1
|
Feng H, Wilson ACC. Experimental uncoupling of hosts and endosymbionts. mBio 2024; 15:e0111624. [PMID: 39028184 PMCID: PMC11323540 DOI: 10.1128/mbio.01116-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2024] Open
Abstract
Many organisms harbor heritable bacterial symbionts that offer context-specific benefits to their hosts. In some of these symbioses, symbionts live inside host cells as endosymbionts. Studying the biology of endosymbiosis is challenging because it is hard to independently cultivate hosts and endosymbionts. A recent study, using a simple defined growth medium at ambient temperature, established an axenic culture of the pea aphid's heritable bacterial endosymbiont, Candidatus Fukatsuia symbiotica (G. P. Maeda, M. K. Kelly, A. Sundar, and N. A. Moran, mBio 15:e03253-23, 2024, https://doi.org/10.1128/mbio.03253-23). Notably, the monoculture was capable of host recolonization, was stably transmitted, and returned similar host phenotypes to those observed in native infections. This advance in uncoupling the cultivation of an endosymbiont and its host opens avenues for genetic manipulation of the endosymbiont that will facilitate hypothesis-driven work to explore the mechanisms of host-endosymbiont biology and potentially facilitate the development of symbiont-mediated practical-application biotechnologies.
Collapse
Affiliation(s)
- Honglin Feng
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, Louisiana, USA
| | - Alex C. C. Wilson
- Department of Biology, University of Miami, Coral Gables, Florida, USA
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Macpherson CV, Daisley BA, Mallory E, Allen-Vercoe E. The untapped potential of cell culture in disentangling insect-microbial relationships. MICROBIOME RESEARCH REPORTS 2024; 3:20. [PMID: 38841412 PMCID: PMC11149091 DOI: 10.20517/mrr.2023.66] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 01/27/2024] [Accepted: 02/22/2024] [Indexed: 06/07/2024]
Abstract
Cell culture is a powerful technique for the investigation of molecular mechanisms fundamental to health and disease in a diverse array of organisms. Cell lines offer several advantages, namely their simplistic approach and high degree of reproducibility. One field where cell culture has proven particularly useful is the study of the microbiome, where cell culture has led to the illumination of microbial influences on host immunity, nutrition, and physiology. Thus far, researchers have focused cell culture work predominantly on humans, but the growing field of insect microbiome research stands to benefit greatly from its application. Insects constitute one of Earth's most diverse and ancient life forms and, just as with humans, possess microbiomes with great significance to their health. Insects, which play critical roles in supporting food security and ecological stability, are facing increasing threats from agricultural intensification, climate change, and pesticide use. As the microbiome is closely tied to host health, gaining a more robust understanding is of increasing importance. In this review, we assert that the cultivation and utilization of insect gut cell lines in microbiome research will bridge critical knowledge gaps essential for informing insect management practices in a world under pressure.
Collapse
Affiliation(s)
| | | | | | - Emma Allen-Vercoe
- Department of Molecular and Cellular Biology, University of Guelph, Guelph N1G 2W1, ON, Canada
| |
Collapse
|
4
|
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.
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Peng L, Hoban J, Joffe J, Smith AH, Carpenter M, Marcelis T, Patel V, Lynn-Bell N, Oliver KM, Russell JA. Cryptic community structure and metabolic interactions among the heritable facultative symbionts of the pea aphid. J Evol Biol 2023; 36:1712-1730. [PMID: 37702036 DOI: 10.1111/jeb.14216] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 06/07/2023] [Accepted: 07/18/2023] [Indexed: 09/14/2023]
Abstract
Most insects harbour influential, yet non-essential heritable microbes in their hemocoel. Communities of these symbionts exhibit low diversity. But their frequent multi-species nature raises intriguing questions on roles for symbiont-symbiont synergies in host adaptation, and on the stability of the symbiont communities, themselves. In this study, we build on knowledge of species-defined symbiont community structure across US populations of the pea aphid, Acyrthosiphon pisum. Through extensive symbiont genotyping, we show that pea aphids' microbiomes can be more precisely defined at the symbiont strain level, with strain variability shaping five out of nine previously reported co-infection trends. Field data provide a mixture of evidence for synergistic fitness effects and symbiont hitchhiking, revealing causes and consequences of these co-infection trends. To test whether within-host metabolic interactions predict common versus rare strain-defined communities, we leveraged the high relatedness of our dominant, community-defined symbiont strains vs. 12 pea aphid-derived Gammaproteobacteria with sequenced genomes. Genomic inference, using metabolic complementarity indices, revealed high potential for cooperation among one pair of symbionts-Serratia symbiotica and Rickettsiella viridis. Applying the expansion network algorithm, through additional use of pea aphid and obligate Buchnera symbiont genomes, Serratia and Rickettsiella emerged as the only symbiont community requiring both parties to expand holobiont metabolism. Through their joint expansion of the biotin biosynthesis pathway, these symbionts may span missing gaps, creating a multi-party mutualism within their nutrient-limited, phloem-feeding hosts. Recent, complementary gene inactivation, within the biotin pathways of Serratia and Rickettsiella, raises further questions on the origins of mutualisms and host-symbiont interdependencies.
Collapse
Affiliation(s)
- Linyao Peng
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, USA
| | - Jessica Hoban
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, USA
| | - Jonah Joffe
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, USA
| | - Andrew H Smith
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, USA
| | - Melissa Carpenter
- Department of Biodiversity, Earth, and Environmental Science, Drexel University, Philadelphia, Pennsylvania, USA
| | - Tracy Marcelis
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, USA
| | - Vilas Patel
- Department of Entomology, University of Georgia, Athens, Georgia, USA
| | - Nicole Lynn-Bell
- Department of Entomology, University of Georgia, Athens, Georgia, USA
| | - Kerry M Oliver
- Department of Entomology, University of Georgia, Athens, Georgia, USA
| | - Jacob A Russell
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, USA
| |
Collapse
|
7
|
Sun Y, Wang M, Cao L, Seim I, Zhou L, Chen J, Wang H, Zhong Z, Chen H, Fu L, Li M, Li C, Sun S. Mosaic environment-driven evolution of the deep-sea mussel Gigantidas platifrons bacterial endosymbiont. MICROBIOME 2023; 11:253. [PMID: 37974296 PMCID: PMC10652631 DOI: 10.1186/s40168-023-01695-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 10/11/2023] [Indexed: 11/19/2023]
Abstract
BACKGROUND The within-species diversity of symbiotic bacteria represents an important genetic resource for their environmental adaptation, especially for horizontally transmitted endosymbionts. Although strain-level intraspecies variation has recently been detected in many deep-sea endosymbionts, their ecological role in environmental adaptation, their genome evolution pattern under heterogeneous geochemical environments, and the underlying molecular forces remain unclear. RESULTS Here, we conducted a fine-scale metagenomic analysis of the deep-sea mussel Gigantidas platifrons bacterial endosymbiont collected from distinct habitats: hydrothermal vent and methane seep. Endosymbiont genomes were assembled using a pipeline that distinguishes within-species variation and revealed highly heterogeneous compositions in mussels from different habitats. Phylogenetic analysis separated the assemblies into three distinct environment-linked clades. Their functional differentiation follows a mosaic evolutionary pattern. Core genes, essential for central metabolic function and symbiosis, were conserved across all clades. Clade-specific genes associated with heavy metal resistance, pH homeostasis, and nitrate utilization exhibited signals of accelerated evolution. Notably, transposable elements and plasmids contributed to the genetic reshuffling of the symbiont genomes and likely accelerated adaptive evolution through pseudogenization and the introduction of new genes. CONCLUSIONS The current study uncovers the environment-driven evolution of deep-sea symbionts mediated by mobile genetic elements. Its findings highlight a potentially common and critical role of within-species diversity in animal-microbiome symbioses. Video Abstract.
Collapse
Affiliation(s)
- Yan Sun
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, and Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, 266237, China
| | - Minxiao Wang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, and Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, 266237, China
| | - Lei Cao
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, and Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, 266237, China
| | - Inge Seim
- Integrative Biology Laboratory, College of Life Sciences, Nanjing Normal University, Nanjing, 210046, China
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Li Zhou
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, and Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, 266237, China
| | - Jianwei Chen
- BGI Research-Qingdao, BGI, Qingdao, 266555, China
| | - Hao Wang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, and Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, 266237, China
| | - Zhaoshan Zhong
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, and Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, 266237, China
| | - Hao Chen
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, and Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, 266237, China
| | - Lulu Fu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, and Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, 266237, China
| | - Mengna Li
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, and Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, 266237, China
| | - Chaolun Li
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, and Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, 266237, China.
- South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Song Sun
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, and Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, 266237, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| |
Collapse
|
8
|
Higashi CHV, Nichols WL, Chevignon G, Patel V, Allison SE, Kim KL, Strand MR, Oliver KM. An aphid symbiont confers protection against a specialized RNA virus, another increases vulnerability to the same pathogen. Mol Ecol 2023; 32:936-950. [PMID: 36458425 PMCID: PMC10107813 DOI: 10.1111/mec.16801] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/24/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022]
Abstract
Insects often harbour heritable symbionts that provide defence against specialized natural enemies, yet little is known about symbiont protection when hosts face simultaneous threats. In pea aphids (Acyrthosiphon pisum), the facultative endosymbiont Hamiltonella defensa confers protection against the parasitoid, Aphidius ervi, and Regiella insecticola protects against aphid-specific fungal pathogens, including Pandora neoaphidis. Here, we investigated whether these two common aphid symbionts protect against a specialized virus A. pisum virus (APV), and whether their antifungal and antiparasitoid services are impacted by APV infection. We found that APV imposed large fitness costs on symbiont-free aphids and these costs were elevated in aphids also housing H. defensa. In contrast, APV titres were significantly reduced and costs to APV infection were largely eliminated in aphids with R. insecticola. To our knowledge, R. insecticola is the first aphid symbiont shown to protect against a viral pathogen, and only the second arthropod symbiont reported to do so. In contrast, APV infection did not impact the protective services of either R. insecticola or H. defensa. To better understand APV biology, we produced five genomes and examined transmission routes. We found that moderate rates of vertical transmission, combined with horizontal transfer through food plants, were the major route of APV spread, although lateral transfer by parasitoids also occurred. Transmission was unaffected by facultative symbionts. In summary, the presence and species identity of facultative symbionts resulted in highly divergent outcomes for aphids infected with APV, while not impacting defensive services that target other enemies. These findings add to the diverse phenotypes conferred by aphid symbionts, and to the growing body of work highlighting extensive variation in symbiont-mediated interactions.
Collapse
Affiliation(s)
| | - William L Nichols
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| | - Germain Chevignon
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| | - Vilas Patel
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| | - Suzanne E Allison
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| | - Kyungsun Lee Kim
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| | - Michael R Strand
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| | - Kerry M Oliver
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| |
Collapse
|
9
|
Villarroel CA, González-González A, Alvarez-Baca JK, Villarreal P, Ballesteros GI, Figueroa CC, Cubillos FA, Ramírez CC. Genome sequencing of a predominant clonal lineage of the grain aphid Sitobion avenae. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2022; 143:103742. [PMID: 35183733 DOI: 10.1016/j.ibmb.2022.103742] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 02/15/2022] [Accepted: 02/15/2022] [Indexed: 06/14/2023]
Abstract
The English grain aphid, Sitobion avenae, is a cosmopolitan pest that feeds on cereals, provoking substantial yield losses by injuring plant tissue and by vectoring plant viruses. Here we report a highly complete, de novo draft genome of the grain aphid using long-read sequencing. We generated an assembly of 2740 contigs with a N50 of 450 kb. We compared this draft genome with that of other aphid species, inspecting gene family evolution, genome-wide positive selection, and searched for horizontal gene transfer events. In addition, we described a recent copy number variant expansion of gene families involving aconitase, ABC transporter, and esterase genes that could be associated with resistance to insecticides and plant chemical defenses. This S. avenae genome obtained from a predominant invasive genotype can provide a framework for studying the spatial-temporal success of these clonal lineages in invaded agroecosystems.
Collapse
Affiliation(s)
- Carlos A Villarroel
- Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile; Instituto de Investigación Interdisciplinaria (I3), Universidad de Talca, Talca, Chile; Millennium Institute for Integrative Biology (iBio), Santiago, Chile.
| | | | | | - Pablo Villarreal
- Millennium Institute for Integrative Biology (iBio), Santiago, Chile; Universidad de Santiago de Chile, Facultad de Química y Biología, Departamento de Biología, Santiago, Chile
| | - Gabriel I Ballesteros
- Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile; Instituto de Investigación Interdisciplinaria (I3), Universidad de Talca, Talca, Chile
| | - Christian C Figueroa
- Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile; Centro de Ecología Molecular y Funcional, Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile
| | - Francisco A Cubillos
- Millennium Institute for Integrative Biology (iBio), Santiago, Chile; Universidad de Santiago de Chile, Facultad de Química y Biología, Departamento de Biología, Santiago, Chile
| | - Claudio C Ramírez
- Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile; Centro de Ecología Molecular y Funcional, Instituto de Ciencias Biológicas, Universidad de Talca, Talca, Chile
| |
Collapse
|
10
|
Prigot-Maurice C, Beltran-Bech S, Braquart-Varnier C. Why and how do protective symbionts impact immune priming with pathogens in invertebrates? DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2022; 126:104245. [PMID: 34453995 DOI: 10.1016/j.dci.2021.104245] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 07/29/2021] [Accepted: 08/24/2021] [Indexed: 06/13/2023]
Abstract
Growing evidence demonstrates that invertebrates display adaptive-like immune abilities, commonly known as "immune priming". Immune priming is a process by which a host improves its immune defences following an initial pathogenic exposure, leading to better protection after a subsequent infection with the same - or different - pathogens. Nevertheless, beneficial symbionts can enhance similar immune priming processes in hosts, such as when they face repeated infections with pathogens. This "symbiotic immune priming" protects the host against pathogenic viruses, bacteria, fungi, or eukaryotic parasites. In this review, we explore the extent to which protective symbionts interfere and impact immune priming against pathogens from both a mechanical (proximal) and an evolutionary (ultimate) point of view. We highlight that the immune priming of invertebrates is the cornerstone of the tripartite interaction of hosts/symbionts/pathogens. The main shared mechanism of immune priming (induced by symbionts or pathogens) is the sustained immune response at the beginning of host-microbial interactions. However, the evolutionary outcome of immune priming leads to a specific discrimination, which provides enhanced tolerance or resistance depending on the type of microbe. Based on several studies testing immune priming against pathogens in the presence or absence of protective symbionts, we observed that both types of immune priming could overlap and affect each other inside the same hosts. As protective symbionts could be an evolutionary force that influences immune priming, they may help us to better understand the heterogeneity of pathogenic immune priming across invertebrate populations and species.
Collapse
Affiliation(s)
- Cybèle Prigot-Maurice
- Université de Poitiers - UFR Sciences Fondamentales et Appliquées, Laboratoire Écologie et Biologie des Interactions - UMR CNRS 7267, Bâtiment B8-B35, 5 rue Albert Turpin, TSA 51106, F, 86073, POITIERS Cedex 9, France.
| | - Sophie Beltran-Bech
- Université de Poitiers - UFR Sciences Fondamentales et Appliquées, Laboratoire Écologie et Biologie des Interactions - UMR CNRS 7267, Bâtiment B8-B35, 5 rue Albert Turpin, TSA 51106, F, 86073, POITIERS Cedex 9, France
| | - Christine Braquart-Varnier
- Université de Poitiers - UFR Sciences Fondamentales et Appliquées, Laboratoire Écologie et Biologie des Interactions - UMR CNRS 7267, Bâtiment B8-B35, 5 rue Albert Turpin, TSA 51106, F, 86073, POITIERS Cedex 9, France
| |
Collapse
|
11
|
Boyd BM, Chevignon G, Patel V, Oliver KM, Strand MR. Evolutionary genomics of APSE: a tailed phage that lysogenically converts the bacterium Hamiltonella defensa into a heritable protective symbiont of aphids. Virol J 2021; 18:219. [PMID: 34758862 PMCID: PMC8579659 DOI: 10.1186/s12985-021-01685-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 11/01/2021] [Indexed: 12/12/2022] Open
Abstract
Background Most phages infect free-living bacteria but a few have been identified that infect heritable symbionts of insects or other eukaryotes. Heritable symbionts are usually specialized and isolated from other bacteria with little known about the origins of associated phages. Hamiltonella defensa is a heritable bacterial symbiont of aphids that is usually infected by a tailed, double-stranded DNA phage named APSE. Methods We conducted comparative genomic and phylogenetic studies to determine how APSE is related to other phages and prophages. Results Each APSE genome was organized into four modules and two predicted functional units. Gene content and order were near-fully conserved in modules 1 and 2, which encode predicted DNA metabolism genes, and module 4, which encodes predicted virion assembly genes. Gene content of module 3, which contains predicted toxin, holin and lysozyme genes differed among haplotypes. Comparisons to other sequenced phages suggested APSE genomes are mosaics with modules 1 and 2 sharing similarities with Bordetella-Bcep-Xylostella fastidiosa-like podoviruses, module 4 sharing similarities with P22-like podoviruses, and module 3 sharing no similarities with known phages. Comparisons to other sequenced bacterial genomes identified APSE-like elements in other heritable insect symbionts (Arsenophonus spp.) and enteric bacteria in the family Morganellaceae. Conclusions APSEs are most closely related to phage elements in the genus Arsenophonus and other bacteria in the Morganellaceae. Supplementary Information The online version contains supplementary material available at 10.1186/s12985-021-01685-y.
Collapse
Affiliation(s)
- Bret M Boyd
- Department of Entomology, University of Georgia Athens, Athens, GA, USA. .,Center for Biological Data Science, Virginia Commonwealth University, Richmond, VA, USA.
| | - Germain Chevignon
- Laboratoire de Génétique et Pathologie des Mollusques Marins, IFREMER, La Tremblade, France
| | - Vilas Patel
- Department of Entomology, University of Georgia Athens, Athens, GA, USA
| | - Kerry M Oliver
- Department of Entomology, University of Georgia Athens, Athens, GA, USA
| | - Michael R Strand
- Department of Entomology, University of Georgia Athens, Athens, GA, USA.
| |
Collapse
|
12
|
Smee MR, Raines SA, Ferrari J. Genetic identity and genotype × genotype interactions between symbionts outweigh species level effects in an insect microbiome. THE ISME JOURNAL 2021; 15:2537-2546. [PMID: 33712703 PMCID: PMC8397793 DOI: 10.1038/s41396-021-00943-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 02/10/2021] [Accepted: 02/18/2021] [Indexed: 02/07/2023]
Abstract
Microbial symbionts often alter the phenotype of their host. Benefits and costs to hosts depend on many factors, including host genotype, symbiont species and genotype, and environmental conditions. Here, we present a study demonstrating genotype-by-genotype (G×G) interactions between multiple species of endosymbionts harboured by an insect, and the first to quantify the relative importance of G×G interactions compared with species interactions in such systems. In the most extensive study to date, we microinjected all possible combinations of five Hamiltonella defensa and five Fukatsuia symbiotica (X-type; PAXS) isolates into the pea aphid, Acyrthosiphon pisum. We applied several ecological challenges: a parasitoid wasp, a fungal pathogen, heat shock, and performance on different host plants. Surprisingly, genetic identity and genotype × genotype interactions explained far more of the phenotypic variation (on average 22% and 31% respectively) than species identity or species interactions (on average 12% and 0.4%, respectively). We determined the costs and benefits associated with co-infection, and how these compared to corresponding single infections. All phenotypes were highly reliant on individual isolates or interactions between isolates of the co-infecting partners. Our findings highlight the importance of exploring the eco-evolutionary consequences of these highly specific interactions in communities of co-inherited species.
Collapse
Affiliation(s)
- Melanie R. Smee
- grid.5685.e0000 0004 1936 9668Department of Biology, University of York, York, UK ,grid.5386.8000000041936877XPresent Address: Microbiology Department, Cornell University, Ithaca, NY USA
| | - Sally A. Raines
- grid.5685.e0000 0004 1936 9668Department of Biology, University of York, York, UK
| | - Julia Ferrari
- grid.5685.e0000 0004 1936 9668Department of Biology, University of York, York, UK
| |
Collapse
|
13
|
Perreau J, Moran NA. Genetic innovations in animal-microbe symbioses. Nat Rev Genet 2021; 23:23-39. [PMID: 34389828 DOI: 10.1038/s41576-021-00395-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/28/2021] [Indexed: 02/07/2023]
Abstract
Animal hosts have initiated myriad symbiotic associations with microorganisms and often have maintained these symbioses for millions of years, spanning drastic changes in ecological conditions and lifestyles. The establishment and persistence of these relationships require genetic innovations on the parts of both symbionts and hosts. The nature of symbiont innovations depends on their genetic population structure, categorized here as open, closed or mixed. These categories reflect modes of inter-host transmission that result in distinct genomic features, or genomic syndromes, in symbionts. Although less studied, hosts also innovate in order to preserve and control symbiotic partnerships. New capabilities to sequence host-associated microbial communities and to experimentally manipulate both hosts and symbionts are providing unprecedented insights into how genetic innovations arise under different symbiont population structures and how these innovations function to support symbiotic relationships.
Collapse
Affiliation(s)
- Julie Perreau
- 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.
| |
Collapse
|
14
|
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.
Collapse
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
| |
Collapse
|
15
|
Kaech H, Dennis AB, Vorburger C. Triple RNA-Seq characterizes aphid gene expression in response to infection with unequally virulent strains of the endosymbiont Hamiltonella defensa. BMC Genomics 2021; 22:449. [PMID: 34134631 PMCID: PMC8207614 DOI: 10.1186/s12864-021-07742-8] [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: 02/01/2021] [Accepted: 05/20/2021] [Indexed: 11/10/2022] Open
Abstract
Background Secondary endosymbionts of aphids provide benefits to their hosts, but also impose costs such as reduced lifespan and reproductive output. The aphid Aphis fabae is host to different strains of the secondary endosymbiont Hamiltonella defensa, which encode different putative toxins. These strains have very different phenotypes: They reach different densities in the host, and the costs and benefits (protection against parasitoid wasps) they confer to the host vary strongly. Results We used RNA-Seq to generate hypotheses on why four of these strains inflict such different costs to A. fabae. We found different H. defensa strains to cause strain-specific changes in aphid gene expression, but little effect of H. defensa on gene expression of the primary endosymbiont, Buchnera aphidicola. The highly costly and over-replicating H. defensa strain H85 was associated with strongly reduced aphid expression of hemocytin, a marker of hemocytes in Drosophila. The closely related strain H15 was associated with downregulation of ubiquitin-related modifier 1, which is related to nutrient-sensing and oxidative stress in other organisms. Strain H402 was associated with strong differential regulation of a set of hypothetical proteins, the majority of which were only differentially regulated in presence of H402. Conclusions Overall, our results suggest that costs of different strains of H. defensa are likely caused by different mechanisms, and that these costs are imposed by interacting with the host rather than the host’s obligatory endosymbiont B. aphidicola. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07742-8.
Collapse
Affiliation(s)
- Heidi Kaech
- Aquatic Ecology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland. .,D-USYS, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland.
| | - Alice B Dennis
- Institute of Biochemistry and Biology, University Potsdam, Potsdam, Germany
| | - Christoph Vorburger
- Aquatic Ecology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland.,D-USYS, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| |
Collapse
|
16
|
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.
Collapse
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
| |
Collapse
|
17
|
Abstract
Insects have evolved various mechanisms to reliably transmit their beneficial bacterial symbionts to the next generation. Sap-sucking insects, including aphids, transmit symbionts by endocytosis of the symbiont into cells of the early embryo within the mother’s body. Many insects possess beneficial bacterial symbionts that occupy specialized host cells and are maternally transmitted. As a consequence of their host-restricted lifestyle, these symbionts often possess reduced genomes and cannot be cultured outside hosts, limiting their study. The bacterial species Serratia symbiotica was originally characterized as noncultured strains that live as mutualistic symbionts of aphids and are vertically transmitted through transovarial endocytosis within the mother’s body. More recently, culturable strains of S. symbiotica were discovered that retain a larger set of ancestral Serratia genes, are gut pathogens in aphid hosts, and are principally transmitted via a fecal-oral route. We find that these culturable strains, when injected into pea aphids, replicate in the hemolymph and are pathogenic. Unexpectedly, they are also capable of maternal transmission via transovarial endocytosis: using green fluorescent protein (GFP)-tagged strains, we observe that pathogenic S. symbiotica strains, but not Escherichia coli, are endocytosed into early embryos. Furthermore, pathogenic S. symbiotica strains are compartmentalized into specialized aphid cells in a fashion similar to that of mutualistic S. symbiotica strains during later stages of embryonic development. However, infected embryos do not appear to develop properly, and offspring infected by a transovarial route are not observed. Thus, cultured pathogenic strains of S. symbiotica have the latent capacity to transition to lifestyles as mutualistic symbionts of aphid hosts, but persistent vertical transmission is blocked by their pathogenicity. To transition into stably inherited symbionts, culturable S. symbiotica strains may need to adapt to regulate their titer, limit their pathogenicity, and/or provide benefits to aphids that outweigh their cost.
Collapse
|
18
|
Masson F, Lemaitre B. Growing Ungrowable Bacteria: Overview and Perspectives on Insect Symbiont Culturability. Microbiol Mol Biol Rev 2020; 84:e00089-20. [PMID: 33177190 PMCID: PMC7667007 DOI: 10.1128/mmbr.00089-20] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Insects are often involved in endosymbiosis, that is, the housing of symbiotic microbes within their tissues or within their cells. Endosymbionts are a major driving force in insects' evolution, because they dramatically affect their host physiology and allow them to adapt to new niches, for example, by complementing their diet or by protecting them against pathogens. Endosymbiotic bacteria are, however, fastidious and therefore difficult to manipulate outside of their hosts, especially intracellular species. The coevolution between hosts and endosymbionts leads to alterations in the genomes of endosymbionts, limiting their ability to cope with changing environments. Consequently, few insect endosymbionts are culturable in vitro and genetically tractable, making functional genetics studies impracticable on most endosymbiotic bacteria. However, recently, major progress has been made in manipulating several intracellular endosymbiont species in vitro, leading to astonishing discoveries on their physiology and the way they interact with their host. This review establishes a comprehensive picture of the in vitro tractability of insect endosymbiotic bacteria and addresses the reason why most species are not culturable. By compiling and discussing the latest developments in the design of custom media and genetic manipulation protocols, it aims at providing new leads to expand the range of tractable endosymbionts and foster genetic research on these models.
Collapse
Affiliation(s)
- Florent Masson
- Global Health Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Bruno Lemaitre
- Global Health Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| |
Collapse
|
19
|
Rossbacher S, Vorburger C. Prior adaptation of parasitoids improves biological control of symbiont-protected pests. Evol Appl 2020; 13:1868-1876. [PMID: 32908591 PMCID: PMC7463345 DOI: 10.1111/eva.12934] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/02/2020] [Accepted: 02/04/2020] [Indexed: 12/24/2022] Open
Abstract
There is increasing demand for sustainable pest management to reduce harmful effects of pesticides on the environment and human health. For pest aphids, biological control with parasitoid wasps provides a welcome alternative, particularly in greenhouses. However, aphids are frequently infected with the heritable bacterial endosymbiont Hamiltonella defensa, which increases resistance to parasitoids and thereby hampers biological control. Using the black bean aphid (Aphis fabae) and its main parasitoid Lysiphlebus fabarum, we tested whether prior adaptation of parasitoids can improve the control of symbiont-protected pests. We had parasitoid lines adapted to two different strains of H. defensa by experimental evolution, as well as parasitoids evolved on H. defensa-free aphids. We compared their ability to control caged aphid populations comprising 60% unprotected and 40% H. defensa-protected aphids, with both H. defensa strains present in the populations. Parasitoids that were not adapted to H. defensa had virtually no effect on aphid population dynamics compared to parasitoid-free controls, but one of the adapted lines and a mixture of both adapted lines controlled aphids successfully, strongly benefitting plant growth. Selection by parasitoids altered aphid population composition in a very specific manner. Aphid populations became dominated by H. defensa-protected aphids in the presence of parasitoids, and each adapted parasitoid line selected for the H. defensa strain it was not adapted to. This study shows, for the first time, that prior adaptation of parasitoids improves biological control of symbiont-protected pests, but the high specificity of parasitoid counter-resistance may represent a challenge for its implementation.
Collapse
Affiliation(s)
- Silvan Rossbacher
- Aquatic EcologyEawagDübendorfSwitzerland
- Institute of Integrative BiologyETH ZürichZürichSwitzerland
| | - Christoph Vorburger
- Aquatic EcologyEawagDübendorfSwitzerland
- Institute of Integrative BiologyETH ZürichZürichSwitzerland
| |
Collapse
|
20
|
Abstract
Beneficial microorganisms associated with animals derive their nutritional requirements entirely from the animal host, but the impact of these microorganisms on host metabolism is largely unknown. The focus of this study was the experimentally tractable tripartite symbiosis between the pea aphid Acyrthosiphon pisum, its obligate intracellular bacterial symbiont Buchnera, and the facultative bacterium Hamiltonella which is localized primarily to the aphid hemolymph (blood). Metabolome experiments on, first, multiple aphid genotypes that naturally bear or lack Hamiltonella and, second, one aphid genotype from which Hamiltonella was experimentally eliminated revealed no significant effects of Hamiltonella on aphid metabolite profiles, indicating that Hamiltonella does not cause major reconfiguration of host metabolism. However, the titer of just one metabolite, 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), displayed near-significant enrichment in Hamiltonella-positive aphids in both metabolome experiments. AICAR is a by-product of biosynthesis of the essential amino acid histidine in Buchnera and, hence, an index of histidine biosynthetic rates, suggesting that Buchnera-mediated histidine production is elevated in Hamiltonella-bearing aphids. Consistent with this prediction, aphids fed on [13C]histidine yielded a significantly elevated 12C/13C ratio of histidine in Hamiltonella-bearing aphids, indicative of increased (∼25%) histidine synthesized de novo by Buchnera However, in silico analysis predicted an increase of only 0.8% in Buchnera histidine synthesis in Hamiltonella-bearing aphids. We hypothesize that Hamiltonella imposes increased host demand for histidine, possibly for heightened immune-related functions. These results demonstrate that facultative bacteria can alter the dynamics of host metabolic interactions with co-occurring microorganisms, even when the overall metabolic homeostasis of the host is not substantially perturbed.IMPORTANCE Although microbial colonization of the internal tissues of animals generally causes septicemia and death, various animals are persistently associated with benign or beneficial microorganisms in their blood or internal organs. The metabolic consequences of these persistent associations for the animal host are largely unknown. Our research on the facultative bacterium Hamiltonella, localized primarily to the hemolymph of pea aphids, demonstrated that although Hamiltonella imposed no major reconfiguration of the aphid metabolome, it did alter the metabolic relations between the aphid and its obligate intracellular symbiont, Buchnera Specifically, Buchnera produced more histidine in Hamiltonella-positive aphids to support both Hamiltonella demand for histidine and Hamiltonella-induced increase in host demand. This study demonstrates how microorganisms associated with internal tissues of animals can influence specific aspects of metabolic interactions between the animal host and co-occurring microorganisms.
Collapse
|
21
|
Rouïl J, Jousselin E, Coeur d’acier A, Cruaud C, Manzano-Marín A. The Protector within: Comparative Genomics of APSE Phages across Aphids Reveals Rampant Recombination and Diverse Toxin Arsenals. Genome Biol Evol 2020; 12:878-889. [PMID: 32386316 PMCID: PMC7313666 DOI: 10.1093/gbe/evaa089] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2020] [Indexed: 12/13/2022] Open
Abstract
Phages can fundamentally alter the physiology and metabolism of their hosts. Although these phages are ubiquitous in the bacterial world, they have seldom been described among endosymbiotic bacteria. One notable exception is the APSE phage that is found associated with the gammaproteobacterial Hamiltonella defensa, hosted by several insect species. This secondary facultative endosymbiont is not necessary for the survival of its hosts but can infect certain individuals or even whole populations. Its infection in aphids is often associated with protection against parasitoid wasps. This protective phenotype has actually been linked to the infection of the symbiont strain with an APSE, which carries a toxin cassette that varies among so-called "types." In the present work, we seek to expand our understanding of the diversity of APSE phages as well as the relations of their Hamiltonella hosts. For this, we assembled and annotated the full genomes of 16 APSE phages infecting Hamiltonella symbionts across ten insect species. Molecular and phylogenetic analyses suggest that recombination has occurred repeatedly among lineages. Comparative genomics of the phage genomes revealed two variable regions that are useful for phage typing. Additionally, we find that mobile elements could play a role in the acquisition of new genes in the toxin cassette. Altogether, we provide an unprecedented view of APSE diversity and their genome evolution across aphids. This genomic investigation will provide a valuable resource for the design and interpretation of experiments aiming at understanding the protective phenotype these phages confer to their insect hosts.
Collapse
Affiliation(s)
- Jeff Rouïl
- UMR 1062 Centre de Biologie pour la Gestion des Populations, INRAE, CIRAD, IRD, Montpellier SupAgro, Université de Montpellier, France
| | - Emmanuelle Jousselin
- UMR 1062 Centre de Biologie pour la Gestion des Populations, INRAE, CIRAD, IRD, Montpellier SupAgro, Université de Montpellier, France
| | - Armelle Coeur d’acier
- UMR 1062 Centre de Biologie pour la Gestion des Populations, INRAE, CIRAD, IRD, Montpellier SupAgro, Université de Montpellier, France
| | - Corinne Cruaud
- Genoscope, Institut de Biologie François-Jacob, Commissariat à l’Energie Atomique (CEA), Université Paris-Saclay, Évry, France
| | | |
Collapse
|
22
|
Patel V, Chevignon G, Manzano-Marín A, Brandt JW, Strand MR, Russell JA, Oliver KM. Cultivation-Assisted Genome of Candidatus Fukatsuia symbiotica; the Enigmatic "X-Type" Symbiont of Aphids. Genome Biol Evol 2020; 11:3510-3522. [PMID: 31725149 PMCID: PMC7145644 DOI: 10.1093/gbe/evz252] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/13/2019] [Indexed: 12/19/2022] Open
Abstract
Heritable symbionts are common in terrestrial arthropods and often provide beneficial services to hosts. Unlike obligate, nutritional symbionts that largely persist under strict host control within specialized host cells, heritable facultative symbionts exhibit large variation in within-host lifestyles and services rendered with many retaining the capacity to transition among roles. One enigmatic symbiont, Candidatus Fukatsuia symbiotica, frequently infects aphids with reported roles ranging from pathogen, defensive symbiont, mutualism exploiter, and nutritional co-obligate symbiont. Here, we used an in vitro culture-assisted protocol to sequence the genome of a facultative strain of Fukatsuia from pea aphids (Acyrthosiphon pisum). Phylogenetic and genomic comparisons indicate that Fukatsuia is an aerobic heterotroph, which together with Regiella insecticola and Hamiltonella defensa form a clade of heritable facultative symbionts within the Yersiniaceae (Enterobacteriales). These three heritable facultative symbionts largely share overlapping inventories of genes associated with housekeeping functions, metabolism, and nutrient acquisition, while varying in complements of mobile DNA. One unusual feature of Fukatsuia is its strong tendency to occur as a coinfection with H. defensa. However, the overall similarity of gene inventories among aphid heritable facultative symbionts suggests that metabolic complementarity is not the basis for coinfection, unless playing out on a H. defensa strain-specific basis. We also compared the pea aphid Fukatsuia with a strain from the aphid Cinara confinis (Lachninae) where it is reported to have transitioned to co-obligate status to support decaying Buchnera function. Overall, the two genomes are very similar with no clear genomic signatures consistent with such a transition, which suggests co-obligate status in C. confinis was a recent event.
Collapse
Affiliation(s)
- Vilas Patel
- Department of Entomology, University of Georgia
| | | | | | | | | | | | | |
Collapse
|
23
|
More Is Not Always Better: Coinfections with Defensive Symbionts Generate Highly Variable Outcomes. Appl Environ Microbiol 2020; 86:AEM.02537-19. [PMID: 31862723 DOI: 10.1128/aem.02537-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 12/12/2019] [Indexed: 11/20/2022] Open
Abstract
Animal-associated microbes are highly variable, contributing to a diverse set of symbiont-mediated phenotypes. Given that host and symbiont genotypes, and their interactions, can impact symbiont-based phenotypes across environments, there is potential for extensive variation in fitness outcomes. Pea aphids, Acyrthosiphon pisum, host a diverse assemblage of heritable facultative symbionts (HFS) with characterized roles in host defense. Protective phenotypes have been largely studied as single infections, but pea aphids often carry multiple HFS species, and particular combinations may be enriched or depleted compared to expectations based on chance. Here, we examined the consequences of single infection versus coinfection with two common HFS exhibiting variable enrichment, the antiparasitoid Hamiltonella defensa and the antipathogen Regiella insecticola, across three host genotypes and environments. As expected, single infections with either H. defensa or R. insecticola raised defenses against their respective targets. Single infections with protective H. defensa lowered aphid fitness in the absence of enemy challenge, while R. insecticola was comparatively benign. However, as a coinfection, R. insecticola ameliorated H. defensa infection costs. Coinfected aphids continued to receive antiparasitoid protection from H. defensa, but protection was weakened by R. insecticola in two clones. Notably, H. defensa eliminated survival benefits conferred after pathogen exposure by coinfecting R. insecticola Since pathogen sporulation was suppressed by R. insecticola in coinfected aphids, the poor performance likely stemmed from H. defensa-imposed costs rather than weakened defenses. Our results reveal a complex set of coinfection outcomes which may partially explain natural infection patterns and suggest that symbiont-based phenotypes may not be easily predicted based solely on infection status.IMPORTANCE The hyperdiverse arthropods often harbor maternally transmitted bacteria that protect against natural enemies. In many species, low-diversity communities of heritable symbionts are common, providing opportunities for cooperation and conflict among symbionts, which can impact the defensive services rendered. Using the pea aphid, a model for defensive symbiosis, we show that coinfections with two common defensive symbionts, the antipathogen Regiella and the antiparasite Hamiltonella, produce outcomes that are highly variable compared to single infections, which consistently protect against designated enemies. Compared to single infections, coinfections often reduced defensive services during enemy challenge yet improved aphid fitness in the absence of enemies. Thus, infection with multiple symbionts does not necessarily create generalist aphids with "Swiss army knife" defenses against numerous enemies. Instead, particular combinations of symbionts may be favored for a variety of reasons, including their abilities to lessen the costs of other defensive symbionts when enemies are not present.
Collapse
|
24
|
Manzano-Marı N A, Coeur d'acier A, Clamens AL, Orvain C, Cruaud C, Barbe V, Jousselin E. Serial horizontal transfer of vitamin-biosynthetic genes enables the establishment of new nutritional symbionts in aphids' di-symbiotic systems. THE ISME JOURNAL 2020; 14:259-273. [PMID: 31624345 PMCID: PMC6908640 DOI: 10.1038/s41396-019-0533-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 08/24/2019] [Accepted: 09/07/2019] [Indexed: 02/07/2023]
Abstract
Many insects depend on obligate mutualistic bacteria to provide essential nutrients lacking from their diet. Most aphids, whose diet consists of phloem, rely on the bacterial endosymbiont Buchnera aphidicola to supply essential amino acids and B vitamins. However, in some aphid species, provision of these nutrients is partitioned between Buchnera and a younger bacterial partner, whose identity varies across aphid lineages. Little is known about the origin and the evolutionary stability of these di-symbiotic systems. It is also unclear whether the novel symbionts merely compensate for losses in Buchnera or carry new nutritional functions. Using whole-genome endosymbiont sequences of nine Cinara aphids that harbour an Erwinia-related symbiont to complement Buchnera, we show that the Erwinia association arose from a single event of symbiont lifestyle shift, from a free-living to an obligate intracellular one. This event resulted in drastic genome reduction, long-term genome stasis, and co-divergence with aphids. Fluorescence in situ hybridisation reveals that Erwinia inhabits its own bacteriocytes near Buchnera's. Altogether these results depict a scenario for the establishment of Erwinia as an obligate symbiont that mirrors Buchnera's. Additionally, we found that the Erwinia vitamin-biosynthetic genes not only compensate for Buchnera's deficiencies, but also provide a new nutritional function; whose genes have been horizontally acquired from a Sodalis-related bacterium. A subset of these genes have been subsequently transferred to a new Hamiltonella co-obligate symbiont in one specific Cinara lineage. These results show that the establishment and dynamics of multi-partner endosymbioses can be mediated by lateral gene transfers between co-ocurring symbionts.
Collapse
Affiliation(s)
- Alejandro Manzano-Marı N
- UMR 1062 Centre de Biologie pour la Gestion des Populations, INRA, CIRAD, IRD, Montpellier SupAgro, Univ. Montpellier, Montpellier, France.
| | - Armelle Coeur d'acier
- UMR 1062 Centre de Biologie pour la Gestion des Populations, INRA, CIRAD, IRD, Montpellier SupAgro, Univ. Montpellier, Montpellier, France
| | - Anne-Laure Clamens
- UMR 1062 Centre de Biologie pour la Gestion des Populations, INRA, CIRAD, IRD, Montpellier SupAgro, Univ. Montpellier, Montpellier, France
| | - Céline Orvain
- Institut de Biologie François-Jacob, CEA, Genoscope, Évry Cedex, France
| | - Corinne Cruaud
- Institut de Biologie François-Jacob, CEA, Genoscope, Évry Cedex, France
| | - Valérie Barbe
- Institut de Biologie François-Jacob, CEA, Genoscope, Évry Cedex, France
| | - Emmanuelle Jousselin
- UMR 1062 Centre de Biologie pour la Gestion des Populations, INRA, CIRAD, IRD, Montpellier SupAgro, Univ. Montpellier, Montpellier, France
| |
Collapse
|
25
|
Li Q, Fan J, Sun J, Zhang Y, Hou M, Chen J. Anti-plant Defense Response Strategies Mediated by the Secondary Symbiont Hamiltonella defensa in the Wheat Aphid Sitobion miscanthi. Front Microbiol 2019; 10:2419. [PMID: 31708894 PMCID: PMC6823553 DOI: 10.3389/fmicb.2019.02419] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 10/07/2019] [Indexed: 11/13/2022] Open
Abstract
Bacterial symbionts are omnipresent in insects, particularly aphids, and often exert important effects on the host ecology; however, examples of symbionts that mediate herbivore-plant interactions remain limited. Here, three clones with identical genetic backgrounds were established: a Hamiltonella defensa-free clone, H. defensa-infected clone and H. defensa-cured clone. H. defensa infection was found to increase the fitness of Sitobion miscanthi by increasing the total number of offspring and decreasing the age of first reproduction. Furthermore, gene expression studies and phytohormone measurement showed that feeding by the Hamiltonella-infected clone suppressed the salicylic acid (SA)- and jasmonic acid (JA)-related defense pathways and SA/JA accumulation in wheat plants relative to feeding by the other two clones. Additionally, after feeding by the Hamiltonella-infected clone, the activity levels of the defense-related enzymes polyphenol oxidase (PPO) and peroxidase (POD) in wheat plants were significantly decreased compared with the levels observed after feeding by the other two clones. Taken together, these data reveal for the first time the potential role of H. defensa of S. miscanthi in mediating the anti-plant defense responses of aphids.
Collapse
Affiliation(s)
- Qian Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jia Fan
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - JingXuan Sun
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yong Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - MaoLin Hou
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - JuLian Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- MARA-CABI Joint Laboratory for Bio-Safety, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| |
Collapse
|
26
|
Lynn-Bell NL, Strand MR, Oliver KM. Bacteriophage acquisition restores protective mutualism. Microbiology (Reading) 2019; 165:985-989. [DOI: 10.1099/mic.0.000816] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
| | - Michael R. Strand
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Kerry M. Oliver
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| |
Collapse
|
27
|
Blow F, Douglas AE. The hemolymph microbiome of insects. JOURNAL OF INSECT PHYSIOLOGY 2019; 115:33-39. [PMID: 30953618 DOI: 10.1016/j.jinsphys.2019.04.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 03/27/2019] [Accepted: 04/02/2019] [Indexed: 06/09/2023]
Abstract
Hemolymph has long been recognized as a key mediator of nutritional and immunological homeostasis in insects, with the tacit understanding that hemolymph is a hostile environment for microorganisms, and microbiologically sterile in healthy insects. Recent research is overturning the conventional wisdom, and there is now overwhelming evidence that various non-pathogenic microorganisms can stably or transiently inhabit hemolymph in a diversity of insects. Most is known about Spiroplasma, especially in Drosophila species, and secondary symbionts of the Enterobacteriaceae, notably Hamiltonella defensa, in aphids. These bacteria require many nutrients, representing a likely drain on host nutritional resources, and they persist in the hemolymph by a combination of evasion and tolerance of insect immune effectors. These traits can be costly to the insect host. For some hemolymph microorganisms, these costs are balanced by other traits beneficial to the insect, notably protection against natural enemies mediated by specific toxins or competition for key nutrients. Three key priorities for future research are: to investigate the prevalence and taxonomic diversity of hemolymph microorganisms in insects; to establish the role of host nutritional and immune factors as determinants of the abundance and proliferation rates of hemolymph microorganisms; and to integrate the developing understanding of these microorganisms and their impacts (both costs and benefits) on insect nutrition and immune function into the wider study of insect physiology.
Collapse
Affiliation(s)
- Frances Blow
- Department of Entomology, Cornell University, Ithaca, NY 14853, USA
| | - Angela E Douglas
- Department of Entomology, Cornell University, Ithaca, NY 14853, USA; Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
| |
Collapse
|
28
|
Oliver KM, Higashi CH. Variations on a protective theme: Hamiltonella defensa infections in aphids variably impact parasitoid success. CURRENT OPINION IN INSECT SCIENCE 2019; 32:1-7. [PMID: 31113620 DOI: 10.1016/j.cois.2018.08.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 08/27/2018] [Indexed: 06/09/2023]
Abstract
Protective mutualisms are common in nature and include insect infections with cryptic symbionts that defend against pathogens and parasites. An archetypal defensive symbiont, Hamiltonella defensa protects aphids against parasitoids by disabling wasp development. Successful defense requires H. defensa infection with bacteriophages (APSEs), which play other key roles in mutualism maintenance. Genomes of H. defensa strains are highly similar in gene inventories, varying primarily in mobile element content. Protective phenotypes are highly variable across aphid models depending on H. defensa/APSE, aphid and wasp genotypes. Infection frequencies of H. defensa are highly dynamic in field populations, influenced by a variety of selective and non-selective factors confounding biological control implications. Overall, H. defensa infections likely represent a global aphid protection network with effects radiating outward from focal interactions.
Collapse
Affiliation(s)
- Kerry M Oliver
- Department of Entomology, University of Georgia, Athens, GA 30602, USA.
| | | |
Collapse
|
29
|
Li Q, Fan J, Sun J, Wang MQ, Chen J. Plant-Mediated Horizontal Transmission of Hamiltonella defensa in the Wheat Aphid Sitobion miscanthi. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:13367-13377. [PMID: 30516997 DOI: 10.1021/acs.jafc.8b04828] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Hamiltonella defensa is mainly vertically transmitted, but evidence suggests that horizontal transmission may occur. Here, the first case of plant-mediated horizontal transmission of H. defensa between wheat aphids, Sitobion miscanthi, was reported. H. defensa was harbored in sheath cells, secondary bacteriocytes, and hemolymph. After Hamiltonella-infected aphids fed on wheat leaves, H. defensa was observed in aphid stylets and plant phloem. H. defensa persisted in wheat leaves for at least 10 days. Most Hamiltonella-uninfected aphids became infected with H. defensa after sustained feeding on infected plant leaves and showed almost 100% stable vertical transmission over the next five generations. These horizontal transmission experiments were replicated using two other plants, rice and corn, and two different wheat aphid species, Rhopalosiphum padi and Schizaphis graminum. Surprisingly, aphid feeding induced plant infection only locally rather than systemically in leaves. Our findings indicate that plants may act as horizontal transmission intermediaries, contributing to the ubiquity of the otherwise maternally inherited H. defensa.
Collapse
Affiliation(s)
- Qian Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection , Chinese Academy of Agricultural Sciences , Beijing 100193 , People's Republic of China
- College of Plant Science and Technology , Huazhong Agricultural University , Wuhan , Hubei 430070 , People's Republic of China
| | - Jia Fan
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection , Chinese Academy of Agricultural Sciences , Beijing 100193 , People's Republic of China
| | - Jingxuan Sun
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection , Chinese Academy of Agricultural Sciences , Beijing 100193 , People's Republic of China
| | - Man-Qun Wang
- College of Plant Science and Technology , Huazhong Agricultural University , Wuhan , Hubei 430070 , People's Republic of China
| | - Julian Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection , Chinese Academy of Agricultural Sciences , Beijing 100193 , People's Republic of China
| |
Collapse
|
30
|
Guyomar C, Legeai F, Jousselin E, Mougel C, Lemaitre C, Simon JC. Multi-scale characterization of symbiont diversity in the pea aphid complex through metagenomic approaches. MICROBIOME 2018; 6:181. [PMID: 30305166 PMCID: PMC6180509 DOI: 10.1186/s40168-018-0562-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 09/20/2018] [Indexed: 05/27/2023]
Abstract
BACKGROUND Most metazoans are involved in durable relationships with microbes which can take several forms, from mutualism to parasitism. The advances of NGS technologies and bioinformatics tools have opened opportunities to shed light on the diversity of microbial communities and to give some insights into the functions they perform in a broad array of hosts. The pea aphid is a model system for the study of insect-bacteria symbiosis. It is organized in a complex of biotypes, each adapted to specific host plants. It harbors both an obligatory symbiont supplying key nutrients and several facultative symbionts bringing additional functions to the host, such as protection against biotic and abiotic stresses. However, little is known on how the symbiont genomic diversity is structured at different scales: across host biotypes, among individuals of the same biotype, or within individual aphids, which limits our understanding on how these multi-partner symbioses evolve and interact. RESULTS We present a framework well adapted to the study of genomic diversity and evolutionary dynamics of the pea aphid holobiont from metagenomic read sets, based on mapping to reference genomes and whole genome variant calling. Our results revealed that the pea aphid microbiota is dominated by a few heritable bacterial symbionts reported in earlier works, with no discovery of new microbial associates. However, we detected a large and heterogeneous genotypic diversity associated with the different symbionts of the pea aphid. Partitioning analysis showed that this fine resolution diversity is distributed across the three considered scales. Phylogenetic analyses highlighted frequent horizontal transfers of facultative symbionts between host lineages, indicative of flexible associations between the pea aphid and its microbiota. However, the evolutionary dynamics of symbiotic associations strongly varied depending on the symbiont, reflecting different histories and possible constraints. In addition, at the intra-host scale, we showed that different symbiont strains may coexist inside the same aphid host. CONCLUSIONS We present a methodological framework for the detailed analysis of NGS data from microbial communities of moderate complexity and gave major insights into the extent of diversity in pea aphid-symbiont associations and the range of evolutionary trajectories they could take.
Collapse
Affiliation(s)
- Cervin Guyomar
- INRA, UMR 1349 INRA/Agrocampus Ouest/Université Rennes 1, Institut de Génétique, Environnement et Protection des Plantes (IGEPP), Le Rheu, France
- Université Rennes 1, Inria, CNRS, IRISA, F-35000, Rennes, France
| | - Fabrice Legeai
- INRA, UMR 1349 INRA/Agrocampus Ouest/Université Rennes 1, Institut de Génétique, Environnement et Protection des Plantes (IGEPP), Le Rheu, France
- Université Rennes 1, Inria, CNRS, IRISA, F-35000, Rennes, France
| | - Emmanuelle Jousselin
- INRA, UMR CBGP (INRA/IRD/Cirad/Montpellier SupAgro), Campus International de Baillarguet, Montpellier, France
| | - Christophe Mougel
- INRA, UMR 1349 INRA/Agrocampus Ouest/Université Rennes 1, Institut de Génétique, Environnement et Protection des Plantes (IGEPP), Le Rheu, France
| | - Claire Lemaitre
- Université Rennes 1, Inria, CNRS, IRISA, F-35000, Rennes, France
| | - Jean-Christophe Simon
- INRA, UMR 1349 INRA/Agrocampus Ouest/Université Rennes 1, Institut de Génétique, Environnement et Protection des Plantes (IGEPP), Le Rheu, France.
| |
Collapse
|
31
|
Douglas AE. Omics and the metabolic function of insect-microbial symbioses. CURRENT OPINION IN INSECT SCIENCE 2018; 29:1-6. [PMID: 30551814 DOI: 10.1016/j.cois.2018.05.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 05/23/2018] [Indexed: 06/09/2023]
Abstract
Omic studies of metabolic interactions between insects and their microbial symbionts enable us to construct precise hypotheses, especially regarding the metabolic services provided by microbial partners and the identity of metabolites exchanged between microorganisms and the insect host. Valuable sources of information include the complement of metabolism-related genes in the microbial partners, and differences in the abundance of transcripts, proteins or metabolites, either between microbe-bearing organs and the whole body or between insects bearing and lacking microbial symbionts. Hypotheses generated from omic data can, most productively, be tested by experiments using reverse genetics for precise manipulation of the gene expression.
Collapse
Affiliation(s)
- Angela E Douglas
- Department of Entomology and Department of Molecular Biology & Genetics, Cornell University, Ithaca, NY 14853, USA.
| |
Collapse
|