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Shan HW, Xia XJ, Feng YL, Wu W, Li HJ, Sun ZT, Li JM, Chen JP. The plant-sucking insect selects assembly of the gut microbiota from environment to enhance host reproduction. NPJ Biofilms Microbiomes 2024; 10:64. [PMID: 39080326 PMCID: PMC11289440 DOI: 10.1038/s41522-024-00539-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 07/22/2024] [Indexed: 08/02/2024] Open
Abstract
Plant-sucking insects have intricate associations with a diverse array of microorganisms to facilitate their adaptation to specific ecological niches. The midgut of phytophagous true bugs is generally structured into four distinct compartments to accommodate their microbiota. Nevertheless, there is limited understanding regarding the origins of these gut microbiomes, the mechanisms behind microbial community assembly, and the interactions between gut microbiomes and their insect hosts. In this study, we conducted a comprehensive survey of microbial communities within the midgut compartments of a bean bug Riptortus pedestris, soybean plant, and bulk soil across 12 distinct geographical fields in China, utilizing high-throughput sequencing of the 16 S rRNA gene. Our findings illuminated that gut microbiota of the plant-sucking insects predominantly originated from the surrounding soil environment, and plants also play a subordinate role in mediating microbial acquisition for the insects. Furthermore, our investigation suggested that the composition of the insect gut microbiome was probably shaped by host selection and/or microbe-microbe interactions at the gut compartment level, with marginal influence from soil and geographical factors. Additionally, we had unveiled a noteworthy dynamic in the acquisition of core bacterial taxa, particularly Burkholderia, which were initially sourced from the environment and subsequently enriched within the insect midgut compartments. This bacterial enrichment played a significant role in enhancing insect host reproduction. These findings contribute to our evolving understanding of microbiomes within the insect-plant-soil ecosystem, shedding additional light on the intricate interactions between insects and their microbiomes that underpin the ecological significance of microbial partnerships in host adaptation.
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Affiliation(s)
- Hong-Wei Shan
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MARA and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, 315211, China.
| | - Xie-Jiang Xia
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MARA and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, 315211, China
| | - Yi-Lu Feng
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MARA and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, 315211, China
| | - Wei Wu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MARA and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, 315211, China
| | - Hong-Jie Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MARA and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, 315211, China
| | - Zong-Tao Sun
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MARA and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, 315211, China
| | - Jun-Min Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MARA and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, 315211, China
| | - Jian-Ping Chen
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MARA and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, 315211, China.
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Holt JR, Cavichiolli de Oliveira N, Medina RF, Malacrinò A, Lindsey ARI. Insect-microbe interactions and their influence on organisms and ecosystems. Ecol Evol 2024; 14:e11699. [PMID: 39041011 PMCID: PMC11260886 DOI: 10.1002/ece3.11699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 06/14/2024] [Accepted: 06/21/2024] [Indexed: 07/24/2024] Open
Abstract
Microorganisms are important associates of insect and arthropod species. Insect-associated microbes, including bacteria, fungi, and viruses, can drastically impact host physiology, ecology, and fitness, while many microbes still have no known role. Over the past decade, we have increased our knowledge of the taxonomic composition and functional roles of insect-associated microbiomes and viromes. There has been a more recent shift toward examining the complexity of microbial communities, including how they vary in response to different factors (e.g., host genome, microbial strain, environment, and time), and the consequences of this variation for the host and the wider ecological community. We provide an overview of insect-microbe interactions, the variety of associated microbial functions, and the evolutionary ecology of these relationships. We explore the influence of the environment and the interactive effects of insects and their microbiomes across trophic levels. Additionally, we discuss the potential for subsequent synergistic and reciprocal impacts on the associated microbiomes, ecological interactions, and communities. Lastly, we discuss some potential avenues for the future of insect-microbe interactions that include the modification of existing microbial symbionts as well as the construction of synthetic microbial communities.
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Affiliation(s)
| | | | - Raul F. Medina
- Department of EntomologyTexas A&M University, Minnie Bell Heep CenterCollege StationTexasUSA
| | - Antonino Malacrinò
- Department of AgricultureUniversità Degli Studi Mediterranea di Reggio CalabriaReggio CalabriaItaly
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3
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Lachat J, Lextrait G, Jouan R, Boukherissa A, Yokota A, Jang S, Ishigami K, Futahashi R, Cossard R, Naquin D, Costache V, Augusto L, Tissières P, Biondi EG, Alunni B, Timchenko T, Ohbayashi T, Kikuchi Y, Mergaert P. Hundreds of antimicrobial peptides create a selective barrier for insect gut symbionts. Proc Natl Acad Sci U S A 2024; 121:e2401802121. [PMID: 38865264 PMCID: PMC11194567 DOI: 10.1073/pnas.2401802121] [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: 02/04/2024] [Accepted: 05/08/2024] [Indexed: 06/14/2024] Open
Abstract
The spatial organization of gut microbiota is crucial for the functioning of the gut ecosystem, although the mechanisms that organize gut bacterial communities in microhabitats are only partially understood. The gut of the insect Riptortus pedestris has a characteristic microbiota biogeography with a multispecies community in the anterior midgut and a monospecific bacterial population in the posterior midgut. We show that the posterior midgut region produces massively hundreds of specific antimicrobial peptides (AMPs), the Crypt-specific Cysteine-Rich peptides (CCRs) that have membrane-damaging antimicrobial activity against diverse bacteria but posterior midgut symbionts have elevated resistance. We determined by transposon-sequencing the genetic repertoire in the symbiont Caballeronia insecticola to manage CCR stress, identifying different independent pathways, including AMP-resistance pathways unrelated to known membrane homeostasis functions as well as cell envelope functions. Mutants in the corresponding genes have reduced capacity to colonize the posterior midgut, demonstrating that CCRs create a selective barrier and resistance is crucial in gut symbionts. Moreover, once established in the gut, the bacteria differentiate into a CCR-sensitive state, suggesting a second function of the CCR peptide arsenal in protecting the gut epithelia or mediating metabolic exchanges between the host and the gut symbionts. Our study highlights the evolution of an extreme diverse AMP family that likely contributes to establish and control the gut microbiota.
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Affiliation(s)
- Joy Lachat
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette91198, France
| | - Gaëlle Lextrait
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette91198, France
| | - Romain Jouan
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette91198, France
| | - Amira Boukherissa
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette91198, France
| | - Aya Yokota
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette91198, France
| | - Seonghan Jang
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Hokkaido Center, Sapporo062-8517, Japan
- Unit of Applied Biological Chemistry, Graduate School of Agriculture, Hokkaido University, 060-8589Sapporo, Japan
| | - Kota Ishigami
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Hokkaido Center, Sapporo062-8517, Japan
- Unit of Applied Biological Chemistry, Graduate School of Agriculture, Hokkaido University, 060-8589Sapporo, Japan
| | - Ryo Futahashi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba305-8566, Japan
| | - Raynald Cossard
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette91198, France
| | - Delphine Naquin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette91198, France
| | - Vlad Costache
- MIMA2 Imaging Core Facility, Microscopie et Imagerie des Microorganismes, Animaux et Aliments (MIMA2), INRAe, Jouy-en-Josas78352, France
| | - Luis Augusto
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette91198, France
| | - Pierre Tissières
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette91198, France
| | - Emanuele G. Biondi
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette91198, France
| | - Benoît Alunni
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette91198, France
| | - Tatiana Timchenko
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette91198, France
| | - Tsubasa Ohbayashi
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette91198, France
| | - Yoshitomo Kikuchi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Hokkaido Center, Sapporo062-8517, Japan
- Unit of Applied Biological Chemistry, Graduate School of Agriculture, Hokkaido University, 060-8589Sapporo, Japan
| | - Peter Mergaert
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette91198, France
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Ludington WB. The importance of host physical niches for the stability of gut microbiome composition. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230066. [PMID: 38497267 PMCID: PMC10945397 DOI: 10.1098/rstb.2023.0066] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 12/04/2023] [Indexed: 03/19/2024] Open
Abstract
Gut bacteria are prevalent throughout the Metazoa and form complex microbial communities associated with food breakdown, nutrient provision and disease prevention. How hosts acquire and maintain a consistent bacterial flora remains mysterious even in the best-studied animals, including humans, mice, fishes, squid, bugs, worms and flies. This essay visits the evidence that hosts have co-evolved relationships with specific bacteria and that some of these relationships are supported by specialized physical niches that select, sequester and maintain microbial symbionts. Genetics approaches could uncover the mechanisms for recruiting and maintaining the stable and consistent members of the microbiome. This article is part of the theme issue 'Sculpting the microbiome: how host factors determine and respond to microbial colonization'.
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Affiliation(s)
- William B. Ludington
- Department of Biosphere Sciences and Engineering, Carnegie Institution for Science, Baltimore, MD 21218, USA
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
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5
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Schaub GA. Interaction of Trypanosoma cruzi, Triatomines and the Microbiota of the Vectors-A Review. Microorganisms 2024; 12:855. [PMID: 38792688 PMCID: PMC11123833 DOI: 10.3390/microorganisms12050855] [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: 03/03/2024] [Revised: 04/15/2024] [Accepted: 04/17/2024] [Indexed: 05/26/2024] Open
Abstract
This review summarizes the interactions between Trypanosoma cruzi, the etiologic agent of Chagas disease, its vectors, triatomines, and the diverse intestinal microbiota of triatomines, which includes mutualistic symbionts, and highlights open questions. T. cruzi strains show great biological heterogeneity in their development and their interactions. Triatomines differ from other important vectors of diseases in their ontogeny and the enzymes used to digest blood. Many different bacteria colonize the intestinal tract of triatomines, but only Actinomycetales have been identified as mutualistic symbionts. Effects of the vector on T. cruzi are indicated by differences in the ability of T. cruzi to establish in the triatomines and in colonization peculiarities, i.e., proliferation mainly in the posterior midgut and rectum and preferential transformation into infectious metacyclic trypomastigotes in the rectum. In addition, certain forms of T. cruzi develop after feeding and during starvation of triatomines. Negative effects of T. cruzi on the triatomine vectors appear to be particularly evident when the triatomines are stressed and depend on the T. cruzi strain. Effects on the intestinal immunity of the triatomines are induced by ingested blood-stage trypomastigotes of T. cruzi and affect the populations of many non-symbiotic intestinal bacteria, but not all and not the mutualistic symbionts. After the knockdown of antimicrobial peptides, the number of non-symbiotic bacteria increases and the number of T. cruzi decreases. Presumably, in long-term infections, intestinal immunity is suppressed, which supports the growth of specific bacteria, depending on the strain of T. cruzi. These interactions may provide an approach to disrupt T. cruzi transmission.
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Affiliation(s)
- Günter A Schaub
- Zoology/Parasitology, Ruhr-University Bochum, Universitätsstr. 150, 44780 Bochum, Germany
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6
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Jang S, Ishigami K, Mergaert P, Kikuchi Y. Ingested soil bacteria breach gut epithelia and prime systemic immunity in an insect. Proc Natl Acad Sci U S A 2024; 121:e2315540121. [PMID: 38437561 PMCID: PMC10945853 DOI: 10.1073/pnas.2315540121] [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: 09/07/2023] [Accepted: 01/11/2024] [Indexed: 03/06/2024] Open
Abstract
Insects lack acquired immunity and were thought to have no immune memory, but recent studies reported a phenomenon called immune priming, wherein sublethal dose of pathogens or nonpathogenic microbes stimulates immunity and prevents subsequential pathogen infection. Although the evidence for insect immune priming is accumulating, the underlying mechanisms are still unclear. The bean bug Riptortus pedestris acquires its gut microbiota from ambient soil and spatially structures them into a multispecies and variable community in the anterior midgut and a specific, monospecies Caballeronia symbiont population in the posterior region. We demonstrate that a particular Burkholderia strain colonizing the anterior midgut stimulates systemic immunity by penetrating gut epithelia and migrating into the hemolymph. The activated immunity, consisting of a humoral and a cellular response, had no negative effect on the host fitness, but on the contrary protected the insect from subsequent infection by pathogenic bacteria. Interruption of contact between the Burkholderia strain and epithelia of the gut weakened the host immunity back to preinfection levels and made the insects more vulnerable to microbial infection, demonstrating that persistent acquisition of environmental bacteria is important to maintain an efficient immunity.
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Affiliation(s)
- Seonghan Jang
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Hokkaido Center, 062-8517Sapporo, Japan
| | - Kota Ishigami
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Hokkaido Center, 062-8517Sapporo, Japan
| | - Peter Mergaert
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, 91198Gif-sur-Yvette, France
| | - Yoshitomo Kikuchi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Hokkaido Center, 062-8517Sapporo, Japan
- Unit of Applied Biological Chemistry, Graduate School of Agriculture, Hokkaido University, 060-8589Sapporo, Japan
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7
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Lee J, Jeong B, Kim J, Cho JH, Byeon JH, Lee BL, Kim JK. Specialized digestive mechanism for an insect-bacterium gut symbiosis. THE ISME JOURNAL 2024; 18:wrad021. [PMID: 38365249 PMCID: PMC10811733 DOI: 10.1093/ismejo/wrad021] [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: 11/10/2023] [Revised: 12/04/2023] [Accepted: 12/06/2023] [Indexed: 02/18/2024]
Abstract
In Burkholderia-Riptortus symbiosis, the host bean bug Riptortus pedestris harbors Burkholderia symbionts in its symbiotic organ, M4 midgut, for use as a nutrient source. After occupying M4, excess Burkholderia symbionts are moved to the M4B region, wherein they are effectively digested and absorbed. Previous studies have shown that M4B has strong symbiont-specific antibacterial activity, which is not because of the expression of antimicrobial peptides but rather because of the expression of digestive enzymes, mainly cathepsin L protease. However, in this study, inhibition of cathepsin L activity did not reduce the bactericidal activity of M4B, indicating that there is an unknown digestive mechanism that renders specifically potent bactericidal activity against Burkholderia symbionts. Transmission electron microscopy revealed that the lumen of symbiotic M4B was filled with a fibrillar matter in contrast to the empty lumen of aposymbiotic M4B. Using chromatographic and electrophoretic analyses, we found that the bactericidal substances in M4B existed as high-molecular-weight (HMW) complexes that were resistant to protease degradation. The bactericidal HMW complexes were visualized on non-denaturing gels using protein- and polysaccharide-staining reagents, thereby indicating that the HMW complexes are composed of proteins and polysaccharides. Strongly stained M4B lumen with Periodic acid-Schiff (PAS) reagent in M4B paraffin sections confirmed HMW complexes with polysaccharide components. Furthermore, M4B smears stained with Periodic acid-Schiff revealed the presence of polysaccharide fibers. Therefore, we propose a key digestive mechanism of M4B: bacteriolytic fibers, polysaccharide fibers associated with digestive enzymes such as cathepsin L, specialized for Burkholderia symbionts in Riptortus gut symbiosis.
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Affiliation(s)
- Junbeom Lee
- Metabolomics Research Center for Functional Materials, Kyungsung University, Busan 48434, South Korea
| | - Bohyun Jeong
- Department of Microbiology, Kosin University College of Medicine, Busan 49267, South Korea
| | - Jeongtae Kim
- Department of Anatomy, Kosin University College of Medicine, Busan 49267, South Korea
| | - Jae H Cho
- Host Defense Protein Laboratory, College of Pharmacy, Pusan National University, Busan 46241, South Korea
| | - Jin H Byeon
- Host Defense Protein Laboratory, College of Pharmacy, Pusan National University, Busan 46241, South Korea
| | - Bok L Lee
- Host Defense Protein Laboratory, College of Pharmacy, Pusan National University, Busan 46241, South Korea
| | - Jiyeun K Kim
- Department of Microbiology, Kosin University College of Medicine, Busan 49267, South Korea
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Jouan R, Lextrait G, Lachat J, Yokota A, Cossard R, Naquin D, Timchenko T, Kikuchi Y, Ohbayashi T, Mergaert P. Transposon sequencing reveals the essential gene set and genes enabling gut symbiosis in the insect symbiont Caballeronia insecticola. ISME COMMUNICATIONS 2024; 4:ycad001. [PMID: 38282642 PMCID: PMC10809759 DOI: 10.1093/ismeco/ycad001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 10/10/2023] [Accepted: 11/03/2023] [Indexed: 01/30/2024]
Abstract
Caballeronia insecticola is a bacterium belonging to the Burkholderia genus sensu lato, which is able to colonize multiple environments like soils and the gut of the bean bug Riptortus pedestris. We constructed a saturated Himar1 mariner transposon library and revealed by transposon-sequencing that 498 protein-coding genes constitute the essential genome of Caballeronia insecticola for growth in free-living conditions. By comparing essential gene sets of Caballeronia insecticola and seven related Burkholderia s.l. strains, only 120 common genes were identified, indicating that a large part of the essential genome is strain-specific. In order to reproduce specific nutritional conditions that are present in the gut of Riptortus pedestris, we grew the mutant library in minimal media supplemented with candidate gut nutrients and identified several condition-dependent fitness-defect genes by transposon-sequencing. To validate the robustness of the approach, insertion mutants in six fitness genes were constructed and their growth deficiency in media supplemented with the corresponding nutrient was confirmed. The mutants were further tested for their efficiency in Riptortus pedestris gut colonization, confirming that gluconeogenic carbon sources, taurine and inositol, are nutrients consumed by the symbiont in the gut. Thus, our study provides insights about specific contributions provided by the insect host to the bacterial symbiont.
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Grants
- JSPS Research Fellowship for Young Scientists, Japan
- Ministry of Education, Culture, Sports, Science, and Technology (MEXT), Japan
- Ministry of Higher Education, Research, and Innovation, France
- CNRS International Research Project, France
- JSPS-CNRS Bilateral Open Partnership Joint Research Project, France-Japan
- Agence Nationale de la Recherche, France
- Saclay Plant Sciences-SPS
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Affiliation(s)
- Romain Jouan
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Gaëlle Lextrait
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Joy Lachat
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Aya Yokota
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Raynald Cossard
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Delphine Naquin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Tatiana Timchenko
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Yoshitomo Kikuchi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Hokkaido Center, Sapporo 062-8517, Japan
| | - Tsubasa Ohbayashi
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
- Institute for Agro-Environmental Sciences, National Agriculture and Food Research Organization (NARO), Tsukuba 305-8604, Japan
| | - Peter Mergaert
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
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9
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González Porras MÁ, Pons I, García-Lozano M, Jagdale S, Emmerich C, Weiss B, Salem H. Extracellular symbiont colonizes insect during embryo development. ISME COMMUNICATIONS 2024; 4:ycae005. [PMID: 38439943 PMCID: PMC10910848 DOI: 10.1093/ismeco/ycae005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/11/2024] [Accepted: 01/17/2024] [Indexed: 03/06/2024]
Abstract
Insects typically acquire their beneficial microbes early in development. Endosymbionts housed intracellularly are commonly integrated during oogenesis or embryogenesis, whereas extracellular microbes are only known to be acquired after hatching by immature instars such as larvae or nymphs. Here, however, we report on an extracellular symbiont that colonizes its host during embryo development. Tortoise beetles (Chrysomelidae: Cassidinae) host their digestive bacterial symbiont Stammera extracellularly within foregut symbiotic organs and in ovary-associated glands to ensure its vertical transmission. We outline the initial stages of symbiont colonization and observe that although the foregut symbiotic organs develop 3 days prior to larval emergence, they remain empty until the final 24 h of embryo development. Infection by Stammera occurs during that timeframe and prior to hatching. By experimentally manipulating symbiont availability to embryos in the egg, we describe a 12-h developmental window governing colonization by Stammera. Symbiotic organs form normally in aposymbiotic larvae, demonstrating that these Stammera-bearing structures develop autonomously. In adults, the foregut symbiotic organs are already colonized following metamorphosis and host a stable Stammera population to facilitate folivory. The ovary-associated glands, however, initially lack Stammera. Symbiont abundance subsequently increases within these transmission organs, thereby ensuring sufficient titers at the onset of oviposition ~29 days following metamorphosis. Collectively, our findings reveal that Stammera colonization precedes larval emergence, where its proliferation is eventually decoupled in adult beetles to match the nutritional and reproductive requirements of its host.
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Affiliation(s)
| | - Inès Pons
- Mutualisms Research Group, Max Planck Institute for Biology, Tübingen 72076, Germany
| | - Marleny García-Lozano
- Mutualisms Research Group, Max Planck Institute for Biology, Tübingen 72076, Germany
| | - Shounak Jagdale
- Mutualisms Research Group, Max Planck Institute for Biology, Tübingen 72076, Germany
| | - Christiane Emmerich
- Mutualisms Research Group, Max Planck Institute for Biology, Tübingen 72076, Germany
| | - Benjamin Weiss
- Department of Insect Symbiosis, Max Planck Institute for Chemical Ecology, Jena 07745, Germany
| | - Hassan Salem
- Mutualisms Research Group, Max Planck Institute for Biology, Tübingen 72076, Germany
- Smithsonian Tropical Research Institute, Panama City 0843-03092, Republic of Panama
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10
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Yang ZW, Luo JY, Men Y, Liu ZH, Zheng ZK, Wang YH, Xie Q. Different roles of host and habitat in determining the microbial communities of plant-feeding true bugs. MICROBIOME 2023; 11:244. [PMID: 37932839 PMCID: PMC10629178 DOI: 10.1186/s40168-023-01702-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 10/17/2023] [Indexed: 11/08/2023]
Abstract
BACKGROUND The true bugs (Heteroptera) occupy nearly all of the known ecological niches of insects. Among them, as a group containing more than 30,000 species, the phytophagous true bugs are making increasing impacts on agricultural and forestry ecosystems. Previous studies proved that symbiotic bacteria play important roles in these insects in fitting various habitats. However, it is still obscure about the evolutionary and ecological patterns of the microorganisms of phytophagous true bugs as a whole with comprehensive taxon sampling. RESULTS Here, in order to explore the symbiotic patterns between plant-feeding true bugs and their symbiotic microorganisms, 209 species belonging to 32 families of 9 superfamilies had been sampled, which covered all the major phytophagous families of true bugs. The symbiotic microbial communities were surveyed by full-length 16S rRNA gene and ITS amplicons respectively for bacteria and fungi using the PacBio platform. We revealed that hosts mainly affect the dominant bacteria of symbiotic microbial communities, while habitats generally influence the subordinate ones. Thereafter, we carried out the ancestral state reconstruction of the dominant bacteria and found that dramatic replacements of dominant bacteria occurred in the early Cretaceous and formed newly stable symbiotic relationships accompanying the radiation of insect families. In contrast, the symbiotic fungi were revealed to be horizontally transmitted, which makes fungal communities distinctive in different habitats but not significantly related to hosts. CONCLUSIONS Host and habitat determine microbial communities of plant-feeding true bugs in different roles. The symbiotic bacterial communities are both shaped by host and habitat but in different ways. Nevertheless, the symbiotic fungal communities are mainly influenced by habitat but not host. These findings shed light on a general framework for future microbiome research of phytophagous insects. Video Abstract.
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Affiliation(s)
- Zi-Wen Yang
- School of Life Sciences, State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, 510275, Guangdong, China
| | - Jiu-Yang Luo
- School of Life Sciences, State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, 510275, Guangdong, China
| | - Yu Men
- School of Life Sciences, Zhaoqing University, Zhaoqing, 526061, China
| | - Zhi-Hui Liu
- School of Life Sciences, State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, 510275, Guangdong, China
| | - Zi-Kai Zheng
- School of Life Sciences, State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, 510275, Guangdong, China
| | - Yan-Hui Wang
- School of Life Sciences, State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, 510275, Guangdong, China
| | - Qiang Xie
- School of Life Sciences, State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, 510275, Guangdong, China.
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11
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Lange C, Boyer S, Bezemer TM, Lefort MC, Dhami MK, Biggs E, Groenteman R, Fowler SV, Paynter Q, Verdecia Mogena AM, Kaltenpoth M. Impact of intraspecific variation in insect microbiomes on host phenotype and evolution. THE ISME JOURNAL 2023; 17:1798-1807. [PMID: 37660231 PMCID: PMC10579242 DOI: 10.1038/s41396-023-01500-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 08/20/2023] [Accepted: 08/22/2023] [Indexed: 09/04/2023]
Abstract
Microbes can be an important source of phenotypic plasticity in insects. Insect physiology, behaviour, and ecology are influenced by individual variation in the microbial communities held within the insect gut, reproductive organs, bacteriome, and other tissues. It is becoming increasingly clear how important the insect microbiome is for insect fitness, expansion into novel ecological niches, and novel environments. These investigations have garnered heightened interest recently, yet a comprehensive understanding of how intraspecific variation in the assembly and function of these insect-associated microbial communities can shape the plasticity of insects is still lacking. Most research focuses on the core microbiome associated with a species of interest and ignores intraspecific variation. We argue that microbiome variation among insects can be an important driver of evolution, and we provide examples showing how such variation can influence fitness and health of insects, insect invasions, their persistence in new environments, and their responses to global environmental changes. A and B are two stages of an individual or a population of the same species. The drivers lead to a shift in the insect associated microbial community, which has consequences for the host. The complex interplay of those consequences affects insect adaptation and evolution and influences insect population resilience or invasion.
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Affiliation(s)
- Claudia Lange
- Manaaki Whenua Landcare Research, Lincoln, New Zealand.
| | - Stéphane Boyer
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261 CNRS - Université de Tours, Tours, France
| | - T Martijn Bezemer
- Above-Belowground Interactions Group, Institute of Biology, Leiden University, Leiden, The Netherlands
| | | | | | - Eva Biggs
- Manaaki Whenua Landcare Research, Lincoln, New Zealand
| | | | | | | | | | - Martin Kaltenpoth
- Department of Insect Symbiosis, Max Planck Institute for Chemical Ecology, Jena, Germany
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12
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Qin M, Jiang L, Qiao G, Chen J. Phylosymbiosis: The Eco-Evolutionary Pattern of Insect-Symbiont Interactions. Int J Mol Sci 2023; 24:15836. [PMID: 37958817 PMCID: PMC10650905 DOI: 10.3390/ijms242115836] [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: 09/28/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 11/15/2023] Open
Abstract
Insects harbor diverse assemblages of bacterial and fungal symbionts, which play crucial roles in host life history. Insects and their various symbionts represent a good model for studying host-microbe interactions. Phylosymbiosis is used to describe an eco-evolutionary pattern, providing a new cross-system trend in the research of host-associated microbiota. The phylosymbiosis pattern is characterized by a significant positive correlation between the host phylogeny and microbial community dissimilarities. Although host-symbiont interactions have been demonstrated in many insect groups, our knowledge of the prevalence and mechanisms of phylosymbiosis in insects is still limited. Here, we provide an order-by-order summary of the phylosymbiosis patterns in insects, including Blattodea, Coleoptera, Diptera, Hemiptera, Hymenoptera, and Lepidoptera. Then, we highlight the potential contributions of stochastic effects, evolutionary processes, and ecological filtering in shaping phylosymbiotic microbiota. Phylosymbiosis in insects can arise from a combination of stochastic and deterministic mechanisms, such as the dispersal limitations of microbes, codiversification between symbionts and hosts, and the filtering of phylogenetically conserved host traits (incl., host immune system, diet, and physiological characteristics).
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Affiliation(s)
- Man Qin
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; (M.Q.); (L.J.)
| | - Liyun Jiang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; (M.Q.); (L.J.)
| | - Gexia Qiao
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; (M.Q.); (L.J.)
- 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; (M.Q.); (L.J.)
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13
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Villa SM, Chen JZ, Kwong Z, Acosta A, Vega NM, Gerardo NM. Specialized acquisition behaviors maintain reliable environmental transmission in an insect-microbial mutualism. Curr Biol 2023:S0960-9822(23)00724-8. [PMID: 37385254 DOI: 10.1016/j.cub.2023.05.062] [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: 12/05/2022] [Revised: 04/07/2023] [Accepted: 05/25/2023] [Indexed: 07/01/2023]
Abstract
Understanding how horizontally transmitted mutualisms are maintained is a major focus of symbiosis research.1,2,3,4 Unlike vertical transmission, hosts that rely on horizontal transmission produce symbiont-free offspring that must find and acquire their beneficial microbes from the environment. This transmission strategy is inherently risky since hosts may not obtain the right symbiont every generation. Despite these potential costs, horizontal transmission underlies stable mutualisms involving a large diversity of both plants and animals.5,6,7,8,9 One largely unexplored way horizontal transmission is maintained is for hosts to evolve sophisticated mechanisms to consistently find and acquire specific symbionts from the environment. Here, we examine this possibility in the squash bug Anasa tristis, an insect pest that requires bacterial symbionts in the genus Caballeronia10 for survival and development.11 We conduct a series of behavioral and transmission experiments that track strain-level transmission in vivo among individuals in real-time. We demonstrate that nymphs can accurately find feces from adult bugs in both the presence and absence of those adults. Once nymphs locate the feces, they deploy feeding behavior that results in nearly perfect symbiont acquisition success. We further demonstrate that nymphs can locate and feed on isolated, cultured symbionts in the absence of feces. Finally, we show this acquisition behavior is highly host specific. Taken together, our data describe not only the evolution of a reliable horizontal transmission strategy, but also a potential mechanism that drives patterns of species-specific microbial communities among closely related, sympatric host species.
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Affiliation(s)
- Scott M Villa
- Department of Biology, Emory University, 1510 Clifton Rd., Atlanta, GA 30322, USA; Department of Biology, Davidson College, 209 Ridge Rd., Davidson, NC 28035, USA.
| | - Jason Z Chen
- Department of Biology, Emory University, 1510 Clifton Rd., Atlanta, GA 30322, USA
| | - Zeeyong Kwong
- Department of Biology, Emory University, 1510 Clifton Rd., Atlanta, GA 30322, USA
| | - Alice Acosta
- Department of Biology, Emory University, 1510 Clifton Rd., Atlanta, GA 30322, USA
| | - Nicole M Vega
- Department of Biology, Emory University, 1510 Clifton Rd., Atlanta, GA 30322, USA
| | - Nicole M Gerardo
- Department of Biology, Emory University, 1510 Clifton Rd., Atlanta, GA 30322, USA
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14
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Dodge R, Jones EW, Zhu H, Obadia B, Martinez DJ, Wang C, Aranda-Díaz A, Aumiller K, Liu Z, Voltolini M, Brodie EL, Huang KC, Carlson JM, Sivak DA, Spradling AC, Ludington WB. A symbiotic physical niche in Drosophila melanogaster regulates stable association of a multi-species gut microbiota. Nat Commun 2023; 14:1557. [PMID: 36944617 PMCID: PMC10030875 DOI: 10.1038/s41467-023-36942-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 02/22/2023] [Indexed: 03/23/2023] Open
Abstract
The gut is continuously invaded by diverse bacteria from the diet and the environment, yet microbiome composition is relatively stable over time for host species ranging from mammals to insects, suggesting host-specific factors may selectively maintain key species of bacteria. To investigate host specificity, we used gnotobiotic Drosophila, microbial pulse-chase protocols, and microscopy to investigate the stability of different strains of bacteria in the fly gut. We show that a host-constructed physical niche in the foregut selectively binds bacteria with strain-level specificity, stabilizing their colonization. Primary colonizers saturate the niche and exclude secondary colonizers of the same strain, but initial colonization by Lactobacillus species physically remodels the niche through production of a glycan-rich secretion to favor secondary colonization by unrelated commensals in the Acetobacter genus. Our results provide a mechanistic framework for understanding the establishment and stability of a multi-species intestinal microbiome.
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Affiliation(s)
- Ren Dodge
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD, 21218, USA
| | - Eric W Jones
- Department of Physics, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
- Department of Physics, University of California, Santa Barbara, CA, 93106, USA
| | - Haolong Zhu
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD, 21218, USA
- Department of Biology, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Benjamin Obadia
- Molecular and Cell Biology Department, University of California, Berkeley, CA, 94720, USA
| | - Daniel J Martinez
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD, 21218, USA
| | - Chenhui Wang
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD, 21218, USA
- Howard Hughes Medical Institute, Baltimore, MD, 21218, USA
| | - Andrés Aranda-Díaz
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Kevin Aumiller
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD, 21218, USA
- Department of Biology, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Zhexian Liu
- Department of Biology, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Marco Voltolini
- Lawrence Berkeley National Lab, Berkeley, CA, 94720, USA
- Dipartimento di Scienze della Terra, Università degli Studi di Milano, Milano, Italy
| | - Eoin L Brodie
- Lawrence Berkeley National Lab, Berkeley, CA, 94720, USA
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, 94305, USA
- Chan Zuckerberg Biohub, San Francisco, CA, 94158, USA
| | - Jean M Carlson
- Department of Physics, University of California, Santa Barbara, CA, 93106, USA
| | - David A Sivak
- Department of Physics, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
| | - Allan C Spradling
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD, 21218, USA
- Department of Biology, Johns Hopkins University, Baltimore, MD, 21218, USA
- Howard Hughes Medical Institute, Baltimore, MD, 21218, USA
| | - William B Ludington
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD, 21218, USA.
- Department of Biology, Johns Hopkins University, Baltimore, MD, 21218, USA.
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15
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Proteolytic Activity of DegP Is Required for the Burkholderia Symbiont To Persist in Its Host Bean Bug. Microbiol Spectr 2023; 11:e0433022. [PMID: 36511662 PMCID: PMC9927360 DOI: 10.1128/spectrum.04330-22] [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] [Indexed: 12/15/2022] Open
Abstract
Symbiosis requires the adaptation of symbiotic bacteria to the host environment. Symbiotic factors for bacterial adaptation have been studied in various experimental models, including the Burkholderia-bean bug symbiosis model. Previously identified symbiotic factors of Burkholderia symbionts of bean bugs provided insight into the host environment being stressful to the symbionts. Because DegP, which functions as both a protease and a chaperone, supports bacterial growth under various stressful conditions, we hypothesized that DegP might be a novel symbiotic factor of Burkholderia symbionts in the symbiotic association with bean bugs. The expression level of degP was highly elevated in symbiotic Burkholderia cells in comparison with cultured cells. When the degP-deficient strain competed for symbiotic association against the wild-type strain, the ΔdegP strain showed no symbiotic competitiveness. In vivo monoinfection with the ΔdegP strain revealed a lower symbiont titer in the symbiotic organ than that of the wild-type strain, indicating that the ΔdegP strain failed to persist in the host. In in vitro assays, the ΔdegP strain showed susceptibility to heat and high-salt stressors and a decreased level of biofilm formation. To further determine the role of the proteolytic activity of DegP in symbiosis, we generated missense mutant DegPS248A exhibiting a defect in protease activity only. The ΔdegP strain complemented with degPS248A showed in vitro characteristics similar to those of the ΔdegP strain and failed to persist in the symbiotic organ. Together, the results of our study demonstrated that the proteolytic activity of DegP, which is involved in the stress resistance and biofilm formation of the Burkholderia symbiont, plays an essential role in symbiotic persistence in the host bean bug. IMPORTANCE Bacterial DegP has dual functions as a protease and a chaperone and supports bacterial growth under stressful conditions. In symbioses involving bacteria, bacterial symbionts encounter various stressors and may need functional DegP for symbiotic association with the host. Using the Burkholderia-bean bug symbiosis model, which is a useful model for identifying bacterial symbiotic factors, we demonstrated that DegP is indeed a symbiotic factor of Burkholderia persistence in its host bean bug. In vitro experiments to understand the symbiotic mechanisms of degP revealed that degP confers resistance to heat and high-salt stresses. In addition, degP supports biofilm formation, which is a previously identified persistence factor of the Burkholderia symbiont. Furthermore, using a missense mutation in a protease catalytic site of degP, we specifically elucidated that the proteolytic activity of degP plays essential roles in stress resistance, biofilm formation, and, thus, symbiotic persistence in the host bean bug.
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16
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Crosstalk between the microbiota and insect postembryonic development. Trends Microbiol 2023; 31:181-196. [PMID: 36167769 DOI: 10.1016/j.tim.2022.08.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 06/20/2022] [Accepted: 08/25/2022] [Indexed: 01/27/2023]
Abstract
Insect sequential development evolves from a simple molt towards complete metamorphosis. Like any multicellular host, insects interact with a complex microbiota. In this review, factors driving the microbiota dynamics were pointed out along their development. Special focus was put on tissue renewal, shift in insect ecology, and microbial interactions. Conversely, how the microbiota modulates its host development through nutrient acquisition, hormonal control, and cellular or tissue differentiation was exemplified. Such modifications might have long-term carry-over effects on insect physiology. Finally, remarkable microbe-driven control of insect behaviors along their life cycle was highlighted. Increasing knowledge of those interactions might offer new insights on how insects respond to their environment as well as perspectives on pest- or vector-control strategies.
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17
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Jang S, Matsuura Y, Ishigami K, Mergaert P, Kikuchi Y. Symbiont coordinates stem cell proliferation, apoptosis, and morphogenesis of gut symbiotic organ in the stinkbug- Caballeronia symbiosis. Front Physiol 2023; 13:1071987. [PMID: 36685208 PMCID: PMC9846216 DOI: 10.3389/fphys.2022.1071987] [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: 10/17/2022] [Accepted: 12/16/2022] [Indexed: 01/05/2023] Open
Abstract
The bean bug Riptortus pedestris obtains a specific bacterial symbiont, Caballeronia insecticola (Burkholderia insecticola), from the environmental soil and harbors it in the posterior midgut region that is composed of hundreds of crypts. While newly hatched aposymbiotic insects possess primordial midgut crypts with little or no lumen, colonization of C. insecticola triggers swift development of the symbiotic organ, forming enlarged and opened crypts, and the symbiont subsequently fills the luminal cavities of those mature crypts. The cellular processes of crypt development triggered by C. insecticola colonization are poorly understood. Here we identified a fundamental mechanism of the symbiont-mediated midgut development by investigating cell cycles of intestinal epithelial cells. Intestinal stem cells of the bean bug are located and proliferate at the crypt base. Differentiated enterocytes migrate upward along the epithelial cell layer of the crypt as the midgut develops, induction of apoptosis in enterocytes primarily occurred on the tip side of the crypts, and apoptotic cells then eventually were shed from the crypts into the hemolymph. The proliferation rate of the stem cells at the base of the crypts was low while a high apoptotic rate was observed at the crypt tip in aposymbiotic insects, resulting in undeveloped short crypts. On the contrary, the gut-colonizing C. insecticola promoted the proliferation of the stem cells at the base of crypts and simultaneously inhibited apoptosis at the tip of crypts, resulting in a net growth of the crypts and the generation of a crypt lumen that becomes colonized by the bacterial symbiont. These results demonstrated that the Caballeronia symbiont colonization induces the development of the midgut crypts via finely regulating the enterocyte cell cycles, enabling it to stably and abundantly colonize the generated spacious crypts of the bean bug host.
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Affiliation(s)
- Seonghan Jang
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Hokkaido Center, Sapporo, Japan,Division of Life Sciences, Korea Polar Research Institute, Incheon, South Korea,*Correspondence: Seonghan Jang, ; Yoshitomo Kikuchi,
| | - Yu Matsuura
- Tropical Biosphere Research Center, University of the Ryukyus, Nishihara, Okinawa, Japan
| | - Kota Ishigami
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Hokkaido Center, Sapporo, Japan,Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
| | - Peter Mergaert
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Yoshitomo Kikuchi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Hokkaido Center, Sapporo, Japan,Graduate School of Agriculture, Hokkaido University, Sapporo, Japan,*Correspondence: Seonghan Jang, ; Yoshitomo Kikuchi,
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18
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Ganesan R, Wierz JC, Kaltenpoth M, Flórez LV. How It All Begins: Bacterial Factors Mediating the Colonization of Invertebrate Hosts by Beneficial Symbionts. Microbiol Mol Biol Rev 2022; 86:e0012621. [PMID: 36301103 PMCID: PMC9769632 DOI: 10.1128/mmbr.00126-21] [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] [Indexed: 01/01/2023] Open
Abstract
Beneficial associations with bacteria are widespread across animals, spanning a range of symbiont localizations, transmission routes, and functions. While some of these associations have evolved into obligate relationships with permanent symbiont localization within the host, the majority require colonization of every host generation from the environment or via maternal provisions. Across the broad diversity of host species and tissue types that beneficial bacteria can colonize, there are some highly specialized strategies for establishment yet also some common patterns in the molecular basis of colonization. This review focuses on the mechanisms underlying the early stage of beneficial bacterium-invertebrate associations, from initial contact to the establishment of the symbionts in a specific location of the host's body. We first reflect on general selective pressures that can drive the transition from a free-living to a host-associated lifestyle in bacteria. We then cover bacterial molecular factors for colonization in symbioses from both model and nonmodel invertebrate systems where these have been studied, including terrestrial and aquatic host taxa. Finally, we discuss how interactions between multiple colonizing bacteria and priority effects can influence colonization. Taking the bacterial perspective, we emphasize the importance of developing new experimentally tractable systems to derive general insights into the ecological factors and molecular adaptations underlying the origin and establishment of beneficial symbioses in animals.
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Affiliation(s)
- Ramya Ganesan
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
- Department of Insect Symbiosis, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Jürgen C. Wierz
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
- Department of Insect Symbiosis, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Martin Kaltenpoth
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
- Department of Insect Symbiosis, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Laura V. Flórez
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
- Department of Plant and Environmental Sciences, Section for Organismal Biology, University of Copenhagen, Copenhagen, Denmark
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19
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Vigneron A, Kaltenpoth M. Symbiosis: Creating a tractable intracellular insect-microbe association. Curr Biol 2022; 32:R943-R946. [PMID: 36167040 DOI: 10.1016/j.cub.2022.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Endosymbioses are widespread among insects and have far-reaching implications for their hosts' ecology and evolution. However, the molecular underpinnings of symbiosis remain largely obscure. In a new study, Su et al. successfully established a transmissible synthetic symbiosis, opening up exciting new opportunities to explore the initial dynamics of endosymbiotic interactions.
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Affiliation(s)
- Aurélien Vigneron
- Department of Insect Symbiosis, Max Planck Institute for Chemical Ecology, Jena 07745, Germany.
| | - Martin Kaltenpoth
- Department of Insect Symbiosis, Max Planck Institute for Chemical Ecology, Jena 07745, Germany.
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20
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Abstract
Hereditary symbioses have the potential to drive transgenerational effects, yet the mechanisms responsible for transmission of heritable plant symbionts are still poorly understood. The leaf symbiosis between Dioscorea sansibarensis and the bacterium Orrella dioscoreae offers an appealing model system to study how heritable bacteria are transmitted to the next generation. Here, we demonstrate that inoculation of apical buds with a bacterial suspension is sufficient to colonize newly formed leaves and propagules, and to ensure transmission to the next plant generation. Flagellar motility is not required for movement inside the plant but is important for the colonization of new hosts. Further, tissue-specific regulation of putative symbiotic functions highlights the presence of two distinct subpopulations of bacteria in the leaf gland and at the shoot meristem. We propose that bacteria in the leaf gland dedicate resources to symbiotic functions, while dividing bacteria in the shoot tip ensure successful colonization of meristematic tissue, glands, and propagules. Compartmentalization of intrahost populations together with tissue-specific regulation may serve as a robust mechanism for the maintenance of mutualism in leaf symbiosis.
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21
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Ohbayashi T, Cossard R, Lextrait G, Hosokawa T, Lesieur V, Takeshita K, Tago K, Mergaert P, Kikuchi Y. Intercontinental Diversity of Caballeronia Gut Symbionts in the Conifer Pest Bug Leptoglossus occidentalis. Microbes Environ 2022; 37. [PMID: 35965097 PMCID: PMC9530724 DOI: 10.1264/jsme2.me22042] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Many stinkbugs in the superfamily Coreoidea (Hemiptera: Heteroptera) develop crypts in the posterior midgut, harboring Caballeronia (Burkholderia) symbionts. These symbionts form a monophyletic group in Burkholderia sensu lato, called the “stinkbug-associated beneficial and environmental (SBE)” group, recently reclassified as the new genus Caballeronia. SBE symbionts are separated into the subclades SBE-α and SBE-β. Previous studies suggested a regional effect on the symbiont infection pattern; Japanese and American bug species are more likely to be associated with SBE-α, while European bug species are almost exclusively associated with SBE-β. However, since only a few insect species have been investigated, it remains unclear whether region-specific infection is general. We herein investigated Caballeronia gut symbionts in diverse Japanese, European, and North American populations of a cosmopolitan species, the Western conifer seed bug Leptoglossus occidentalis (Coreoidea: Coreidae). A molecular phylogenetic analysis of the 16S rRNA gene demonstrated that SBE-β was the most dominant in all populations. Notably, SBE-α was rarely detected in any region, while a third clade, the “Coreoidea clade” occupied one fourth of the tested populations. Although aposymbiotic bugs showed high mortality, SBE-α- and SBE-β-inoculated insects both showed high survival rates; however, a competition assay demonstrated that SBE-β outcompeted SBE-α in the midgut crypts of L. occidentalis. These results strongly suggest that symbiont specificity in the Leptoglossus-Caballeronia symbiotic association is influenced by the host rather than geography, while the geographic distribution of symbionts may be more important in other bugs.
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Affiliation(s)
- Tsubasa Ohbayashi
- Institute for Agro-Environmental Sciences, National Agriculture and Food Research Organization (NARO).,Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC)
| | - Raynald Cossard
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC)
| | - Gaëlle Lextrait
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC)
| | | | | | | | - Kanako Tago
- Institute for Agro-Environmental Sciences, National Agriculture and Food Research Organization (NARO)
| | - Peter Mergaert
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC)
| | - Yoshitomo Kikuchi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Hokkaido Center.,Graduate School of Agriculture, Hokkaido University
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22
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Pronk LJU, Bakker PAHM, Keel C, Maurhofer M, Flury P. The secret life of plant-beneficial rhizosphere bacteria: insects as alternative hosts. Environ Microbiol 2022; 24:3273-3289. [PMID: 35315557 PMCID: PMC9542179 DOI: 10.1111/1462-2920.15968] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 03/03/2022] [Accepted: 03/04/2022] [Indexed: 12/15/2022]
Abstract
Root-colonizing bacteria have been intensively investigated for their intimate relationship with plants and their manifold plant-beneficial activities. They can inhibit growth and activity of pathogens or induce defence responses. In recent years, evidence has emerged that several plant-beneficial rhizosphere bacteria do not only associate with plants but also with insects. Their relationships with insects range from pathogenic to mutualistic and some rhizobacteria can use insects as vectors for dispersal to new host plants. Thus, the interactions of these bacteria with their environment are even more complex than previously thought and can extend far beyond the rhizosphere. The discovery of this secret life of rhizobacteria represents an exciting new field of research that should link the fields of plant-microbe and insect-microbe interactions. In this review, we provide examples of plant-beneficial rhizosphere bacteria that use insects as alternative hosts, and of potentially rhizosphere-competent insect symbionts. We discuss the bacterial traits that may enable a host-switch between plants and insects and further set the multi-host lifestyle of rhizobacteria into an evolutionary and ecological context. Finally, we identify important open research questions and discuss perspectives on the use of these rhizobacteria in agriculture.
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Affiliation(s)
| | | | - Christoph Keel
- Department of Fundamental MicrobiologyUniversity of LausanneLausanneSwitzerland
| | - Monika Maurhofer
- Plant Pathology, Institute of Integrative BiologyETH ZürichZürichSwitzerland
| | - Pascale Flury
- Crop Protection – Phytopathology, Department of Crop SciencesResearch Institute of Organic Agriculture FiBLFrickSwitzerland
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23
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Lynch JB, James N, McFall-Ngai M, Ruby EG, Shin S, Takagi D. Transitioning to confined spaces impacts bacterial swimming and escape response. Biophys J 2022; 121:2653-2662. [PMID: 35398019 PMCID: PMC9300662 DOI: 10.1016/j.bpj.2022.04.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/28/2021] [Accepted: 04/05/2022] [Indexed: 11/02/2022] Open
Abstract
Symbiotic bacteria often navigate complex environments before colonizing privileged sites in their host organism. Chemical gradients are known to facilitate directional taxis of these bacteria, guiding them toward their eventual destination. However, less is known about the role of physical features in shaping the path the bacteria take and defining how they traverse a given space. The flagellated marine bacterium Vibrio fischeri, which forms a binary symbiosis with the Hawaiian bobtail squid, Euprymna scolopes, must navigate tight physical confinement during colonization, squeezing through a tissue bottleneck constricting to ∼2 μm in width on the way to its eventual home. Using microfluidic in vitro experiments, we discovered that V. fischeri cells alter their behavior upon entry into confined space, straightening their swimming paths and promoting escape from confinement. Using a computational model, we attributed this escape response to two factors: reduced directional fluctuation and a refractory period between reversals. Additional experiments in asymmetric capillary tubes confirmed that V. fischeri quickly escape from confined ends, even when drawn into the ends by chemoattraction. This avoidance was apparent down to a limit of confinement approaching the diameter of the cell itself, resulting in a balance between chemoattraction and evasion of physical confinement. Our findings demonstrate that nontrivial distributions of swimming bacteria can emerge from simple physical gradients in the level of confinement. Tight spaces may serve as an additional, crucial cue for bacteria while they navigate complex environments to enter specific habitats.
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Affiliation(s)
- Jonathan B Lynch
- Pacific Biosciences Research Center, University of Hawai'i at Mānoa, Honolulu, Hawai'i.
| | - Nicholas James
- Department of Cell and Molecular Biology, University of Hawai'i at Mānoa, Honolulu, Hawai'i
| | - Margaret McFall-Ngai
- Pacific Biosciences Research Center, University of Hawai'i at Mānoa, Honolulu, Hawai'i
| | - Edward G Ruby
- Pacific Biosciences Research Center, University of Hawai'i at Mānoa, Honolulu, Hawai'i
| | - Sangwoo Shin
- Department of Mechanical Engineering, University of Hawai'i at Mānoa, Honolulu, Hawai'i; Department of Mechanical and Aerospace Engineering, University at Buffalo, Buffalo, New York
| | - Daisuke Takagi
- Pacific Biosciences Research Center, University of Hawai'i at Mānoa, Honolulu, Hawai'i; Department of Mechanical Engineering, University of Hawai'i at Mānoa, Honolulu, Hawai'i; Department of Mathematics, University of Hawai'i at Mānoa, Honolulu, Hawai'i
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24
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Fronk DC, Sachs JL. Symbiotic organs: the nexus of host-microbe evolution. Trends Ecol Evol 2022; 37:599-610. [PMID: 35393155 DOI: 10.1016/j.tree.2022.02.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 02/14/2022] [Accepted: 02/28/2022] [Indexed: 02/07/2023]
Abstract
Diverse plants and animals have evolved specialized structures to filter and house beneficial microbes. These symbiotic organs form crucial points of exchange between host and symbiont, are often shaped by both partners, and exhibit features that facilitate a suite of microbial services. While symbiotic organs exhibit varied function, morphology, and developmental plasticity, they share core features linked to the evolutionary maintenance of beneficial symbiosis. Moreover, these organs can have a significant role in altering the demographic forces that shape microbial genomes, driving population bottlenecks and horizontal gene transfer (HGT). To advance our understanding of these 'joint phenotypes' across varied systems, future research must consider the emergent forces that can shape symbiotic organs, including fitness feedbacks and conflicts between interacting genomes.
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Affiliation(s)
- David C Fronk
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA 92521, USA
| | - Joel L Sachs
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA 92521, USA; Department of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA; Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA.
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25
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Stillson PT, Baltrus DA, Ravenscraft A. Prevalence of an Insect-Associated Genomic Region in Environmentally Acquired Burkholderiaceae Symbionts. Appl Environ Microbiol 2022; 88:e0250221. [PMID: 35435710 PMCID: PMC9088363 DOI: 10.1128/aem.02502-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 03/25/2022] [Indexed: 11/20/2022] Open
Abstract
Microbial symbionts are critical for the development and survival of many eukaryotes. Recent research suggests that the genes enabling these relationships can be localized in horizontally transferred regions of microbial genomes termed "symbiotic islands." Recently, a putative symbiotic island was found that may facilitate symbioses between true bugs and numerous Burkholderia species, based on analysis of five Burkholderia symbionts. We expanded on this work by exploring the putative island's prevalence, origin, and association with colonization across the bacterial family Burkholderiaceae. We performed a broad comparative analysis of 229 Burkholderiaceae genomes, including 8 new genomes of insect- or soil-associated Burkholderia sequenced for this study. We detected the region in 23% of the genomes; these were located solely within two Burkholderia clades. Our analyses suggested that the contiguous region arose at the common ancestor of plant- and insect-associated Burkholderia clades, but the genes themselves are ancestral. Although the region was initially discovered on plasmids and we did detect two likely instances of horizontal transfer within Burkholderia, we found that the region is almost always localized to a chromosome and does not possess any of the mobility elements that typify genomic islands. Finally, to attempt to deduce the region's function, we combined our data with information on several strains' abilities to colonize the insect's symbiotic organ. Although the region was associated with improved colonization of the host, this relationship was confounded with, and likely driven by, Burkholderia clade membership. These findings advance our understanding of the genomic underpinnings of a widespread insect-microbe symbiosis. IMPORTANCE Many plants and animals form intricate associations with bacteria. These pairings can be mediated by genomic islands, contiguous regions containing numerous genes with cohesive functionality. Pathogen-associated islands are well described, but recent evidence suggests that mutualistic islands, which benefit both host and symbiont, may also be common. Recently, a putative symbiosis island was found in Burkholderia symbionts of insects. We determined that this genomic region is located in only two clades of Burkholderia (the plant- and insect-associated species) and that although it has undergone horizontal transfer, it is most likely a symbiosis-associated region rather than a true island. This region is associated with improved host colonization, although this is may be due to specific Burkholderia clades' abilities to colonize rather than presence of the region. By studying the genomic basis of the insect-Burkholderia symbiosis, we can better understand how mutualisms evolve in animals.
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Affiliation(s)
- Patrick T. Stillson
- Department of Biology, University of Texas at Arlington, Arlington, Texas, USA
| | - David A. Baltrus
- School of Plant Sciences, University of Arizona, Tucson, Arizona, USA
| | - Alison Ravenscraft
- Department of Biology, University of Texas at Arlington, Arlington, Texas, USA
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26
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Pons I, González Porras MÁ, Breitenbach N, Berger J, Hipp K, Salem H. For the road: calibrated maternal investment in light of extracellular symbiont transmission. Proc Biol Sci 2022; 289:20220386. [PMID: 35473381 PMCID: PMC9043728 DOI: 10.1098/rspb.2022.0386] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Faithful transmission of beneficial symbionts is critical for the persistence of mutualisms. Many insect groups rely on extracellular routes that require microbial symbionts to survive outside the host during transfer. However, given a prolonged aposymbiotic phase in offspring, how do mothers mitigate the risk of symbiont loss due to unsuccessful transmission? Here, we investigated symbiont regulation and reacquisition during extracellular transfer in the tortoise beetle, Chelymorpha alternans (Coleoptera: Cassidinae). Like many cassidines, C. alternans relies on egg caplets to vertically propagate its obligate symbiont Candidatus Stammera capleta. On average, each caplet is supplied with 12 symbiont-bearing spheres where Stammera is embedded. We observe limited deviation (±2.3) in the number of spheres allocated to each caplet, indicating strict maternal control over symbiont supply. Larvae acquire Stammera 1 day prior to eclosion but are unable to do so after hatching, suggesting that a specific developmental window governs symbiont uptake. Experimentally manipulating the number of spheres available to each egg revealed that a single sphere is sufficient to ensure successful colonization by Stammera relative to the 12 typically packaged within a caplet. Collectively, our findings shed light on a tightly regulated symbiont transmission cycle optimized to ensure extracellular transfer.
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Affiliation(s)
- Inès Pons
- Mutualisms Research Group, Max Planck Institute for Biology, Tübingen 72076, Germany
| | | | - Noa Breitenbach
- Mutualisms Research Group, Max Planck Institute for Biology, Tübingen 72076, Germany
| | - Jürgen Berger
- Electron Microscopy Facility, Max Planck Institute for Biology, Tübingen 72076, Germany
| | - Katharina Hipp
- Electron Microscopy Facility, Max Planck Institute for Biology, Tübingen 72076, Germany
| | - Hassan Salem
- Mutualisms Research Group, Max Planck Institute for Biology, Tübingen 72076, Germany
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27
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Bacterial Quorum-Sensing Regulation Induces Morphological Change in a Key Host Tissue during the Euprymna scolopes-Vibrio fischeri Symbiosis. mBio 2021; 12:e0240221. [PMID: 34579565 PMCID: PMC8546586 DOI: 10.1128/mbio.02402-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Microbes colonize the apical surfaces of polarized epithelia in nearly all animal taxa. In one example, the luminous bacterium Vibrio fischeri enters, grows to a dense population within, and persists for months inside, the light-emitting organ of the squid Euprymna scolopes. Crucial to the symbiont's success after entry is the ability to trigger the constriction of a host tissue region (the "bottleneck") at the entrance to the colonization site. Bottleneck constriction begins at about the same time as bioluminescence, which is induced in V. fischeri through an autoinduction process called quorum sensing. Here, we asked the following questions: (i) Are the quorum signals that induce symbiont bioluminescence also involved in triggering the constriction? (ii) Does improper signaling of constriction affect the normal maintenance of the symbiont population? We manipulated the presence of three factors, the two V. fischeri quorum signal synthases, AinS and LuxI, the transcriptional regulator LuxR, and light emission itself, and found that the major factor triggering and maintaining bottleneck constriction is an as yet unknown effector(s) regulated by LuxIR. Treating the animal with chemical inhibitors of actin polymerization reopened the bottlenecks, recapitulating the host's response to quorum-sensing defective symbionts, as well as suggesting that actin polymerization is the primary mechanism underlying constriction. Finally, we found that these host responses to the presence of symbionts changed as a function of tissue maturation. Taken together, this work broadens our concept of how quorum sensing can regulate host development, thereby allowing bacteria to maintain long-term tissue associations. IMPORTANCE Interbacterial signaling within a host-associated population can have profound effects on the behavior of the bacteria, for instance, in their production of virulence/colonization factors; in addition, such signaling can dictate the nature of the outcome for the host, in both pathogenic and beneficial associations. Using the monospecific squid-vibrio model of symbiosis, we examined how quorum-sensing regulation by the Vibrio fischeri population induces a biogeographic tissue phenotype that promotes the retention of this extracellular symbiont within the light organ of its host, Euprymna scolopes. Understanding the influence of bacterial symbionts on key sites of tissue architecture has implications for all horizontally transmitted symbioses, especially those that colonize an epithelial surface within the host.
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28
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Getting the Message Out: the Many Modes of Host-Symbiont Communication during Early-Stage Establishment of the Squid-Vibrio Partnership. mSystems 2021; 6:e0086721. [PMID: 34581595 PMCID: PMC8547416 DOI: 10.1128/msystems.00867-21] [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] [Indexed: 01/12/2023] Open
Abstract
Symbiosis, by its basic nature, depends on partner interactions that are mediated by cues and signals. This kind of critical reciprocal communication shapes the trajectory of host-microbe associations from their onset through their maturation and is typically mediated by both biochemical and biomechanical influences. Symbiotic partnerships often involve communities composed of dozens to hundreds of microbial species, for which resolving the precise nature of these partner interactions is highly challenging. Naturally occurring binary associations, such as those between certain legumes, nematodes, fishes, and squids, and their specific bacterial partner species offer the opportunity to examine interactions with high resolution and at the scale at which the interactions occur. The goals of this review are to provide the conceptual framework for evolutionarily conserved drivers of host-symbiont communication in animal associations and to offer a window into some mechanisms of this phenomenon as discovered through the study of the squid-vibrio model. The discussion focuses upon the early events that lead to persistence of the symbiotic partnership. The biophysical and biochemical determinants of the initial hours of dialogue between partners and how the symbiosis is shaped by the environment that is created by their reciprocal interactions are key topics that have been difficult to approach in more complex systems. Through our research on the squid-vibrio system, we provide insight into the intricate temporal and spatial complexity that underlies the molecular and cellular events mediating successful microbial colonization of the host animal.
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29
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Dual oxidase enables insect gut symbiosis by mediating respiratory network formation. Proc Natl Acad Sci U S A 2021; 118:2020922118. [PMID: 33649233 DOI: 10.1073/pnas.2020922118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Most animals harbor a gut microbiota that consists of potentially pathogenic, commensal, and mutualistic microorganisms. Dual oxidase (Duox) is a well described enzyme involved in gut mucosal immunity by the production of reactive oxygen species (ROS) that antagonizes pathogenic bacteria and maintains gut homeostasis in insects. However, despite its nonspecific harmful activity on microorganisms, little is known about the role of Duox in the maintenance of mutualistic gut symbionts. Here we show that, in the bean bug Riptortus pedestris, Duox-dependent ROS did not directly contribute to epithelial immunity in the midgut in response to its mutualistic gut symbiont, Burkholderia insecticola Instead, we found that the expression of Duox is tracheae-specific and its down-regulation by RNAi results in the loss of dityrosine cross-links in the tracheal protein matrix and a collapse of the respiratory system. We further demonstrated that the establishment of symbiosis is a strong oxygen sink triggering the formation of an extensive network of tracheae enveloping the midgut symbiotic organ as well as other organs, and that tracheal breakdown by Duox RNAi provokes a disruption of the gut symbiosis. Down-regulation of the hypoxia-responsive transcription factor Sima or the regulators of tracheae formation Trachealess and Branchless produces similar phenotypes. Thus, in addition to known roles in immunity and in the formation of dityrosine networks in diverse extracellular matrices, Duox is also a crucial enzyme for tracheal integrity, which is crucial to sustain mutualistic symbionts and gut homeostasis. We expect that this is a conserved function in insects.
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30
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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: 41] [Impact Index Per Article: 13.7] [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.
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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.
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31
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Elston KM, Leonard SP, Geng P, Bialik SB, Robinson E, Barrick JE. Engineering insects from the endosymbiont out. Trends Microbiol 2021; 30:79-96. [PMID: 34103228 DOI: 10.1016/j.tim.2021.05.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/19/2021] [Accepted: 05/11/2021] [Indexed: 01/28/2023]
Abstract
Insects are an incredibly diverse group of animals with species that benefit and harm natural ecosystems, agriculture, and human health. Many insects have consequential associations with microbes: bacterial symbionts may be embedded in different insect tissues and cell types, inherited across insect generations, and required for insect survival and reproduction. Genetically engineering insect symbionts is key to understanding and harnessing these associations. We summarize different types of insect-bacteria relationships and review methods used to genetically modify endosymbiont and gut symbiont species. Finally, we discuss recent studies that use this approach to study symbioses, manipulate insect-microbe interactions, and influence insect biology. Further progress in insect symbiont engineering promises to solve societal challenges, ranging from controlling pests to protecting pollinator health.
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Affiliation(s)
- Katherine M Elston
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Sean P Leonard
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Peng Geng
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Sarah B Bialik
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Elizabeth Robinson
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Jeffrey E Barrick
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA.
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32
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The Gut Microbiota of the Insect Infraorder Pentatomomorpha (Hemiptera: Heteroptera) for the Light of Ecology and Evolution. Microorganisms 2021; 9:microorganisms9020464. [PMID: 33672230 PMCID: PMC7926433 DOI: 10.3390/microorganisms9020464] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 02/18/2021] [Accepted: 02/19/2021] [Indexed: 01/05/2023] Open
Abstract
The stinkbugs of the infraorder Pentatomomorpha are a group of important plant sap-feeding insects, which host diverse microorganisms. Some are located in their complex morphological midgut compartments, while some within the specialized bacteriomes of insect hosts. This perpetuation of symbioses through host generations is reinforced via the diverse routes of vertical transmission or environmental acquisition of the symbionts. These symbiotic partners, reside either through the extracellular associations in midgut or intracellular associations in specialized cells, not only have contributed nutritional benefits to the insect hosts but also shaped their ecological and evolutionary basis. The stinkbugs and gut microbe symbioses present a valuable model that provides insights into symbiotic interactions between agricultural insects and microorganisms and may become potential agents for insect pest management.
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33
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Schmidt K, Engel P. Mechanisms underlying gut microbiota-host interactions in insects. J Exp Biol 2021; 224:224/2/jeb207696. [PMID: 33509844 DOI: 10.1242/jeb.207696] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Insects are the most diverse group of animals and colonize almost all environments on our planet. This diversity is reflected in the structure and function of the microbial communities inhabiting the insect digestive system. As in mammals, the gut microbiota of insects can have important symbiotic functions, complementing host nutrition, facilitating dietary breakdown or providing protection against pathogens. There is an increasing number of insect models that are experimentally tractable, facilitating mechanistic studies of gut microbiota-host interactions. In this Review, we will summarize recent findings that have advanced our understanding of the molecular mechanisms underlying the symbiosis between insects and their gut microbiota. We will open the article with a general introduction to the insect gut microbiota and then turn towards the discussion of particular mechanisms and molecular processes governing the colonization of the insect gut environment as well as the diverse beneficial roles mediated by the gut microbiota. The Review highlights that, although the gut microbiota of insects is an active field of research with implications for fundamental and applied science, we are still in an early stage of understanding molecular mechanisms. However, the expanding capability to culture microbiomes and to manipulate microbe-host interactions in insects promises new molecular insights from diverse symbioses.
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Affiliation(s)
- Konstantin Schmidt
- Department of Fundamental Microbiology, University of Lausanne, 1015, Lausanne, Switzerland
| | - Philipp Engel
- Department of Fundamental Microbiology, University of Lausanne, 1015, Lausanne, Switzerland
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34
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Gilbert SF. Evolutionary developmental biology and sustainability: A biology of resilience. Evol Dev 2021; 23:273-291. [PMID: 33400344 DOI: 10.1111/ede.12366] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 12/14/2020] [Accepted: 12/16/2020] [Indexed: 12/26/2022]
Abstract
Evolutionary developmental biology, and especially ecological developmental biology, is essential for discussions of sustainability and the responses to global climate change. First, this paper explores examples of animals that have successfully altered their development to accommodate human-made changes to their environments. We next document the ability of global warming to disrupt the development of those organisms with temperature-dependent sex-determination or with phenologies coordinating that organism's development with those of other species. The thermotolerance of Homo sapiens is also related to key developmental factors concerning brain development and maintenance, and the development of corals, the keystone organisms of tropical reefs, is discussed in relation to global warming as well as to other anthropogenic changes. While teratogenic and endocrine-disrupting compounds are not discussed in this essay, the ability of glyphosate herbicides to block insect development is highlighted. Last, the paper discusses the need to creatively integrate developmental biology with ecological, political, religious, and economic perspectives, as the flourishing of contemporary species may require altering the ways that Western science has considered the categories of nature, culture, and self.
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Affiliation(s)
- Scott F Gilbert
- Department of Biology, Swarthmore College, Swarthmore, Pennsylvania, USA
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35
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Contributions of protein microenvironment in tannase industrial applicability: An in-silico comparative study of pathogenic and non-pathogenic bacterial tannase. Heliyon 2020; 6:e05359. [PMID: 33241136 PMCID: PMC7672291 DOI: 10.1016/j.heliyon.2020.e05359] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 06/22/2020] [Accepted: 10/23/2020] [Indexed: 01/09/2023] Open
Abstract
Tannase is an inducible industrially important enzyme, produced by several microorganisms. A large number of bacteria have reported as tannase producers; however, some of them are pathogenic in nature. Therefore, it is quite uncertain whether the application of these tannase enzymes from such pathogenic bacteria is suitable for industries and human welfare. Till date, there is no clear evidence regarding which group of bacteria (non-pathogenic or pathogenic) is better suited for their application in the edge of industries with particular reference to the food industry. The present study is following the findings of the above queries. In this study, a large number of tannase protein sequences have been retrieved from the databases, including both non-pathogenic and pathogenic bacterial species. Physiochemical and evolutionary properties of those sequences have been evaluated. Results have shown that non-pathogenic bacterial tannase possesses a high number of acidic and basic amino acid residues as compared to their pathogenic counterparts. The acidic and basic amino acid residues of tannase provide unique microenvironment to it. In the other hand, the numbers of disorder forming residues are higher in tannase sequences of pathogenic bacteria. The study of tannase microenvironment leads in the formation of salt bridges, which finally favoring the stability and proper functioning of tannase. This is the first report of such observation on tannase enzyme using in silico approach. Study of the microenvironment concept will be helpful in protein engineering.
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36
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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: 24] [Impact Index Per Article: 6.0] [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.
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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
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Ravenscraft A, Thairu MW, Hansen AK, Hunter MS. Continent-Scale Sampling Reveals Fine-Scale Turnover in a Beneficial Bug Symbiont. Front Microbiol 2020; 11:1276. [PMID: 32636818 PMCID: PMC7316890 DOI: 10.3389/fmicb.2020.01276] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 05/19/2020] [Indexed: 12/05/2022] Open
Abstract
Many members of animal-associated microbial communities, including the gut flora, are acquired from their host’s environment. While many of these communities are species rich, some true bugs (Hemiptera) in the superfamilies Lygaeoidea and Coreidae allow only ingested Burkholderia to colonize and reproduce in a large portion of the midgut. We studied the spatial structuring of Burkholderia associated with a widespread omnivorous bug genus, Jalysus (Berytidae). We sampled Wickham’s stilt bug, Jalysus wickhami, across the United States and performed limited sampling of its sister species, the spined stilt bug Jalysus spinosus. We asked: (1) What Burkholderia strains are hosted by Jalysus at different locations? (2) Does host insect species, host plant species, or location influence the strain these insects acquire? (3) How does Burkholderia affect the development and reproductive fitness of J. wickhami? We found: (1) Sixty-one Burkholderia strains were present across a sample of 352 individuals, but one strain dominated, accounting for almost half of all symbiont reads. Most strains were closely related to other hemipteran Burkholderia symbionts. (2) Many individuals hosted more than one strain of Burkholderia. (3) J. wickhami and J. spinosus did not differ in the strains they hosted. (4) Insects that fed on different plant species tended to host different Burkholderia, but this accounted for only 4% of the variation in strains hosted. In contrast, the location at which an insect was collected explained 27% of the variation in symbiont strains. (5) Burkholderia confers important fitness benefits to J. wickhami. In laboratory experiments, aposymbiotic (Burkholderia-free) insects developed more slowly and laid fewer eggs than symbiotic (Burkholderia-colonized) insects. (6) In the lab, nymphs sometimes acquired Burkholderia via indirect exposure to adults, indicating that horizontal symbiont transmission can occur via adult insect-mediated enrichment of Burkholderia in the local environment – a phenomenon not previously reported in bug-Burkholderia relationships. Taken together, the results suggest that for these bugs, critical nutritional requirements are outsourced to a highly diverse and spatially structured collection of Burkholderia strains acquired from the environment and, occasionally, from conspecific adults.
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Affiliation(s)
- Alison Ravenscraft
- Center for Insect Science, University of Arizona, Tucson, AZ, United States
| | - Margaret W Thairu
- Department of Entomology, University of California, Riverside, Riverside, CA, United States
| | - Allison K Hansen
- Department of Entomology, University of California, Riverside, Riverside, CA, United States
| | - Martha S Hunter
- Department of Entomology, University of Arizona, Tucson, AZ, United States
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Genomic Comparison of Insect Gut Symbionts from Divergent Burkholderia Subclades. Genes (Basel) 2020; 11:genes11070744. [PMID: 32635398 PMCID: PMC7397029 DOI: 10.3390/genes11070744] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 06/29/2020] [Accepted: 07/01/2020] [Indexed: 01/01/2023] Open
Abstract
Stink bugs of the superfamilies Coreoidea and Lygaeoidea establish gut symbioses with environmentally acquired bacteria of the genus Burkholderia sensu lato. In the genus Burkholderia, the stink bug-associated strains form a monophyletic clade, named stink bug-associated beneficial and environmental (SBE) clade (or Caballeronia). Recently, we revealed that members of the family Largidae of the superfamily Pyrrhocoroidea are associated with Burkholderia but not specifically with the SBE Burkholderia; largid bugs harbor symbionts that belong to a clade of plant-associated group of Burkholderia, called plant-associated beneficial and environmental (PBE) clade (or Paraburkholderia). To understand the genomic features of Burkholderia symbionts of stink bugs, we isolated two symbiotic Burkholderia strains from a bordered plant bug Physopellta gutta (Pyrrhocoroidea: Largidae) and determined their complete genomes. The genome sizes of the insect-associated PBE (iPBE) are 9.5 Mb and 11.2 Mb, both of which are larger than the genomes of the SBE Burkholderia symbionts. A whole-genome comparison between two iPBE symbionts and three SBE symbionts highlighted that all previously reported symbiosis factors are shared and that 282 genes are specifically conserved in the five stink bug symbionts, over one-third of which have unknown function. Among the symbiont-specific genes, about 40 genes formed a cluster in all five symbionts; this suggests a "symbiotic island" in the genome of stink bug-associated Burkholderia.
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