
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas, USA
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4
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Chirgwin E, Yang Q, Umina PA, Thia JA, Gill A, Song W, Gu X, Ross PA, Wei SJ, Hoffmann AA. Barley Yellow Dwarf Virus Influences Its Vector's Endosymbionts but Not Its Thermotolerance. Microorganisms 2023; 12:10. [PMID: 38276179 PMCID: PMC10819152 DOI: 10.3390/microorganisms12010010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 12/11/2023] [Accepted: 12/14/2023] [Indexed: 01/27/2024] Open
Abstract
The barley yellow dwarf virus (BYDV) of cereals is thought to substantially increase the high-temperature tolerance of its aphid vector, Rhopalosiphum padi, which may enhance its transmission efficiency. This is based on experiments with North American strains of BYDV and R. padi. Here, we independently test these by measuring the temperature tolerance, via Critical Thermal Maximum (CTmax) and knockdown time, of Australian R. padi infected with a local BYDV isolate. We further consider the interaction between BYDV transmission, the primary endosymbiont of R. padi (Buchnera aphidicola), and a transinfected secondary endosymbiont (Rickettsiella viridis) which reduces the thermotolerance of other aphid species. We failed to find an increase in tolerance to high temperatures in BYDV-infected aphids or an impact of Rickettsiella on thermotolerance. However, BYDV interacted with R. padi endosymbionts in unexpected ways, suppressing the density of Buchnera and Rickettsiella. BYDV density was also fourfold higher in Rickettsiella-infected aphids. Our findings indicate that BYDV does not necessarily increase the temperature tolerance of the aphid transmission vector to increase its transmission potential, at least for the genotype combinations tested here. The interactions between BYDV and Rickettsiella suggest new ways in which aphid endosymbionts may influence how BYDV spreads, which needs further testing in a field context.
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Affiliation(s)
- Evatt Chirgwin
- Cesar Australia, 95 Albert Street, Brunswick, VIC 3056, Australia;
| | - Qiong Yang
- PEARG Group, School of BioSciences, Bio21 Institute, The University of Melbourne, Parkville, VIC 2052, Australia; (J.A.T.); (A.G.); (X.G.); (P.A.R.); (A.A.H.)
| | - Paul A. Umina
- Cesar Australia, 95 Albert Street, Brunswick, VIC 3056, Australia;
- PEARG Group, School of BioSciences, Bio21 Institute, The University of Melbourne, Parkville, VIC 2052, Australia; (J.A.T.); (A.G.); (X.G.); (P.A.R.); (A.A.H.)
| | - Joshua A. Thia
- PEARG Group, School of BioSciences, Bio21 Institute, The University of Melbourne, Parkville, VIC 2052, Australia; (J.A.T.); (A.G.); (X.G.); (P.A.R.); (A.A.H.)
| | - Alex Gill
- PEARG Group, School of BioSciences, Bio21 Institute, The University of Melbourne, Parkville, VIC 2052, Australia; (J.A.T.); (A.G.); (X.G.); (P.A.R.); (A.A.H.)
| | - Wei Song
- Institute of Plant Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China; (W.S.); (S.-J.W.)
| | - Xinyue Gu
- PEARG Group, School of BioSciences, Bio21 Institute, The University of Melbourne, Parkville, VIC 2052, Australia; (J.A.T.); (A.G.); (X.G.); (P.A.R.); (A.A.H.)
| | - Perran A. Ross
- PEARG Group, School of BioSciences, Bio21 Institute, The University of Melbourne, Parkville, VIC 2052, Australia; (J.A.T.); (A.G.); (X.G.); (P.A.R.); (A.A.H.)
| | - Shu-Jun Wei
- Institute of Plant Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China; (W.S.); (S.-J.W.)
| | - Ary A. Hoffmann
- PEARG Group, School of BioSciences, Bio21 Institute, The University of Melbourne, Parkville, VIC 2052, Australia; (J.A.T.); (A.G.); (X.G.); (P.A.R.); (A.A.H.)
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5
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Martins M, César CS, Cogni R. The effects of temperature on prevalence of facultative insect heritable symbionts across spatial and seasonal scales. Front Microbiol 2023; 14:1321341. [PMID: 38143870 PMCID: PMC10741647 DOI: 10.3389/fmicb.2023.1321341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 11/23/2023] [Indexed: 12/26/2023] Open
Abstract
Facultative inheritable endosymbionts are common and diverse in insects and are often found at intermediate frequencies in insect host populations. The literature assessing the relationship between environment and facultative endosymbiont frequency in natural host populations points to temperature as a major component shaping the interaction. However, a synthesis describing its patterns and mechanistic basis is lacking. This mini-review aims to bridge this gap by, following an evolutionary model, hypothesizing that temperature increases endosymbiont frequencies by modulating key phenotypes mediating the interaction. Field studies mainly present positive correlations between temperature and endosymbiont frequency at spatial and seasonal scales; and unexpectedly, temperature is predominantly negatively correlated with the key phenotypes. Higher temperatures generally reduce the efficiency of maternal transmission, reproductive parasitism, endosymbiont influence on host fitness and the ability to protect against natural enemies. From the endosymbiont perspective alone, higher temperatures reduce titer and both high and low temperatures modulate their ability to promote host physiological acclimation and behavior. It is necessary to promote research programs that integrate field and laboratory approaches to pinpoint which processes are responsible for the temperature correlated patterns of endosymbiont prevalence in natural populations.
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Affiliation(s)
| | | | - Rodrigo Cogni
- Department of Ecology, University of São Paulo, São Paulo, Brazil
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6
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Maeda GP, Kelly MK, Sundar A, Moran NA. Intracellular defensive symbiont is culturable and capable of transovarial, vertical transmission. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.05.570145. [PMID: 38106215 PMCID: PMC10723312 DOI: 10.1101/2023.12.05.570145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Insects frequently form heritable associations with beneficial bacteria that are vertically transmitted from parent to offspring. Long term vertical transmission has repeatedly resulted in genome reduction and gene loss rendering many such bacteria incapable of independent culture. Among aphids, heritable endosymbionts often provide a wide range of context-specific benefits to their hosts. Although these associations have large impacts on host phenotypes, experimental approaches are often limited by an inability to independently cultivate these microbes. Here, we report the axenic culture of Candidatus Fukatsuia symbiotica strain WIR, a heritable bacterial endosymbiont of the pea aphid, Acyrthosiphon pisum . Whole genome sequencing revealed similar genomic features and high sequence similarity to previously described strains, suggesting the cultivation techniques used here may be applicable to Ca . F. symbiotica strains from distantly related aphids. Microinjection of the isolated strain into uninfected aphids revealed that it can reinfect developing embryos, and is maintained in subsequent generations via transovarial maternal transmission. Artificially infected aphids exhibit similar phenotypic and life history traits compared to native infections, including protective effects against an entomopathogenic Fusarium species. Overall, our results show that Ca . F. symbiotica may be a useful tool for experimentally probing the molecular mechanisms underlying heritable symbioses and antifungal defense in the pea aphid system. IMPORTANCE Diverse eukaryotic organisms form stable, symbiotic relationships with bacteria that provide benefits to their hosts. While these associations are often biologically important, they can be difficult to probe experimentally, because intimately host-associated bacteria are difficult to access within host tissues, and most cannot be cultured. This is especially true of the intracellular, maternally inherited bacteria associated with many insects, including aphids. Here, we demonstrate that a pea aphid-associated strain of the heritable endosymbiont, Candidatus Fukatsuia symbiotica, can be grown outside of its host using standard microbiology techniques, and can readily re-establish infection that is maintained across host generations. These artificial infections recapitulate the effects of native infections making this host-symbiont pair a useful experimental system. Using this system, we demonstrate that Ca . F. symbiotica infection reduces host fitness under benign conditions, but protects against a previously unreported fungal pathogen.
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7
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Patel V, Lynn-Bell N, Chevignon G, Kucuk RA, Higashi CHV, Carpenter M, Russell JA, Oliver KM. Mobile elements create strain-level variation in the services conferred by an aphid symbiont. Environ Microbiol 2023; 25:3333-3348. [PMID: 37864320 DOI: 10.1111/1462-2920.16520] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 09/27/2023] [Indexed: 10/22/2023]
Abstract
Heritable, facultative symbionts are common in arthropods, often functioning in host defence. Despite moderately reduced genomes, facultative symbionts retain evolutionary potential through mobile genetic elements (MGEs). MGEs form the primary basis of strain-level variation in genome content and architecture, and often correlate with variability in symbiont-mediated phenotypes. In pea aphids (Acyrthosiphon pisum), strain-level variation in the type of toxin-encoding bacteriophages (APSEs) carried by the bacterium Hamiltonella defensa correlates with strength of defence against parasitoids. However, co-inheritance creates difficulties for partitioning their relative contributions to aphid defence. Here we identified isolates of H. defensa that were nearly identical except for APSE type. When holding H. defensa genotype constant, protection levels corresponded to APSE virulence module type. Results further indicated that APSEs move repeatedly within some H. defensa clades providing a mechanism for rapid evolution in anti-parasitoid defences. Strain variation in H. defensa also correlates with the presence of a second symbiont Fukatsuia symbiotica. Predictions that nutritional interactions structured this coinfection were not supported by comparative genomics, but bacteriocin-containing plasmids unique to co-infecting strains may contribute to their common pairing. In conclusion, strain diversity, and joint capacities for horizontal transfer of MGEs and symbionts, are emergent players in the rapid evolution of arthropods.
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Affiliation(s)
- Vilas Patel
- Department of Entomology, University of Georgia, Athens, Georgia, USA
| | - Nicole Lynn-Bell
- Department of Entomology, University of Georgia, Athens, Georgia, USA
| | - Germain Chevignon
- Laboratoire de Génétique et Pathologie des Mollusques Marins, IFREMER, La Tremblade, France
| | - Roy A Kucuk
- Department of Entomology, University of Georgia, Athens, Georgia, USA
| | | | - Melissa Carpenter
- Department of Biodiversity, Earth, and Environmental Science, Drexel University, Philadelphia, Pennsylvania, USA
| | - Jacob A Russell
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, USA
| | - Kerry M Oliver
- Department of Entomology, University of Georgia, Athens, Georgia, USA
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8
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Jahan H, Khudr MS, Arafeh A, Hager R. Exposure to heat stress leads to striking clone-specific nymph deformity in pea aphid. PLoS One 2023; 18:e0282449. [PMID: 37883483 PMCID: PMC10602343 DOI: 10.1371/journal.pone.0282449] [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: 02/14/2023] [Accepted: 06/15/2023] [Indexed: 10/28/2023] Open
Abstract
Climatic changes, such as heatwaves, pose unprecedented challenges for insects, as escalated temperatures above the thermal optimum alter insect reproductive strategies and energy metabolism. While thermal stress responses have been reported in different insect species, thermo-induced developmental abnormalities in phloem-feeding pests are largely unknown. In this laboratory study, we raised two groups of first instar nymphs belonging to two clones of the pea aphid Acyrthosiphon pisum, on fava beans Vicia faba. The instars developed and then asexually reproduced under constant exposure to a sub-lethal heatwave (27°C) for 14 days. Most mothers survived but their progenies showed abnormalities, as stillbirths and appendageless or weak nymphs with folded appendages were delivered. Clone N116 produced more deceased and appendageless embryos, contrary to N127, which produced fewer dead and more malformed premature embryos. Interestingly, the expression of the HSP70 and HSP83 genes differed in mothers between the clones. Moreover, noticeable changes in metabolism, e.g., lipids, were also detected and that differed in response to stress. Deformed offspring production after heat exposure may be due to heat injury and differential HSP gene expression, but may also be indicative of a conflict between maternal and offspring fitness. Reproductive altruism might have occurred to ensure some of the genetically identical daughters survive. This is because maintaining homeostasis and complete embryogenesis could not be simultaneously fulfilled due to the high costs of stress. Our findings shine new light on pea aphid responses to heatwaves and merit further examination across different lineages and species.
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Affiliation(s)
- Hawa Jahan
- Faculty of Biology, Medicine and Health, Division of Evolution, Infection and Genomics, School of Biological Sciences, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
- Faculty of Biological Sciences, Department of Zoology, University of Dhaka, Dhaka, Bangladesh
| | - Mouhammad Shadi Khudr
- Faculty of Biology, Medicine and Health, Division of Evolution, Infection and Genomics, School of Biological Sciences, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
| | - Ali Arafeh
- Faculty of Science and Engineering, Chemical Engineering, James Chadwick Building, The University of Manchester, Manchester, United Kingdom
| | - Reinmar Hager
- Faculty of Biology, Medicine and Health, Division of Evolution, Infection and Genomics, School of Biological Sciences, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
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9
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Mason CJ, Shikano I. Hotter days, stronger immunity? Exploring the impact of rising temperatures on insect gut health and microbial relationships. CURRENT OPINION IN INSECT SCIENCE 2023; 59:101096. [PMID: 37517588 DOI: 10.1016/j.cois.2023.101096] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 07/07/2023] [Accepted: 07/25/2023] [Indexed: 08/01/2023]
Abstract
Climate change can generate cascading effects on animals through compounding stressors. As ectotherms, insects are particularly susceptible to variation in temperature and extreme events. How insects respond to temperature often occurs with respect to their environment, and a pertinent question involves how thermal stress integrates with insect capabilities to resolve interactions with gut microorganisms (microbiome and gut pathogens). We explore the impact of elevated temperatures and the impact of the host physiological response influencing immune system regulation and the gut microbiome. We summarize the literature involving how elevated temperature extremes impact insect gut immune systems, and how in turn that alters potential interactions with the gut microbiome and potential pathogens. Temperature effects on immunity are complex, and ultimate effects on microbial components can vary by system. Moreover, there are multiple questions yet to explore in how insects contend with simultaneous abiotic stressors and potential trade-offs in their response to opportunistic microbiota.
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Affiliation(s)
- Charles J Mason
- Tropical Pest Genetics and Molecular Biology Research Unit, Daniel K Inouye U.S. Pacific Basin Agricultural Research Center, Agricultural Research Service, USDA, 64 Nowelo Street, Hilo, HI 96720, USA
| | - Ikkei Shikano
- Department of Plant and Environmental Protection Sciences, College of Tropical Agriculture and Human Resources, University of Hawai'i at Mānoa, 3050 Maile Way, Gilmore Hall 513, Honolulu, HI 96822, USA.
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10
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Yang K, Qin PH, Yuan MY, Chen L, Zhang YJ, Chu D. Infection density pattern of Cardinium affects the responses of bacterial communities in an invasive whitefly under heat conditions. INSECT SCIENCE 2023; 30:1149-1164. [PMID: 36331043 DOI: 10.1111/1744-7917.13141] [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: 06/11/2022] [Revised: 10/19/2022] [Accepted: 10/24/2022] [Indexed: 06/16/2023]
Abstract
Communities of bacteria, especially symbionts, are vital for the growth and development of insects and other arthropods, including Bemisia tabaci Mediterranean (MED), a destructive and invasive insect pest. However, the infection density patterns and influence factors of bacteria in whiteflies, which mainly include symbionts, remain largely unclear. To reveal the different density patterns of Cardinium in B. tabaci MED populations and the impacts of high temperatures on whiteflies with different Cardinium density infection patterns, 2 isofemale lines isolated from B. tabaci MED from the same geographical population of China and from B. tabaci MED collected from other countries and locations were examined using several techniques and methods, including fluorescence in situ hybridization (FISH), quantitative real-time polymerase chain reaction (qPCR), 16S rRNA gene sequencing, and 2b-RAD sequencing. The results showed that there were 2 different infection density patterns of Cardinium in B. tabaci MED (including 1 high-density pattern and 1 low-density pattern). For whiteflies with low-density Cardinium, conventional PCR could not detect Cardinium, but the other techniques confirmed that there was a low level of Cardinium within hosts. High temperature significantly decreased the diversity of bacterial communities: the relative titer of Cardinium increased but the density of Rickettsia decreased in the isofemale line with high-density Cardinium. However, high temperature did not influence the diversity and symbiont density in the line with low-density Cardinium. Moreover, high temperature influenced the functions of bacterial communities in whiteflies with high-density Cardinium but did not affect the bacterial functions in whiteflies with low-density Cardinium. Our results provide novel insights into the complex associations between symbionts and host insects.
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Affiliation(s)
- Kun Yang
- Shandong Engineering Research Center for Environment-Friendly Agricultural Pest Management, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, Shandong Province, China
| | - Peng-Hao Qin
- Shandong Engineering Research Center for Environment-Friendly Agricultural Pest Management, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, Shandong Province, China
| | - Meng-Ying Yuan
- Shandong Engineering Research Center for Environment-Friendly Agricultural Pest Management, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, Shandong Province, China
| | - Lei Chen
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
| | - You-Jun Zhang
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Dong Chu
- Shandong Engineering Research Center for Environment-Friendly Agricultural Pest Management, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, Shandong Province, China
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11
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Blanton AG, Perkins S, Peterson BF. In vitro assays reveal inherently insecticide-tolerant termite symbionts. Front Physiol 2023; 14:1134936. [PMID: 37501931 PMCID: PMC10368989 DOI: 10.3389/fphys.2023.1134936] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 06/30/2023] [Indexed: 07/29/2023] Open
Abstract
Introduction: Termite symbionts are well known for conferring a myriad of benefits to their hosts. Bacterial symbionts are repeatedly associated with increased fitness, nutritional supplementation, pathogen protection, and proper development across insect taxa. In addition, several recent studies link bacterial symbionts to reduced insecticide efficacy. This has important implications both in pest control management and environmental bioremediation efforts. Insects' guts may be a valuable resource for microbes with broad application given their unique niches and metabolic diversity. Though insecticide resistance in termites is considered unlikely due to their life history, the close association of termites with a multitude of bacteria raises the question: is there potential for symbiont-mediated pesticide tolerance in termites? Methods and results: We identified a candidate that could grow in minimal medium containing formulated pesticide. This bacterial isolate was then subjected to continuous culture and subsequently demonstrated improved performance in the presence of pesticide. Isolates subjected to continuous culture were then grown at a range of concentrations from 1-10X the formulation rate. After constant exposure for several generations, isolates grew significantly better. Conclusion: Here we demonstrate that naïve insect hosts can harbor symbionts with inherent insecticide tolerance capable of rapid adaptation to increasing insecticide concentrations overtime. This has broad implications for both pest control and environmental cleanup of residual pesticides.
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12
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Tian PP, Zhang YL, Huang JL, Li WY, Liu XD. Arsenophonus Interacts with Buchnera to Improve Growth Performance of Aphids under Amino Acid Stress. Microbiol Spectr 2023; 11:e0179223. [PMID: 37222634 PMCID: PMC10269474 DOI: 10.1128/spectrum.01792-23] [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: 04/28/2023] [Accepted: 05/09/2023] [Indexed: 05/25/2023] Open
Abstract
Amino acids play a crucial role in the growth and development of insects. Aphids cannot ingest enough amino acids in plant phloem to meet their requirements, and therefore, they are mainly dependent on the obligate symbiont Buchnera aphidicola to synthesize essential amino acids. Besides Buchnera, aphids may harbor another facultative symbiont, Arsenophonus, which alters the requirement of the cotton-melon aphid Aphis gossypii for amino acid. However, it is unclear how Arsenophonus regulates the requirement. Here, we found that Arsenophonus ameliorated growth performance of A. gossypii on an amino acid-deficient diet. A deficiency in lysine (Lys) or methionine (Met) led to changes in the abundance of Arsenophonus. Arsenophonus suppressed the abundance of Buchnera when aphids were fed a normal amino acid diet, but this suppression was eliminated or reversed when aphids were on a Lys- or Met-deficient diet. The relative abundance of Arsenophonus was positively correlated with that of Buchnera, but neither of them was correlated with the body weight of aphids. The relative expression levels of Lys and Met synthase genes of Buchnera were affected by the interaction between Arsenophonus infections and Buchnera abundance, especially in aphids reared on a Lys- or Met-deficient diet. Arsenophonus coexisted with Buchnera in bacteriocytes, which strengthens the interaction. IMPORTANCE The obligate symbiont Buchnera can synthesize amino acids for aphids. In this study, we found that a facultative symbiont, Arsenophonus, can help improve aphids' growth performance under amino acid deficiency stress by changing the relative abundance of Buchnera and the expression levels of amino acid synthase genes. This study highlights the interaction between Arsenophonus and Buchnera to ameliorate aphid growth under amino acid stress.
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Affiliation(s)
- Pan-Pan Tian
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
| | - Yu-Lin Zhang
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
| | - Jing-Ling Huang
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
| | - Wang-Yan Li
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
| | - Xiang-Dong Liu
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
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13
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Tougeron K, Iltis C, Rampnoux E, Goerlinger A, Dhondt L, Hance T. Still standing: The heat protection delivered by a facultative symbiont to its aphid host is resilient to repeated thermal stress. CURRENT RESEARCH IN INSECT SCIENCE 2023; 3:100061. [PMID: 37304568 PMCID: PMC10250925 DOI: 10.1016/j.cris.2023.100061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 04/05/2023] [Accepted: 05/29/2023] [Indexed: 06/13/2023]
Abstract
Insects have evolved diverse strategies to resist extreme high temperatures (EHT). The adaptive value of such strategies has to be evaluated when organisms experience multiple EHT events during their lifetime, as predicted in a changing climate. This is particularly the case for associations with facultative microbial partners involved in insect heat tolerance, the resilience of which to repeated heat stress has never been studied. We compared two artificial lines of the pea aphid (Acyrthosiphon pisum) differing by the absence or presence of the heat-protective facultative bacterium Serratia symbiotica. We exposed insect nymphs to a varying number of EHT events (between 0 and 3), and recorded fitness parameters. Except survival traits, fitness estimates were affected by the interaction between aphid infection status (absence/presence of S. symbiotica) and thermal treatment (number of heat shocks applied). Costs of bacterial infection were detected in the absence of thermal stress: symbiont-hosting aphids incurred longer development, decreased fecundity and body size. However, symbiotic infection turned neutral, and even beneficial for some traits (development and body size), as the number of heat shocks increased, and compared to the aposymbiotic strain. Conversely, symbiotic infection mediated aphid response to heat shock(s): fitness decreased only in the uninfected group. These findings suggest that (i) the facultative symbiont may alternatively act as a pathogen, commensal or mutualist depending on thermal environment, and (ii) the heat protection it delivered to its host persists under frequent EHT. We discuss eco-evolutionary implications and the role of potentially confounding factors (stage-specific effects, genetic polymorphism displayed by the obligate symbiont).
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Affiliation(s)
- Kévin Tougeron
- Earth and Life Institute, Ecology and Biodiversity, Université catholique de Louvain, Croix du Sud 4-5, 1348 Louvain-la-Neuve, Belgium
- Institut de Recherche en Biosciences, Université de Mons, Av. du Champ de Mars 6, 7000 Mons, Belgium
| | - Corentin Iltis
- Earth and Life Institute, Ecology and Biodiversity, Université catholique de Louvain, Croix du Sud 4-5, 1348 Louvain-la-Neuve, Belgium
| | - Eliott Rampnoux
- Earth and Life Institute, Ecology and Biodiversity, Université catholique de Louvain, Croix du Sud 4-5, 1348 Louvain-la-Neuve, Belgium
| | - Alexandre Goerlinger
- Earth and Life Institute, Ecology and Biodiversity, Université catholique de Louvain, Croix du Sud 4-5, 1348 Louvain-la-Neuve, Belgium
| | - Linda Dhondt
- Earth and Life Institute, Ecology and Biodiversity, Université catholique de Louvain, Croix du Sud 4-5, 1348 Louvain-la-Neuve, Belgium
| | - Thierry Hance
- Earth and Life Institute, Ecology and Biodiversity, Université catholique de Louvain, Croix du Sud 4-5, 1348 Louvain-la-Neuve, Belgium
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14
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Gimmi E, Wallisch J, Vorburger C. Defensive symbiosis in the wild: Seasonal dynamics of parasitism risk and symbiont-conferred resistance. Mol Ecol 2023. [PMID: 37160764 DOI: 10.1111/mec.16976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 04/19/2023] [Accepted: 04/25/2023] [Indexed: 05/11/2023]
Abstract
Parasite-mediated selection can rapidly drive up resistance levels in host populations, but fixation of resistance traits may be prevented by costs of resistance. Black bean aphids (Aphis fabae) benefit from increased resistance to parasitoids when carrying the defensive bacterial endosymbiont Hamiltonella defensa. However, due to fitness costs that come with symbiont infection, symbiont-conferred resistance may result in either a net benefit or a net cost to the aphid host, depending on parasitoid presence as well as on the general ecological context. Balancing selection may therefore explain why in natural aphid populations, H. defensa is often found at intermediate frequencies. Here we present a 2-year field study where we set out to look for signatures of balancing selection in natural aphid populations. We collected temporally well-resolved data on the prevalence of H. defensa in A. f. fabae and estimated the risk imposed by parasitoids using sentinel hosts. Despite a marked and consistent early-summer peak in parasitism risk, and significant changes in symbiont prevalence over time, we found just a weak correlation between parasitism risk and H. defensa frequency dynamics. H. defensa prevalence in the populations under study was, in fact, better explained by the number of heat days that previous aphid generations were exposed to. Our study grants an unprecedentedly well-resolved insight into the dynamics of endosymbiont and parasitoid communities of A. f. fabae populations, and it adds to a growing body of empirical evidence suggesting that not only parasitism risk, but rather multifarious selection is shaping H. defensa prevalence in the wild.
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Affiliation(s)
- Elena Gimmi
- Department of Aquatic Ecology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
- D-USYS, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Jesper Wallisch
- Department of Aquatic Ecology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Christoph Vorburger
- Department of Aquatic Ecology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
- D-USYS, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
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15
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Kaszyca-Taszakowska N, Depa Ł. Microbiome of the Aphid Genus Dysaphis Börner (Hemiptera: Aphidinae) and Its Relation to Ant Attendance. INSECTS 2022; 13:insects13121089. [PMID: 36554999 PMCID: PMC9781600 DOI: 10.3390/insects13121089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 11/22/2022] [Accepted: 11/22/2022] [Indexed: 05/19/2023]
Abstract
Among mutualistic relationships of aphids with other organisms, there are two that seem to be of major importance: trophobiosis with ants and endosymbiosis of bacteria. While the former is well studied, the latter is the subject of an increasing amount of research constantly revealing new aspects of this symbiosis. Here, we studied the possible influence of ant attendance on the composition of aphid microbiota on primary and secondary hosts exploited by the aphid genus Dysaphis. The microbiome of 44 samples representing 12 aphid species was studied using an Illumina HiSeq 4000 with the V3-V4 region of 16S rRNA. The results showed a higher abundance of common facultative symbionts (Serratia, Regiella, Fukatsuia) in aphid species unattended by ants, but also on secondary hosts. However, in colonies attended by ants, the general species composition of bacterial symbionts was more rich in genera than in unattended colonies (Wolbachia, Gilliamella, Spiroplasma, Sphingomonas, Pelomonas). The results indicate a huge variability of facultative symbionts without clear correlation with ant attendance or aphid species. The possibility of multiple routes of bacterial infection mediated by ant-made environmental conditions is discussed.
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16
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Li T, Wei Y, Zhao C, Li S, Gao S, Zhang Y, Wu Y, Lu C. Facultative symbionts are potential agents of symbiont-mediated RNAi in aphids. Front Microbiol 2022; 13:1020461. [PMID: 36504780 PMCID: PMC9727308 DOI: 10.3389/fmicb.2022.1020461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 11/07/2022] [Indexed: 11/24/2022] Open
Abstract
Aphids are major crop pests, and they can be controlled through the application of the promising RNA interference (RNAi) techniques. However, chemical synthesis yield of dsRNA for RNAi is low and costly. Another sustainable aphid pest control strategy takes advantage of symbiont-mediated RNAi (SMR), which can generate dsRNA by engineered microbes. Aphid host the obligate endosymbiont Buchnera aphidicola and various facultative symbionts that not only have a wide host range but are also vertically and horizontally transmitted. Thus, we described the potential of facultative symbionts in aphid pest control by SMR. We summarized the community and host range of these facultative symbionts, and then reviewed their probable horizontal transmitted routes and ecological functions. Moreover, recent advances in the cultivation and genetic engineering of aphid facultative symbionts were discussed. In addition, current legislation of dsRNA-based pest control strategies and their safety assessments were reviewed.
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Affiliation(s)
- Tong Li
- Institute of Plant Protection, Henan Key Laboratory of Crop Pest Control/Key Laboratory of Integrated Pest Management on Crops in Southern Region of North China, Henan Academy of Agricultural Sciences, Zhengzhou, China
| | - Yongjun Wei
- School of Pharmaceutical Sciences, Laboratory of Synthetic Biology, Zhengzhou University, Zhengzhou, China
| | - Chenchen Zhao
- Henan International Laboratory for Green Pest Control /College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Shaojian Li
- Institute of Plant Protection, Henan Key Laboratory of Crop Pest Control/Key Laboratory of Integrated Pest Management on Crops in Southern Region of North China, Henan Academy of Agricultural Sciences, Zhengzhou, China
| | - Suxia Gao
- Institute of Plant Protection, Henan Key Laboratory of Crop Pest Control/Key Laboratory of Integrated Pest Management on Crops in Southern Region of North China, Henan Academy of Agricultural Sciences, Zhengzhou, China
| | - Yuanchen Zhang
- College of Biological and Food Engineering, Anyang Institute of Technology, Anyang, China
| | - Yuqing Wu
- Institute of Plant Protection, Henan Key Laboratory of Crop Pest Control/Key Laboratory of Integrated Pest Management on Crops in Southern Region of North China, Henan Academy of Agricultural Sciences, Zhengzhou, China
| | - Chuantao Lu
- Institute of Plant Protection, Henan Key Laboratory of Crop Pest Control/Key Laboratory of Integrated Pest Management on Crops in Southern Region of North China, Henan Academy of Agricultural Sciences, Zhengzhou, China,Chuantao Lu
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17
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Hafsi A, Delatte H. Enterobactereaceae symbiont as facilitators of biological invasion: review on Tephritidae fruit flies. Biol Invasions 2022. [DOI: 10.1007/s10530-022-02960-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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18
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Clavé C, Sugio A, Morlière S, Pincebourde S, Simon J, Foray V. Physiological costs of facultative endosymbionts in aphids assessed from energy metabolism. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Corentin Clavé
- Institut de Recherche sur la Biologie de l’Insecte, UMR 7261, CNRS Université de Tours Tours France
- Department of Agricultural Sciences University of Naples Federico II Portici Italy
| | - Akiko Sugio
- IGEPP, Agrocampus Ouest, INRA Université de Rennes 1 Le Rheu France
| | | | - Sylvain Pincebourde
- Institut de Recherche sur la Biologie de l’Insecte, UMR 7261, CNRS Université de Tours Tours France
| | | | - Vincent Foray
- Institut de Recherche sur la Biologie de l’Insecte, UMR 7261, CNRS Université de Tours Tours France
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19
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McMunn MS, Hudson AI, Zemenick AT, Egerer M, Bennett L, Philpott SM, Vannette RL. Thermal sensitivity and seasonal change in the gut microbiome of a desert ant, Cephalotes rohweri. FEMS Microbiol Ecol 2022; 98:6596280. [PMID: 35641145 DOI: 10.1093/femsec/fiac062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 05/12/2022] [Accepted: 05/24/2022] [Indexed: 11/14/2022] Open
Abstract
Microorganisms within ectotherms must withstand the variable body temperatures of their hosts. Shifts in host body temperature resulting from climate change have the potential to shape ectotherm microbiome composition. Microbiome compositional changes occurring in response to temperature in nature have not been frequently examined, restricting our ability to predict microbe-mediated ectotherm responses to climate change. In a set of field-based observations, we characterized gut bacterial communities and thermal exposure across a population of desert arboreal ants (Cephalotes rohweri). In a paired growth chamber experiment, we exposed ant colonies to variable temperature regimes differing by 5 °C for three months. We found that the abundance and composition of ant-associated bacteria were sensitive to elevated temperatures in both field and laboratory experiments. We observed a subset of taxa that responded similarly to temperature in the experimental and observational study, suggesting a role of seasonal temperature and local temperature differences amongst nests in shaping microbiomes within the ant population. Bacterial mutualists in the genus Cephaloticoccus (Opitutales: Opitutaceae) were especially sensitive to change in temperature-decreasing in abundance in naturally warm summer nests and warm growth chambers. We also report the discovery of a member of the Candidate Phlya Radiation (Phylum: Gracilibacteria), a suspected epibiont, found in low abundance within the guts of this ant species.
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Affiliation(s)
- Marshall S McMunn
- Department of Environmental Studies, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, USA.,Department of Entomology and Nematology, University of California, Davis, One Shields Avenue, Davis, California 95616, USA
| | - Asher I Hudson
- Center for Population Biology, Department of Evolution and Ecology, University of California, Davis, One Shields Avenue, Davis, California 95616, USA
| | - Ash T Zemenick
- Department of Entomology and Nematology, University of California, Davis, One Shields Avenue, Davis, California 95616, USA.,Sagehen Creek Field Station, University of California Berkeley, 11616 Sage Hen Rd, Truckee, CA, 96161, USA
| | - Monika Egerer
- Department of Environmental Studies, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, USA.,Technical University of Munich, TUM School of Life Sciences, Hans Carl-von-Carlowitz-Platz 2, 85354 Freising, Germany
| | - Lucas Bennett
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, One Shields Avenue, Davis, California 95616, USA
| | - Stacy M Philpott
- Department of Environmental Studies, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, USA
| | - Rachel L Vannette
- Department of Entomology and Nematology, University of California, Davis, One Shields Avenue, Davis, California 95616, USA
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20
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James EB, Pan X, Schwartz O, Wilson ACC. SymbiQuant: A Machine Learning Object Detection Tool for Polyploid Independent Estimates of Endosymbiont Population Size. Front Microbiol 2022; 13:816608. [PMID: 35663891 PMCID: PMC9160162 DOI: 10.3389/fmicb.2022.816608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 03/31/2022] [Indexed: 11/13/2022] Open
Abstract
Quantifying the size of endosymbiont populations is challenging because endosymbionts are typically difficult or impossible to culture and commonly polyploid. Current approaches to estimating endosymbiont population sizes include quantitative PCR (qPCR) targeting endosymbiont genomic DNA and flow-cytometry. While qPCR captures genome copy number data, it does not capture the number of bacterial cells in polyploid endosymbiont populations. In contrast, flow cytometry can capture accurate estimates of whole host-level endosymbiont population size, but it is not readily able to capture data at the level of endosymbiotic host cells. To complement these existing approaches for estimating endosymbiont population size, we designed and implemented an object detection/segmentation tool for counting the number of endosymbiont cells in micrographs of host tissues. The tool, called SymbiQuant, which makes use of recent advances in deep neural networks includes a graphic user interface that allows for human curation of tool output. We trained SymbiQuant for use in the model aphid/Buchnera endosymbiosis and studied Buchnera population dynamics and phenotype over aphid postembryonic development. We show that SymbiQuant returns accurate counts of endosymbionts, and readily captures Buchnera phenotype. By replacing our training data with data composed of annotated microscopy images from other models of endosymbiosis, SymbiQuant has the potential for broad application. Our tool, which is available on GitHub, adds to the repertoire of methods researchers can use to study endosymbiosis at the organismal, genome, and now endosymbiotic host tissue or cell levels.
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Affiliation(s)
- Edward B. James
- Department of Biology, University of Miami, Coral Gables, FL, United States
- *Correspondence: Edward B. James,
| | - Xu Pan
- Computational Neuroscience Lab, Department of Computer Science, University of Miami, Coral Gables, FL, United States
| | - Odelia Schwartz
- Computational Neuroscience Lab, Department of Computer Science, University of Miami, Coral Gables, FL, United States
| | - Alex C. C. Wilson
- Department of Biology, University of Miami, Coral Gables, FL, United States
- Alex C. C. Wilson,
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21
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Tougeron K, Iltis C. Impact of heat stress on the fitness outcomes of symbiotic infection in aphids: a meta-analysis. Proc Biol Sci 2022; 289:20212660. [PMID: 35350854 PMCID: PMC8965392 DOI: 10.1098/rspb.2021.2660] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Beneficial microorganisms shape the evolutionary trajectories of their hosts, facilitating or constraining the colonization of new ecological niches. One convincing example entails the responses of insect-microbe associations to rising temperatures. Indeed, insect resilience to stressful high temperatures depends on the genetic identity of the obligate symbiont and the presence of heat-protective facultative symbionts. As extensively studied organisms, aphids and their endosymbiotic bacteria represent valuable models to address eco-evolutionary questions about the thermal ecology of insect-microbe partnerships, with broad relevance to various biological systems and insect models. This meta-analysis aims to quantify the context-dependent impacts of symbionts on host phenotype in benign or stressful heat conditions, across fitness traits, types of heat stress and symbiont species. We found that warming lowered the benefits (resistance to parasitoids) and costs (development, fecundity) of infection by facultative symbionts, which was overall mostly beneficial to the hosts under short-term heat stress (heat shock) rather than extended warming. Heat-tolerant genotypes of the obligate symbiont Buchnera aphidicola and some facultative symbionts (Rickettsia sp., Serratia symbiotica) improved or maintained aphid fitness under heat stress. We discuss the implications of these findings for the general understanding of the cost-benefit balance of insect-microbe associations across multiple traits and their eco-evolutionary dynamics faced with climate change.
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Affiliation(s)
- Kévin Tougeron
- Earth and Life Institute, Ecology and Biodiversity, Université catholique de Louvain, Louvain-la-Neuve, Belgium,UMR CNRS 7058-EDYSAN, Université de Picardie Jules Verne, Amiens, France
| | - Corentin Iltis
- Earth and Life Institute, Ecology and Biodiversity, Université catholique de Louvain, Louvain-la-Neuve, Belgium
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22
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Sun J, Tan X, Li Q, Francis F, Chen J. Effects of Different Temperatures on the Development and Reproduction of Sitobion miscanthi From Six Different Regions in China. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.794495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The increase in temperature caused by global warming has greatly impacted plant growth and pest population dynamics worldwide, especially for wheat aphids. In this study, Sitobion miscanthi individuals from six geographic populations located in different wheat-producing areas in China were compared with regard to their growth, development, survival, and reproductive under different temperature conditions (17, 22 and 27°C). A population life-table analysis and a correlation analysis between geographic factors and S. miscanthi longevity or fecundity were also performed. Temperature significantly affected the nymphal development duration (NDD), the adult longevity (ALY) and the fecundity (AFY) of the aphids, however, latitude can only affect the NDD and ALY. There is an obvious interaction between temperature and latitude on the NDD, ALY, and AFY. The NDD in the three northern populations was significantly shorter than that in the southern populations. The ALY in northern populations was significantly longer than that in southern populations at different temperatures. Except for Yinchuan population was no significantly different under different degrees, the ALY of other populations was significantly shortened at 27°C. The AFY of northern populations was significantly lower than that of southern populations at 22°C, while significantly higher at 27°C. With the increase of temperature, the fecundity of northern population gradually decreased from 17 to 22°C, while the southern population suddenly decreased at 27°C. The curves of survival rate (sxj) in southern populations were significantly shorter than that of northern population. Especially the populations in Suzhou and Wuhan, in which the survival rate decreased rapidly at 27°C. Age-specific survival rate (lx) of southern populations began to decline rapidly on 15 days of age at 27°C, while those of northern populations were not significantly affected until on 20 days of age. The highest peaks of age-stage fecundity (fxj), age-specific fecundity (mx), and age-specific net maternity (lxmx) were occurred in northern populations. In addition, there was a positive correlation between latitude and longevity under the three degrees, however, only at 27°C, there was a positive correlation between latitude and fecundity. Our result proved that the higher reproductive rate of southern population requires aphids to live at the suitable ambient temperature, and aphid populations in the north have a wider ecological amplitude. The results will be helpful for predicting the potential aphid outbreaks in China’s main wheat areas under suitable conditions.
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23
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Yang K, Yuan MY, Liu Y, Guo CL, Liu TX, Zhang YJ, Chu D. First evidence for thermal tolerance benefits of the bacterial symbiont Cardinium in an invasive whitefly, Bemisia tabaci. PEST MANAGEMENT SCIENCE 2021; 77:5021-5031. [PMID: 34216527 DOI: 10.1002/ps.6543] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 07/03/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUD Cardinium symbiont is a maternally inherited bacterial endosymbiont and widely spreads in arthropods including Bemisia tabaci (Hemiptera: Aleyrodidae). However, the potential role of Cardinium played in the biology of their hosts is largely unknown. In two genetic lines (i.e. LS and SG lines) of B. tabaci MED, collected from different locations in China, we tested the effects of Cardinium on the performance of the host whitefly under a constant high temperature (31 °C) using the age-stage two-sex life table method, and explored the genes influenced by Cardinium-infection by RNA-sequencing. RESULTS We found that Cardinium did provide protection of B. tabaci against heat stress under 31 °C. However, there was a significant connection between Cardinium-infection and whitefly genetic backgrounds. Performance revealed that Cardinium infection can increase the longevity of both female and male adults and oviposition periods in both lines, but it also conferred benefits of fecundity and pre-adult period to LS line. Additionally, the population parameters such as intrinsic rate of increase (r), finite rate of increase (λ) and mean generation time (T) demonstrated that Cardinium infection conferred fitness benefits to LS line but not to SG line. Transcriptome analysis indicated that several genes related to homeostasis and metamorphosis such as ubiquitin-related genes were highly expressed in Cardinium-infected B. tabaci. CONCLUSION The research provided the first evidence that Cardinium can increase the thermal tolerance of whitefly, which may be associated with host genetic background.
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Affiliation(s)
- Kun Yang
- Key Lab of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
| | - Meng-Ying Yuan
- Key Lab of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
| | - Ying Liu
- Key Lab of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
| | - Chen-Liang Guo
- Key Lab of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
| | - Tong-Xian Liu
- Key Lab of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
| | - You-Jun Zhang
- Department of Plant Protection, Institute of Vegetables and Flowers, |Chinese Academy of Agricultural Sciences, Beijing, China
| | - Dong Chu
- Key Lab of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
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24
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Iltis C, Tougeron K, Hance T, Louâpre P, Foray V. A perspective on insect-microbe holobionts facing thermal fluctuations in a climate-change context. Environ Microbiol 2021; 24:18-29. [PMID: 34713541 DOI: 10.1111/1462-2920.15826] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 10/16/2021] [Accepted: 10/19/2021] [Indexed: 11/29/2022]
Abstract
Temperature influences the ecology and evolution of insects and their symbionts by impacting each partner independently and their interactions, considering the holobiont as a primary unit of selection. There are sound data about the responses of these partnerships to constant temperatures and sporadic thermal stress (mostly heat shock). However, the current understanding of the thermal ecology of insect-microbe holobionts remains patchy because the complex thermal fluctuations (at different spatial and temporal scales) experienced by these organisms in nature have often been overlooked experimentally. This may drastically constrain our ability to predict the fate of mutualistic interactions under climate change, which will alter both mean temperatures and thermal variability. Here, we tackle down these issues by focusing on the effects of temperature fluctuations on the evolutionary ecology of insect-microbe holobionts. We propose potentially worth-investigating research avenues to (i) evaluate the relevance of theoretical concepts used to predict the biological impacts of temperature fluctuations when applied to holobionts; (ii) acknowledge the plastic (behavioural thermoregulation, physiological acclimation) and genetic responses (evolution) expressed by holobionts in fluctuating thermal environments; and (iii) explore the potential impacts of previously unconsidered patterns of temperature fluctuations on the outcomes and the dynamic of these insect-microbe associations.
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Affiliation(s)
- Corentin Iltis
- Earth and Life Institute, Biodiversity Research Center, Université catholique de Louvain, Croix du Sud 4-5, Louvain-la-Neuve, 1348, Belgium
| | - Kévin Tougeron
- Earth and Life Institute, Biodiversity Research Center, Université catholique de Louvain, Croix du Sud 4-5, Louvain-la-Neuve, 1348, Belgium.,UMR CNRS 7058 EDYSAN (Ecologie et Dynamique des Systèmes Anthropisés), Université de Picardie Jules Verne, 33 rue St Leu, Amiens, 80039, France
| | - Thierry Hance
- Earth and Life Institute, Biodiversity Research Center, Université catholique de Louvain, Croix du Sud 4-5, Louvain-la-Neuve, 1348, Belgium
| | - Philippe Louâpre
- UMR CNRS 6282 Biogéosciences, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, Dijon, 21000, France
| | - Vincent Foray
- UMR CNRS 7261 Institut de Recherche sur la Biologie de l'Insecte, Université de Tours, Parc Grandmont, Tours, 37200, France
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25
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Fenton A, Camus MF, Hurst GDD. Positive selection on mitochondria may eliminate heritable microbes from arthropod populations. Proc Biol Sci 2021; 288:20211735. [PMID: 34583583 PMCID: PMC8488761 DOI: 10.1098/rspb.2021.1735] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Diverse eukaryotic taxa carry facultative heritable symbionts, microbes that are passed from mother to offspring. These symbionts are coinherited with mitochondria, and selection favouring either new symbionts, or new symbiont variants, is known to drive loss of mitochondrial diversity as a correlated response. More recently, evidence has accumulated of episodic directional selection on mitochondria, but with currently unknown consequences for symbiont evolution. We therefore employed a population genetic mean field framework to model the impact of selection on mitochondrial DNA (mtDNA) upon symbiont frequency for three generic scenarios of host–symbiont interaction. Our models predict that direct selection on mtDNA can drive symbionts out of the population where a positively selected mtDNA mutation occurs initially in an individual that is uninfected with the symbiont, and the symbiont is initially at low frequency. When, by contrast, the positively selected mtDNA mutation occurs in a symbiont-infected individual, the mutation becomes fixed and in doing so removes symbiont variation from the population. We conclude that the molecular evolution of symbionts and mitochondria, which has previously been viewed from a perspective of selection on symbionts driving the evolution of a neutral mtDNA marker, should be reappraised in the light of positive selection on mtDNA.
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Affiliation(s)
- Andy Fenton
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - M Florencia Camus
- Research Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Gregory D D Hurst
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
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Xu S, Chen J, Qin M, Jiang L, Qiao G. Geography-dependent symbiont communities in two oligophagous aphid species. FEMS Microbiol Ecol 2021; 97:6368335. [PMID: 34506623 PMCID: PMC8478477 DOI: 10.1093/femsec/fiab132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/08/2021] [Indexed: 01/07/2023] Open
Abstract
Aphids and their diverse symbionts have become a good model to study bacteria-arthropod symbiosis. The feeding habits of aphids are usually influenced by a variety of symbionts. Most studies on symbiont diversity have focused on polyphagous aphids, while symbiont community patterns for oligophagous aphids remain unclear. Here, we surveyed the bacterial communities in natural populations of two oligophagous aphids, Melanaphis sacchari and Neophyllaphis podocarpi, in natural populations. Seven common symbionts were detected, among which Buchnera aphidicola and Wolbachia were the most prevalent. In addition, an uncommon Sodalis-like symbiont was also detected in these two aphids, and Gilliamella was found in some samples of M. sacchari. We further assessed the significant variation in symbiont communities within the two aphid species, geographical regions and host specialization using statistical and ordination analyses. Geography was an important factor in shaping the symbiont community structure in these oligophagous aphids. Furthermore, the strong geographical influence may be related to specific environmental factors, especially temperature, among different regions. These findings extend our knowledge of the significance of geography and its associated environmental conditions in the symbiont community structure associated with oligophagous aphids.
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Affiliation(s)
- Shifen Xu
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Chen
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Man Qin
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liyun Jiang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Gexia Qiao
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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Carpenter M, Peng L, Smith AH, Joffe J, O’Connor M, Oliver KM, Russell JA. Frequent Drivers, Occasional Passengers: Signals of Symbiont-Driven Seasonal Adaptation and Hitchhiking in the Pea Aphid, Acyrthosiphon pisum. INSECTS 2021; 12:805. [PMID: 34564245 PMCID: PMC8466206 DOI: 10.3390/insects12090805] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 09/02/2021] [Accepted: 09/04/2021] [Indexed: 12/25/2022]
Abstract
Insects harbor a variety of maternally inherited bacterial symbionts. As such, variation in symbiont presence/absence, in the combinations of harbored symbionts, and in the genotypes of harbored symbiont species provide heritable genetic variation of potential use in the insects' adaptive repertoires. Understanding the natural importance of symbionts is challenging but studying their dynamics over time can help to elucidate the potential for such symbiont-driven insect adaptation. Toward this end, we studied the seasonal dynamics of six maternally transferred bacterial symbiont species in the multivoltine pea aphid (Acyrthosiphon pisum). Our sampling focused on six alfalfa fields in southeastern Pennsylvania, and spanned 14 timepoints within the 2012 growing season, in addition to two overwintering periods. To test and generate hypotheses on the natural relevance of these non-essential symbionts, we examined whether symbiont dynamics correlated with any of ten measured environmental variables from the 2012 growing season, including some of known importance in the lab. We found that five symbionts changed prevalence across one or both overwintering periods, and that the same five species underwent such frequency shifts across the 2012 growing season. Intriguingly, the frequencies of these dynamic symbionts showed robust correlations with a subset of our measured environmental variables. Several of these trends supported the natural relevance of lab-discovered symbiont roles, including anti-pathogen defense. For a seventh symbiont-Hamiltonella defensa-studied previously across the same study periods, we tested whether a reported correlation between prevalence and temperature stemmed not from thermally varying host-level fitness effects, but from selection on co-infecting symbionts or on aphid-encoded alleles associated with this bacterium. In general, such "hitchhiking" effects were not evident during times with strongly correlated Hamiltonella and temperature shifts. However, we did identify at least one time period in which Hamiltonella spread was likely driven by selection on a co-infecting symbiont-Rickettsiella viridis. Recognizing the broader potential for such hitchhiking, we explored selection on co-infecting symbionts as a possible driver behind the dynamics of the remaining six species. Out of twelve examined instances of symbiont dynamics unfolding across 2-week periods or overwintering spans, we found eight in which the focal symbiont underwent parallel frequency shifts under single infection and one or more co-infection contexts. This supported the idea that phenotypic variation created by the presence/absence of individual symbionts is a direct target for selection, and that symbiont effects can be robust under co-habitation with other symbionts. Contrastingly, in two cases, we found that selection may target phenotypes emerging from symbiont co-infections, with specific species combinations driving overall trends for the focal dynamic symbionts, without correlated change under single infection. Finally, in three cases-including the one described above for Hamiltonella-our data suggested that incidental co-infection with a (dis)favored symbiont could lead to large frequency shifts for "passenger" symbionts, conferring no apparent cost or benefit. Such hitchhiking has rarely been studied in heritable symbiont systems. We propose that it is more common than appreciated, given the widespread nature of maternally inherited bacteria, and the frequency of multi-species symbiotic communities across insects.
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Affiliation(s)
- Melissa Carpenter
- Department of Biodiversity, Earth, and Environmental Science, Drexel University, 3250 Chestnut St., Philadelphia, PA 19104, USA; (M.C.); (A.H.S.); (M.O.)
| | - Linyao Peng
- Department of Biology, Drexel University, 3245 Chestnut St., Philadelphia, PA 19104, USA; (L.P.); (J.J.)
| | - Andrew H. Smith
- Department of Biodiversity, Earth, and Environmental Science, Drexel University, 3250 Chestnut St., Philadelphia, PA 19104, USA; (M.C.); (A.H.S.); (M.O.)
- Department of Biology, Drexel University, 3245 Chestnut St., Philadelphia, PA 19104, USA; (L.P.); (J.J.)
| | - Jonah Joffe
- Department of Biology, Drexel University, 3245 Chestnut St., Philadelphia, PA 19104, USA; (L.P.); (J.J.)
| | - Michael O’Connor
- Department of Biodiversity, Earth, and Environmental Science, Drexel University, 3250 Chestnut St., Philadelphia, PA 19104, USA; (M.C.); (A.H.S.); (M.O.)
| | - Kerry M. Oliver
- Department of Entomology, University of Georgia, 120 Cedar St., Athens, GA 30602, USA;
| | - Jacob A. Russell
- Department of Biodiversity, Earth, and Environmental Science, Drexel University, 3250 Chestnut St., Philadelphia, PA 19104, USA; (M.C.); (A.H.S.); (M.O.)
- Department of Biology, Drexel University, 3245 Chestnut St., Philadelphia, PA 19104, USA; (L.P.); (J.J.)
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Fakhour S, Renoz F, Ambroise J, Pons I, Noël C, Gala JL, Hance T. Insight into the bacterial communities of the subterranean aphid Anoecia corni. PLoS One 2021; 16:e0256019. [PMID: 34379678 PMCID: PMC8357138 DOI: 10.1371/journal.pone.0256019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 07/28/2021] [Indexed: 11/23/2022] Open
Abstract
Many insect species are associated with bacterial partners that can significantly influence their evolutionary ecology. Compared to other insect groups, aphids harbor a bacterial microbiota that has the reputation of being poorly diversified, generally limited to the presence of the obligate nutritional symbiont Buchnera aphidicola and some facultative symbionts. In this study, we analyzed the bacterial diversity associated with the dogwood-grass aphid Anoecia corni, an aphid species that spends much of its life cycle in a subterranean environment. Little is known about the bacterial diversity associated with aphids displaying such a lifestyle, and one hypothesis is that close contact with the vast microbial community of the rhizosphere could promote the acquisition of a richer bacterial diversity compared to other aphid species. Using 16S rRNA amplicon Illumina sequencing on specimens collected on wheat roots in Morocco, we identified 10 bacterial operational taxonomic units (OTUs) corresponding to five bacterial genera. In addition to the obligate symbiont Buchnera, we identified the facultative symbionts Serratia symbiotica and Wolbachia in certain aphid colonies. The detection of Wolbachia is unexpected as it is considered rare in aphids. Moreover, its biological significance remains unknown in these insects. Besides, we also detected Arsenophonus and Dactylopiibacterium carminicum. These results suggest that, despite its subterranean lifestyle, A. corni shelter a bacterial diversity mainly limited to bacterial endosymbionts.
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Affiliation(s)
- Samir Fakhour
- Department of Plant Protection, National Institute for Agricultural Research (INRA), Béni-Mellal, Morocco
- Earth and Life Institute, UC Louvain, Louvain-la-Neuve, Belgium
| | - François Renoz
- Earth and Life Institute, UC Louvain, Louvain-la-Neuve, Belgium
| | - Jérôme Ambroise
- Center for Applied Molecular Technologies (CTMA), Institut de Recherche Expérimentale et Clinique (IREC), UC Louvain, Woluwe-Saint-Lambert, Belgium
| | - Inès Pons
- Earth and Life Institute, UC Louvain, Louvain-la-Neuve, Belgium
| | - Christine Noël
- Earth and Life Institute, UC Louvain, Louvain-la-Neuve, Belgium
| | - Jean-Luc Gala
- Center for Applied Molecular Technologies (CTMA), Institut de Recherche Expérimentale et Clinique (IREC), UC Louvain, Woluwe-Saint-Lambert, Belgium
| | - Thierry Hance
- Earth and Life Institute, UC Louvain, Louvain-la-Neuve, Belgium
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29
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Zhu YX, Song ZR, Zhang YY, Hoffmann AA, Hong XY. Spider Mites Singly Infected With Either Wolbachia or Spiroplasma Have Reduced Thermal Tolerance. Front Microbiol 2021; 12:706321. [PMID: 34305877 PMCID: PMC8292952 DOI: 10.3389/fmicb.2021.706321] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 06/14/2021] [Indexed: 02/01/2023] Open
Abstract
Heritable symbionts play an essential role in many aspects of host ecology in a temperature-dependent manner. However, how temperature impacts the host and their interaction with endosymbionts remains largely unknown. Here, we investigated the impact of moderate (20°C) and high (30 and 35°C) temperatures on symbioses between the spider mite Tetranychus truncatus and two maternally inherited endosymbionts (Wolbachia and Spiroplasma). We found that the thermal tolerance of mites (as measured by survival after heat exposure) was lower for mites that were singly infected with either Wolbachia or Spiroplasma than it was for co-infected or uninfected mites. Although a relatively high temperature (30°C) is thought to promote bacterial replication, rearing at high temperature (35°C) resulted in losses of Wolbachia and particularly Spiroplasma. Exposing the mites to 20°C reduced the density and transmission of Spiroplasma but not Wolbachia. The four spider mite strains tested differed in the numbers of heat shock genes (Hsps) induced under moderate or high temperature exposure. In thermal preference (Tp) assays, the two Wolbachia-infected spider mite strains preferred a lower temperature than strains without Wolbachia. Our results show that endosymbiont-mediated spider mite responses to temperature stress are complex, involving a combination of changing endosymbiont infection patterns, altered thermoregulatory behavior, and transcription responses.
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Affiliation(s)
- Yu-Xi Zhu
- Department of Entomology, Nanjing Agricultural University, Nanjing, China.,Institute of Applied Entomology, School of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Zhang-Rong Song
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
| | - Yi-Yin Zhang
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
| | - Ary A Hoffmann
- School of BioSciences, Bio21 Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Xiao-Yue Hong
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
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30
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Six DL, Klepzig KD. Context Dependency in Bark Beetle-Fungus Mutualisms Revisited: Assessing Potential Shifts in Interaction Outcomes Against Varied Genetic, Ecological, and Evolutionary Backgrounds. Front Microbiol 2021; 12:682187. [PMID: 34054789 PMCID: PMC8149605 DOI: 10.3389/fmicb.2021.682187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 04/19/2021] [Indexed: 11/13/2022] Open
Abstract
Context dependency occurs when biological interactions shift in sign or magnitude depending upon genetic, abiotic, and biotic context. Most models of mutualism address systems where interaction outcomes slide along a mutualism-antagonism continuum as environmental conditions vary altering cost-benefit relationships. However, these models do not apply to the many mutualisms that involve by-product benefits and others that do not have antagonistic alternate states. The ubiquity of such mutualisms indicates a need for different approaches and models to understand how environmental variability influences their strength, stability, and ecological roles. In this paper, we apply the concept of context dependency to mutualisms among bark beetles and fungi that span a variety of life strategies and exposures to environmental variability. Bark beetles and their mutualist fungi co-construct a niche based on by-product benefits that allows them to exist in a resource that is otherwise intractable or inaccessible. For the closest of these partnerships, this has resulted in some of the most influential agents of forest mortality in conifer forests worldwide. Understanding these symbioses is key to understanding their influence on forest structure and dynamics and responses to change. We found no evidence that bark beetle mutualisms change in sign as conditions vary, only in magnitude, and that the "closest" (and most environmentally influential) of these partnerships have evolved behaviors and mechanisms to reduce context-dependency and stabilize benefit delivery. The bark beetle-fungus symbioses most likely to slide along a mutualism-antagonism continuum are those involving loosely associated facultative symbionts that may provide benefits under some circumstances and that are horizontally transmitted by the beetle host. Additionally, some symbiotic fungi are never mutualists - these "third party" fungi are exploiters and may shift from commensalism to antagonism depending on environmental context. Our assessment indicates that a careful differentiation between bark beetle-fungus partnerships is crucial to understanding how they influence forests and respond to environmental variability.
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Affiliation(s)
- Diana L Six
- Department of Ecosystem and Conservation Science, The University of Montana, Missoula, MT, United States
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31
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Smith AH, O'Connor MP, Deal B, Kotzer C, Lee A, Wagner B, Joffe J, Woloszynek S, Oliver KM, Russell JA. Does getting defensive get you anywhere?-Seasonal balancing selection, temperature, and parasitoids shape real-world, protective endosymbiont dynamics in the pea aphid. Mol Ecol 2021; 30:2449-2472. [PMID: 33876478 DOI: 10.1111/mec.15906] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/16/2021] [Accepted: 03/25/2021] [Indexed: 12/11/2022]
Abstract
Facultative, heritable endosymbionts are found at intermediate prevalence within most insect species, playing frequent roles in their hosts' defence against environmental pressures. Focusing on Hamiltonella defensa, a common bacterial endosymbiont of aphids, we tested the hypothesis that such pressures impose seasonal balancing selection, shaping a widespread infection polymorphism. In our studied pea aphid (Acyrthosiphon pisum) population, Hamiltonella frequencies ranged from 23.2% to 68.1% across a six-month longitudinal survey. Rapid spikes and declines were often consistent across fields, and we estimated that selection coefficients for Hamiltonella-infected aphids changed sign within this field season. Prior laboratory research suggested antiparasitoid defence as the major Hamiltonella benefit, and costs under parasitoid absence. While a prior field study suggested these forces can sometimes act as counter-weights in a regime of seasonal balancing selection, our present survey showed no significant relationship between parasitoid wasps and Hamiltonella prevalence. Field cage experiments provided some explanation: parasitoids drove modest ~10% boosts to Hamiltonella frequencies that would be hard to detect under less controlled conditions. They also showed that Hamiltonella was not always costly under parasitoid exclusion, contradicting another prediction. Instead, our longitudinal survey - and two overwintering studies - showed temperature to be the strongest predictor of Hamiltonella prevalence. Matching some prior lab discoveries, this suggested that thermally sensitive costs and benefits, unrelated to parasitism, can shape Hamiltonella dynamics. These results add to a growing body of evidence for rapid, seasonal adaptation in multivoltine organisms, suggesting that such adaptation can be mediated through the diverse impacts of heritable bacterial endosymbionts.
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Affiliation(s)
- Andrew H Smith
- Department of Biology, Drexel University, Philadelphia, PA, USA
| | - Michael P O'Connor
- Department of Biodiversity, Earth, and Environmental Science, Drexel University, Philadelphia, PA, USA
| | - Brooke Deal
- Department of Biology, Drexel University, Philadelphia, PA, USA
| | - Coleman Kotzer
- Department of Biology, Drexel University, Philadelphia, PA, USA
| | - Amanda Lee
- Department of Biology, Drexel University, Philadelphia, PA, USA
| | - Barrett Wagner
- Department of Biology, Drexel University, Philadelphia, PA, USA
| | - Jonah Joffe
- Department of Biology, Drexel University, Philadelphia, PA, USA
| | | | - Kerry M Oliver
- Department of Entomology, University of Georgia, Athens, GA, USA
| | - Jacob A Russell
- Department of Biology, Drexel University, Philadelphia, PA, USA
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Effect of the Genotypic Variation of an Aphid Host on the Endosymbiont Associations in Natural Host Populations. INSECTS 2021; 12:insects12030217. [PMID: 33806260 PMCID: PMC8001399 DOI: 10.3390/insects12030217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 02/10/2021] [Accepted: 02/10/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary The host–endosymbiont complex could be a key determinant in spread and maintenance of the infection polymorphism of endosymbionts. Variation among host–endosymbiont complexes can contribute to genetic variation of a host species and then provide the necessary material for the operating coevolutionary dynamics. We studied the seasonal dynamic of facultative endosymbiont infections among different host clones of the grain aphid Sitobion avenae and whether their presence affects the total hymenopteran parasitism of aphid hosts at the field level. We observed that aphid infections in the field with endosymbionts increase over time, by favoring particular aphid clones closely associated with endosymbionts, but without an effect of endosymbionts on parasitism rate in the host populations. Our results highlight the importance of host–endosymbiont couples in shaping the prevalence and distributions of symbionts throughout nature and the success of their hosts as pests. Abstract Understanding the role of facultative endosymbionts on the host’s ecology has been the main aim of the research in symbiont–host systems. However, current research on host–endosymbiont dynamics has failed to examine the genetic background of the hosts and its effect on host–endosymbiont associations in real populations. We have addressed the seasonal dynamic of facultative endosymbiont infections among different host clones of the grain aphid Sitobion avenae, on two cereal crops (wheat and oat) and whether their presence affects the total hymenopteran parasitism of aphid hosts at the field level. We present evidence of rapid seasonal shifts in the endosymbiont frequency, suggesting a positive selection of endosymbionts at the host-level (aphids) through an agricultural growing season, by two mechanisms; (1) an increase of aphid infections with endosymbionts over time, and (2) the seasonal replacement of host clones within natural populations by increasing the prevalence of aphid clones closely associated to endosymbionts. Our results highlight how genotypic variation of hosts can affect the endosymbiont prevalence in the field, being an important factor for understanding the magnitude and direction of the adaptive and/or maladaptive responses of hosts to the environment.
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Monticelli LS, Bishop J, Desneux N, Gurr GM, Jaworski CC, McLean AH, Thomine E, Vanbergen AJ. Multiple global change impacts on parasitism and biocontrol services in future agricultural landscapes. ADV ECOL RES 2021. [DOI: 10.1016/bs.aecr.2021.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Gupta A, Nair S. Dynamics of Insect-Microbiome Interaction Influence Host and Microbial Symbiont. Front Microbiol 2020; 11:1357. [PMID: 32676060 PMCID: PMC7333248 DOI: 10.3389/fmicb.2020.01357] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 05/27/2020] [Indexed: 12/21/2022] Open
Abstract
Insects share an intimate relationship with their gut microflora and this symbiotic association has developed into an essential evolutionary outcome intended for their survival through extreme environmental conditions. While it has been clearly established that insects, with very few exceptions, associate with several microbes during their life cycle, information regarding several aspects of these associations is yet to be fully unraveled. Acquisition of bacteria by insects marks the onset of microbial symbiosis, which is followed by the adaptation of these bacterial species to the gut environment for prolonged sustenance and successful transmission across generations. Although several insect-microbiome associations have been reported and each with their distinctive features, diversifications and specializations, it is still unclear as to what led to these diversifications. Recent studies have indicated the involvement of various evolutionary processes operating within an insect body that govern the transition of a free-living microbe to an obligate or facultative symbiont and eventually leading to the establishment and diversification of these symbiotic relationships. Data from various studies, summarized in this review, indicate that the symbiotic partners, i.e., the bacteria and the insect undergo several genetic, biochemical and physiological changes that have profound influence on their life cycle and biology. An interesting outcome of the insect-microbe interaction is the compliance of the microbial partner to its eventual genome reduction. Endosymbionts possess a smaller genome as compared to their free-living forms, and thus raising the question what is leading to reductive evolution in the microbial partner. This review attempts to highlight the fate of microbes within an insect body and its implications for both the bacteria and its insect host. While discussion on each specific association would be too voluminous and outside the scope of this review, we present an overview of some recent studies that contribute to a better understanding of the evolutionary trajectory and dynamics of the insect-microbe association and speculate that, in the future, a better understanding of the nature of this interaction could pave the path to a sustainable and environmentally safe way for controlling economically important pests of crop plants.
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Affiliation(s)
| | - Suresh Nair
- Plant-Insect Interaction Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
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