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Silva FJ, Domínguez-Santos R, Latorre A, García-Ferris C. Comparative Transcriptomics of Fat Bodies between Symbiotic and Quasi-Aposymbiotic Adult Females of Blattella germanica with Emphasis on the Metabolic Integration with Its Endosymbiont Blattabacterium and Its Immune System. Int J Mol Sci 2024; 25:4228. [PMID: 38673813 PMCID: PMC11050582 DOI: 10.3390/ijms25084228] [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: 02/21/2024] [Revised: 04/02/2024] [Accepted: 04/04/2024] [Indexed: 04/28/2024] Open
Abstract
We explored the metabolic integration of Blattella germanica and its obligate endosymbiont Blattabacterium cuenoti by the transcriptomic analysis of the fat body of quasi-aposymbiotic cockroaches, where the endosymbionts were almost entirely removed with rifampicin. Fat bodies from quasi-aposymbiotic insects displayed large differences in gene expression compared to controls. In quasi-aposymbionts, the metabolism of phenylalanine and tyrosine involved in cuticle sclerotization and pigmentation increased drastically to compensate for the deficiency in the biosynthesis of these amino acids by the endosymbionts. On the other hand, the uricolytic pathway and the biosynthesis of uric acid were severely decreased, probably because the reduced population of endosymbionts was unable to metabolize urea to ammonia. Metabolite transporters that could be involved in the endosymbiosis process were identified. Immune system and antimicrobial peptide (AMP) gene expression was also reduced in quasi-aposymbionts, genes encoding peptidoglycan-recognition proteins, which may provide clues for the maintenance of the symbiotic relationship, as well as three AMP genes whose involvement in the symbiotic relationship will require additional analysis. Finally, a search for AMP-like factors that could be involved in controlling the endosymbiont identified two orphan genes encoding proteins smaller than 200 amino acids underexpressed in quasi-aposymbionts, suggesting a role in the host-endosymbiont relationship.
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Affiliation(s)
- Francisco J. Silva
- Institute for Integrative Systems Biology (I2SysBio), University of Valencia and Spanish Research Council, 46980 Paterna, Spain; (R.D.-S.); (A.L.)
- Genomics and Health Area, Foundation for the Promotion of Sanitary and Biomedical Research of the Valencia Region, 46020 Valencia, Spain
| | - Rebeca Domínguez-Santos
- Institute for Integrative Systems Biology (I2SysBio), University of Valencia and Spanish Research Council, 46980 Paterna, Spain; (R.D.-S.); (A.L.)
- Genomics and Health Area, Foundation for the Promotion of Sanitary and Biomedical Research of the Valencia Region, 46020 Valencia, Spain
| | - Amparo Latorre
- Institute for Integrative Systems Biology (I2SysBio), University of Valencia and Spanish Research Council, 46980 Paterna, Spain; (R.D.-S.); (A.L.)
- Genomics and Health Area, Foundation for the Promotion of Sanitary and Biomedical Research of the Valencia Region, 46020 Valencia, Spain
| | - Carlos García-Ferris
- Institute for Integrative Systems Biology (I2SysBio), University of Valencia and Spanish Research Council, 46980 Paterna, Spain; (R.D.-S.); (A.L.)
- Genomics and Health Area, Foundation for the Promotion of Sanitary and Biomedical Research of the Valencia Region, 46020 Valencia, Spain
- Department of Biochemistry and Molecular Biology, University of Valencia, 46100 Burjassot, Spain
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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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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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Huynh K, Kibrom A, Donald BR, Zhou P. Discovery, characterization, and redesign of potent antimicrobial thanatin orthologs from Chinavia ubica and Murgantia histrionica targeting E. coli LptA. J Struct Biol X 2023; 8:100091. [PMID: 37416832 PMCID: PMC10320583 DOI: 10.1016/j.yjsbx.2023.100091] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 06/07/2023] [Accepted: 06/08/2023] [Indexed: 07/08/2023] Open
Abstract
Podisus maculiventris thanatin has been reported as a potent antimicrobial peptide with antibacterial and antifungal activity. Its antibiotic activity has been most thoroughly characterized against E. coli and shown to interfere with multiple pathways, such as the lipopolysaccharide transport (LPT) pathway comprised of seven different Lpt proteins. Thanatin binds to E. coli LptA and LptD, thus disrupting the LPT complex formation and inhibiting cell wall synthesis and microbial growth. Here, we performed a genomic database search to uncover novel thanatin orthologs, characterized their binding to E. coli LptA using bio-layer interferometry, and assessed their antimicrobial activity against E. coli. We found that thanatins from Chinavia ubica and Murgantia histrionica bound tighter (by 3.6- and 2.2-fold respectively) to LptA and exhibited more potent antibiotic activity (by 2.1- and 2.8-fold respectively) than the canonical thanatin from P. maculiventris. We crystallized and determined the LptA-bound complex structures of thanatins from C. ubica (1.90 Å resolution), M. histrionica (1.80 Å resolution), and P. maculiventris (2.43 Å resolution) to better understand their mechanism of action. Our structural analysis revealed that residues A10 and I21 in C. ubica and M. histrionica thanatin are important for improving the binding interface with LptA, thus overall improving the potency of thanatin against E. coli. We also designed a stapled variant of thanatin that removes the need for a disulfide bond but retains the ability to bind LptA and antibiotic activity. Our discovery presents a library of novel thanatin sequences to serve as starting scaffolds for designing more potent antimicrobial therapeutics.
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Affiliation(s)
- Kelly Huynh
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, United States
| | - Amanuel Kibrom
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, United States
| | - Bruce R. Donald
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, United States
- Department of Computer Science, Duke University, Durham, NC, United States
| | - Pei Zhou
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, United States
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5
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Gook DH, Jung M, Kim S, Lee DH. Species diversity of environmentally-transmitted bacteria colonizing Riptortus pedestris (Hemiptera: Alydidae) and symbiotic effects of the most dominant bacteria. Sci Rep 2023; 13:15166. [PMID: 37704685 PMCID: PMC10499786 DOI: 10.1038/s41598-023-42419-0] [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: 03/31/2023] [Accepted: 09/10/2023] [Indexed: 09/15/2023] Open
Abstract
Riptortus pedestris (Hemiptera: Alydidae) establish endosymbiosis with specific bacteria from extremely diverse microbiota in soil. To better understand ecology and evolution of the symbiosis, it is important to characterize bacterial species diversity colonizing R. pedestris and evaluate their symbiotic effects. Nonetheless, previous research was limited to a few bacteria strains such as Caballeronia insecticola. In this study, second-instar nymphs were provided with field soils and reared to adult. Then, bacteria colonizing the midgut M4 region of R. pedestris were analyzed for bacterial species identification based on the 16S rRNA gene. First, a total of 15 bacterial species were detected belonging to Burkholderiaceae. Most of R. pedestris were found to harbor single bacterial species, whereas several insects harbored at most two bacterial species simultaneously. Among the total insects harboring single bacterial species, 91.2% harbored genus Caballeronia. The most dominant species was C. jiangsuensis, not previously documented for symbiotic associations with R. pedestris. Second, in laboratory conditions, C. jiangsuensis significantly enhanced the development, body size, and reproductive potentials of R. pedestris, compared to individuals with no symbiotic bacteria. These results add novel information to better understand symbiotic bacteria community establishing in R. pedestris and symbiotic effects on the host insects.
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Affiliation(s)
- Do-Hun Gook
- Department of Life Sciences, Gachon University, Seongnam-daero 1342, Seongnam-si, Gyeonggi-do, South Korea
| | - Minhyung Jung
- Department of Life Sciences, Gachon University, Seongnam-daero 1342, Seongnam-si, Gyeonggi-do, South Korea
| | - Soowan Kim
- Department of Life Sciences, Gachon University, Seongnam-daero 1342, Seongnam-si, Gyeonggi-do, South Korea
| | - Doo-Hyung Lee
- Department of Life Sciences, Gachon University, Seongnam-daero 1342, Seongnam-si, Gyeonggi-do, South Korea.
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6
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Unraveling the Role of Antimicrobial Peptides in Insects. Int J Mol Sci 2023; 24:ijms24065753. [PMID: 36982826 PMCID: PMC10059942 DOI: 10.3390/ijms24065753] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 03/19/2023] Open
Abstract
Antimicrobial peptides (AMPs) are short, mainly positively charged, amphipathic molecules. AMPs are important effectors of the immune response in insects with a broad spectrum of antibacterial, antifungal, and antiparasitic activity. In addition to these well-known roles, AMPs exhibit many other, often unobvious, functions in the host. They support insects in the elimination of viral infections. AMPs participate in the regulation of brain-controlled processes, e.g., sleep and non-associative learning. By influencing neuronal health, communication, and activity, they can affect the functioning of the insect nervous system. Expansion of the AMP repertoire and loss of their specificity is connected with the aging process and lifespan of insects. Moreover, AMPs take part in maintaining gut homeostasis, regulating the number of endosymbionts as well as reducing the number of foreign microbiota. In turn, the presence of AMPs in insect venom prevents the spread of infection in social insects, where the prey may be a source of pathogens.
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Nishide Y, Nagamine K, Kageyama D, Moriyama M, Futahashi R, Fukatsu T. A new antimicrobial peptide, Pentatomicin, from the stinkbug Plautia stali. Sci Rep 2022; 12:16503. [PMID: 36192417 PMCID: PMC9529961 DOI: 10.1038/s41598-022-20427-w] [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: 04/01/2022] [Accepted: 09/13/2022] [Indexed: 12/29/2022] Open
Abstract
Antimicrobial peptides (AMPs) play crucial roles in the innate immunity of diverse organisms, which exhibit remarkable diversity in size, structural property and antimicrobial spectrum. Here, we describe a new AMP, named Pentatomicin, from the stinkbug Plautia stali (Hemiptera: Pentatomidae). Orthologous nucleotide sequences of Pentatomicin were present in stinkbugs and beetles but not in other insect groups. Notably, orthologous sequences were also detected from a horseshoe crab, cyanobacteria and proteobacteria, suggesting the possibility of inter-domain horizontal gene transfers of Pentatomicin and allied protein genes. The recombinant protein of Pentatomicin was effective against an array of Gram-positive bacteria but not against Gram-negative bacteria. Upon septic shock, the expression of Pentatomicin drastically increased in a manner similar to other AMPs. On the other hand, unlike other AMPs, mock and saline injections increased the expression of Pentatomicin. RNAi-mediated downregulation of Imd pathway genes (Imd and Relish) and Toll pathway genes (MyD88 and Dorsal) revealed that the expression of Pentatomicin is under the control of Toll pathway. Being consistent with in vitro effectiveness of the recombinant protein, adult insects injected with dsRNA of Pentatomicin exhibited higher vulnerability to Gram-positive Staphylococcus aureus than to Gram-negative Escherichia coli. We discovered high levels of Pentatomicin expression in eggs, which is atypical of other AMPs and suggestive of its biological functioning in eggs. Contrary to the expectation, however, RNAi-mediated downregulation of Pentatomicin did not affect normal embryonic development of P. stali. Moreover, the downregulation of Pentatomicin in eggs did not affect vertical symbiont transmission to the offspring even under heavily contaminated conditions, which refuted our expectation that the antimicrobial activity of Pentatomicin may contribute to egg surface-mediated symbiont transmission by suppressing microbial contaminants.
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Affiliation(s)
- Yudai Nishide
- Institute of Agrobiological Sciences Ohwashi, National Agriculture and Food Research Organization (NARO), Tsukuba, 305-8634, Japan.
| | - Keisuke Nagamine
- Institute of Agrobiological Sciences Ohwashi, National Agriculture and Food Research Organization (NARO), Tsukuba, 305-8634, Japan
- Japan Society for the Promotion of Science (JSPS), Tokyo, 102-0083, Japan
| | - Daisuke Kageyama
- Institute of Agrobiological Sciences Ohwashi, National Agriculture and Food Research Organization (NARO), Tsukuba, 305-8634, Japan
| | - Minoru Moriyama
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan
| | - Ryo Futahashi
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan.
| | - Takema Fukatsu
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan.
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, 113-0033, Japan.
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, 305-8572, Japan.
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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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Armitage SA, Genersch E, McMahon DP, Rafaluk-Mohr C, Rolff J. Tripartite interactions: how immunity, microbiota and pathogens interact and affect pathogen virulence evolution. CURRENT OPINION IN INSECT SCIENCE 2022; 50:100871. [PMID: 34999035 DOI: 10.1016/j.cois.2021.12.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 12/22/2021] [Accepted: 12/29/2021] [Indexed: 06/14/2023]
Abstract
The bipartite interactions between insect hosts and their bacterial gut microbiota, or their bacterial pathogens, are empirically and theoretically well-explored. However, direct, and indirect tripartite interactions will also likely occur inside a host. These interactions will almost certainly affect the trajectory of pathogen virulence evolution, an area that is currently under researched. The interactions within tripartite associations can be competitive, that is, exploitative-competition, interference-competition or apparent-competition. Competitive interactions will be significantly influenced by non-competitive effects, for example, immunopathology, immunosuppression, and microbiota-mediated tolerance. Considering a combination of these interactions and effects, will enable an increased understanding of the evolution of pathogen virulence. This new perspective allows us to identify several novel research questions, which we hope will be a useful framework for future research.
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Affiliation(s)
- Sophie Ao Armitage
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straße 1-3, 14195 Berlin, Germany.
| | - Elke Genersch
- Institute for Bee Research, Friedrich-Engels-Straße 32, 16540 Hohen Neuendorf, Germany; Institute of Microbiology and Epizootics, Faculty of Veterinary Medicine, Freie Universität Berlin, Robert-von-Ostertag-Straße 7-13, 14163 Berlin, Germany
| | - Dino P McMahon
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straße 1-3, 14195 Berlin, Germany; Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205 Berlin, Germany
| | - Charlotte Rafaluk-Mohr
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straße 1-3, 14195 Berlin, Germany
| | - Jens Rolff
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straße 1-3, 14195 Berlin, Germany; Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, Germany
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10
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Lee J, Cha WH, Lee DW. Multiple Precursor Proteins of Thanatin Isoforms, an Antimicrobial Peptide Associated With the Gut Symbiont of Riptortus pedestris. Front Microbiol 2022; 12:796548. [PMID: 35069496 PMCID: PMC8767025 DOI: 10.3389/fmicb.2021.796548] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 12/10/2021] [Indexed: 01/08/2023] Open
Abstract
Thanatin is an antimicrobial peptide (AMP) generated by insects for defense against bacterial infections. In the present study, we performed cDNA cloning of thanatin and found the presence of multiple precursor proteins from the bean bug, Riptortus pedestris. The cDNA sequences encoded 38 precursor proteins, generating 13 thanatin isoforms. In the phylogenetic analysis, thanatin isoforms were categorized into two groups based on the presence of the membrane attack complex/perforin (MACPF) domain. In insect-bacterial symbiosis, specific substances are produced by the immune system of the host insect and are known to modulate the symbiont’s population. Therefore, to determine the biological function of thanatin isoforms in symbiosis, the expression levels of three AMP genes were compared between aposymbiotic insects and symbiotic R. pedestris. The expression levels of the thanatin genes were significantly increased in the M4 crypt, a symbiotic organ, of symbiotic insects upon systemic bacterial injection. Further, synthetic thanatin isoforms exhibited antibacterial activity against gut-colonized Burkholderia symbionts rather than in vitro-cultured Burkholderia cells. Interestingly, the suppression of thanatin genes significantly increased the population of Burkholderia gut symbionts in the M4 crypt under systemic Escherichia coli K12 injection. Overgrown Burkholderia gut symbionts were observed in the hemolymph of host insects and exhibited insecticidal activity. Taken together, these results suggest that thanatin of R. pedestris is a host-derived symbiotic factor and an AMP that controls the population of gut-colonized Burkholderia symbionts.
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Affiliation(s)
- Junbeom Lee
- Metabolomics Research Center for Functional Materials, Kyungsung University, Busan, South Korea
| | - Wook Hyun Cha
- Department of Bio-Safety, Kyungsung University, Busan, South Korea
| | - Dae-Weon Lee
- Metabolomics Research Center for Functional Materials, Kyungsung University, Busan, South Korea.,Department of Bio-Safety, Kyungsung University, Busan, South Korea
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11
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Zhao X, Xu Y, Viel JH, Kuipers OP. Semisynthetic Macrocyclic Lipo-lanthipeptides Display Antimicrobial Activity Against Bacterial Pathogens. ACS Synth Biol 2021; 10:1980-1991. [PMID: 34347446 PMCID: PMC8383303 DOI: 10.1021/acssynbio.1c00161] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A large number of antimicrobial peptides depend on intramolecular disulfide bonds for their biological activity. However, the relative instability of disulfide bonds has limited the potential of some of these peptides to be developed into therapeutics. Conversely, peptides containing intramolecular (methyl)lanthionine-based bonds, lanthipeptides, are highly stable under a broader range of biological and physical conditions. Here, the class-II lanthipeptide synthetase CinM, from the cinnamycin gene cluster, was employed to create methyllanthionine stabilized analogues of disulfide-bond-containing antimicrobial peptides. The resulting analogues were subsequently modified in vitro by adding lipid tails of variable lengths through chemical addition. Finally, the created compounds were characterized by MIC tests against several relevant pathogens, killing assays, membrane permeability assays, and hemolysis assays. It was found that CinM could successfully install methyllanthionine bonds at the intended positions of the analogues and that the lipidated macrocyclic core peptides have bactericidal activity against tested Gram-positive and Gram-negative pathogenic bacteria. Additionally, fluorescence microscopy assays revealed that the lipidated compounds disrupt the bacterial membrane and lyse bacterial cells, hinting toward a potential mode of action. Notably, the semisynthesized macrocyclic lipo-lanthipeptides show low hemolytic activity. These results show that the methods developed here extend the toolbox for novel antimicrobial development and might enable the further development of novel compounds with killing activity against relevant pathogenic bacteria.
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Affiliation(s)
- Xinghong Zhao
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen 9747 AG, The Netherlands
| | - Yanli Xu
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen 9747 AG, The Netherlands
| | - Jakob H. Viel
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen 9747 AG, The Netherlands
| | - Oscar P. Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen 9747 AG, The Netherlands
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12
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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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13
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Zhao X, Kuipers OP. Nisin- and Ripcin-Derived Hybrid Lanthipeptides Display Selective Antimicrobial Activity against Staphylococcus aureus. ACS Synth Biol 2021; 10:1703-1714. [PMID: 34156232 PMCID: PMC8291769 DOI: 10.1021/acssynbio.1c00080] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Indexed: 12/14/2022]
Abstract
Lanthipeptides are (methyl)lanthionine ring-containing ribosomally synthesized and post-translationally modified peptides (RiPPs). Many lanthipeptides show strong antimicrobial activity against bacterial pathogens, including antibiotic-resistant bacterial pathogens. The group of disulfide-bond-containing antimicrobial peptides (AMPs) is well-known in nature and forms a rich source of templates for the production of novel peptides with corresponding (methyl)lanthionine analogues instead of disulfides. Here, we show that novel macrocyclic lanthipeptides (termed thanacin and ripcin) can be synthesized using the known antimicrobials thanatin and rip-thanatin as templates. Notably, the synthesized nisin(1-20)-ripcin hybrid lanthipeptides (ripcin B-G) showed selective antimicrobial activity against S. aureus, including an antibiotic-resistant MRSA strain. Interestingly, ripcin B-G, which are hybrid peptides of nisin(1-20) and ripcin that are each inactive against Gram-negative pathogens, showed substantial antimicrobial activity against the tested Gram-negative pathogens. Moreover, ripcin B-G was highly resistant against the nisin resistance protein (NSR; a peptidase that removes the C-terminal 6 amino acids of nisin and strongly reduces its antimicrobial activity), opposed to nisin itself. This study provides an example of converting disulfide-bond-based AMPs into (methyl)lanthionine-based macrocyclic hybrid lanthipeptides and can yield antimicrobial peptides with selective antimicrobial activity against S. aureus.
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Affiliation(s)
- Xinghong Zhao
- Department
of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology
Institute, University of Groningen, Groningen, 9747 AG, The Netherlands
| | - Oscar P. Kuipers
- Department
of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology
Institute, University of Groningen, Groningen, 9747 AG, The Netherlands
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14
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Chung SH, Feng H, Jander G. Engineering pest tolerance through plant-mediated RNA interference. CURRENT OPINION IN PLANT BIOLOGY 2021; 60:102029. [PMID: 33639339 DOI: 10.1016/j.pbi.2021.102029] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 02/04/2021] [Accepted: 02/07/2021] [Indexed: 05/18/2023]
Abstract
Expression of insect-targeted RNA interference (RNAi) constructs in transgenic plants is a promising approach for agricultural pest control. Compared to conventional chemical insecticides, RNAi target specificity is high and the potential for negative environmental effects is low. However, although numerous laboratory studies show insect growth inhibition by double stranded RNA or artificial microRNA, few of these constructs have been moved into commercial application as genetically engineered plants. Variation in RNA degradation, uptake, processing, and systemic transport in insects can influence interspecific and intraspecific differences in RNAi efficacy and the development of resistance to RNAi in agricultural settings. Further research is needed, both to identify optimal gene targets for efficient RNAi in pest species and to reduce the potential for off-target effects in beneficial species.
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Affiliation(s)
- Seung Ho Chung
- Boyce Thompson Institute, 533 Tower Road, Ithaca, NY 14853, USA
| | - Honglin Feng
- Boyce Thompson Institute, 533 Tower Road, Ithaca, NY 14853, USA
| | - Georg Jander
- Boyce Thompson Institute, 533 Tower Road, Ithaca, NY 14853, USA.
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15
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Muhammad A, Habineza P, Wang X, Xiao R, Ji T, Hou Y, Shi Z. Spätzle Homolog-Mediated Toll-Like Pathway Regulates Innate Immune Responses to Maintain the Homeostasis of Gut Microbiota in the Red Palm Weevil, Rhynchophorus ferrugineus Olivier (Coleoptera: Dryophthoridae). Front Microbiol 2020; 11:846. [PMID: 32523559 PMCID: PMC7261851 DOI: 10.3389/fmicb.2020.00846] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 04/08/2020] [Indexed: 11/13/2022] Open
Abstract
Spätzle (Spz) is a dimeric ligand that responds to the Gram-positive bacterial or fungal infection by binding Toll receptors to induce the secretion of antimicrobial peptides. However, whether the Toll-like signaling pathway mediates the innate immunity of Rhynchophorus ferrugineus to modulate the homeostasis of gut microbiota has not been determined. In this study, we found that a Spz homolog, RfSpätzle, is a secretory protein comprising a signal peptide and a conservative Spz domain. RT-qPCR analysis revealed that RfSpätzle was significantly induced to be expressed in the fat body and gut by the systemic and oral infection with pathogenic microbes. The expression levels of two antimicrobial peptide genes, RfColeoptericin and RfCecropin, were downregulated significantly by RfSpätzle knockdown, indicating that their secretion is under the regulation of the RfSpätzle-mediated signaling pathway. After being challenged by pathogenic microbes, the cumulative mortality rate of RfSpätzle-silenced individuals was drastically increased as compared to that of the controls. Further analysis indicated that these larvae possessed the diminished antibacterial activity. Moreover, RfSpätzle knockdown altered the relative abundance of gut bacteria at the phylum and family levels. Taken together, these findings suggest that RfSpätzle is involved in RPW immunity to confer protection and maintain the homeostasis of gut microbiota by mediating the production of antimicrobial peptides.
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Affiliation(s)
- Abrar Muhammad
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian Provincial Key Laboratory of Insect Ecology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Prosper Habineza
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian Provincial Key Laboratory of Insect Ecology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xinghong Wang
- Guizhou Institute of Biology, Guizhou Academy of Sciences, Guiyang, China
| | - Rong Xiao
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian Provincial Key Laboratory of Insect Ecology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Tianliang Ji
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian Provincial Key Laboratory of Insect Ecology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Youming Hou
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian Provincial Key Laboratory of Insect Ecology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zhanghong Shi
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian Provincial Key Laboratory of Insect Ecology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
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16
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Burkholderia insecticola triggers midgut closure in the bean bug Riptortus pedestris to prevent secondary bacterial infections of midgut crypts. ISME JOURNAL 2020; 14:1627-1638. [PMID: 32203122 DOI: 10.1038/s41396-020-0633-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 03/03/2020] [Accepted: 03/10/2020] [Indexed: 02/06/2023]
Abstract
In addition to abiotic triggers, biotic factors such as microbial symbionts can alter development of multicellular organisms. Symbiont-mediated morphogenesis is well-investigated in plants and marine invertebrates but rarely in insects despite the enormous diversity of insect-microbe symbioses. The bean bug Riptortus pedestris is associated with Burkholderia insecticola which are acquired from the environmental soil and housed in midgut crypts. To sort symbionts from soil microbiota, the bean bug develops a specific organ called the "constricted region" (CR), a narrow and symbiont-selective channel, located in the midgut immediately upstream of the crypt-bearing region. In this study, inoculation of fluorescent protein-labeled symbionts followed by spatiotemporal microscopic observations revealed that after the initial passage of symbionts through the CR, it closes within 12-18 h, blocking any potential subsequent infection events. The "midgut closure" developmental response was irreversible, even after symbiont removal from the crypts by antibiotics. It never occurred in aposymbiotic insects, nor in insects infected with nonsymbiotic bacteria or B. insecticola mutants unable to cross the CR. However, species of the genus Burkholderia and its outgroup Pandoraea that can pass the CR and partially colonize the midgut crypts induce the morphological alteration, suggesting that the molecular trigger signaling the midgut closure is conserved in this bacterial lineage. We propose that this drastic and quick alteration of the midgut morphology in response to symbiont infection is a mechanism for stabilizing the insect-microbe gut symbiosis and contributes to host-symbiont specificity in a symbiosis without vertical transmission.
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17
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Kaltenpoth M, Flórez LV. Versatile and Dynamic Symbioses Between Insects and Burkholderia Bacteria. ANNUAL REVIEW OF ENTOMOLOGY 2020; 65:145-170. [PMID: 31594411 DOI: 10.1146/annurev-ento-011019-025025] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Symbiotic associations with microorganisms represent major sources of ecological and evolutionary innovations in insects. Multiple insect taxa engage in symbioses with bacteria of the genus Burkholderia, a diverse group that is widespread across different environments and whose members can be mutualistic or pathogenic to plants, fungi, and animals. Burkholderia symbionts provide nutritional benefits and resistance against insecticides to stinkbugs, defend Lagria beetle eggs against pathogenic fungi, and may be involved in nitrogen metabolism in ants. In contrast to many other insect symbioses, the known associations with Burkholderia are characterized by environmental symbiont acquisition or mixed-mode transmission, resulting in interesting ecological and evolutionary dynamics of symbiont strain composition. Insect-Burkholderia symbioses present valuable model systems from which to derive insights into general principles governing symbiotic interactions because they are often experimentally and genetically tractable and span a large fraction of the diversity of functions, localizations, and transmission routes represented in insect symbioses.
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Affiliation(s)
- Martin Kaltenpoth
- Institute of Organismic and Molecular Evolution, Evolutionary Ecology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; ,
| | - Laura V Flórez
- Institute of Organismic and Molecular Evolution, Evolutionary Ecology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany; ,
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18
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Host-symbiont specificity determined by microbe-microbe competition in an insect gut. Proc Natl Acad Sci U S A 2019; 116:22673-22682. [PMID: 31636183 DOI: 10.1073/pnas.1912397116] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Despite the omnipresence of specific host-symbiont associations with acquisition of the microbial symbiont from the environment, little is known about how the specificity of the interaction evolved and is maintained. The bean bug Riptortus pedestris acquires a specific bacterial symbiont of the genus Burkholderia from environmental soil and harbors it in midgut crypts. The genus Burkholderia consists of over 100 species, showing ecologically diverse lifestyles, and including serious human pathogens, plant pathogens, and nodule-forming plant mutualists, as well as insect mutualists. Through infection tests of 34 Burkholderia species and 18 taxonomically diverse bacterial species, we demonstrate here that nonsymbiotic Burkholderia and even its outgroup Pandoraea could stably colonize the gut symbiotic organ and provide beneficial effects to the bean bug when inoculated on aposymbiotic hosts. However, coinoculation revealed that the native symbiont always outcompeted the nonnative bacteria inside the gut symbiotic organ, explaining the predominance of the native Burkholderia symbiont in natural bean bug populations. Hence, the abilities for colonization and cooperation, usually thought of as specific traits of mutualists, are not unique to the native Burkholderia symbiont but, to the contrary, competitiveness inside the gut is a derived trait of the native symbiont lineage only and was thus critical in the evolution of the insect gut symbiont.
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19
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Lee J, Kim CH, Jang HA, Kim JK, Kotaki T, Shinoda T, Shinada T, Yoo JW, Lee BL. Burkholderia gut symbiont modulates titer of specific juvenile hormone in the bean bug Riptortus pedestris. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2019; 99:103399. [PMID: 31195052 DOI: 10.1016/j.dci.2019.103399] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 05/17/2019] [Accepted: 05/17/2019] [Indexed: 06/09/2023]
Abstract
Recent studies have provided molecular evidence that gut symbiotic bacteria modulate host insect development, fitness and reproduction. However, the molecular mechanisms through which gut symbionts regulate these aspects of host physiology remain elusive. To address these questions, we prepared two different Riptortus-Burkholderia insect models, Burkholderia gut symbiont-colonized (Sym) Riptortus pedestris insects and gut symbiont-noncolonized (Apo) insects. Upon LC-MS analyses, juvenile hormone III skipped bisepoxide (JHSB3) was newly identified from Riptortus Apo- and Sym-female and male adults' insect hemolymph and JHSB3 titer in the Apo- and Sym-female insects were measured because JH is important for regulating reproduction in adult insects. The JHSB3 titer in the Sym-females were consistently higher compared to those of Apo-females. Since previous studies reported that Riptortus hexamerin-α and vitellogenin proteins were upregulated by the topical abdominal application of a JH-analog, chemically synthesized JHSB3 was administered to Apo-females. As expected, the hexamerin-α and vitellogenin proteins were dramatically increased in the hemolymph of JHSB3-treated Apo-females, resulting in increased egg production compared to that in Sym-females. Taken together, these results demonstrate that colonization of Burkholderia gut symbiont in the host insect stimulates biosynthesis of the heteroptera-specific JHSB3, leading to larger number of eggs produced and enhanced fitness in Riptortus host insects.
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Affiliation(s)
- Junbeom Lee
- Global Research Laboratory, College of Pharmacy, Pusan National University, Busan, 46241, South Korea
| | - Chan-Hee Kim
- Global Research Laboratory, College of Pharmacy, Pusan National University, Busan, 46241, South Korea
| | - Ho Am Jang
- Global Research Laboratory, College of Pharmacy, Pusan National University, Busan, 46241, South Korea
| | - Jiyeun Kate Kim
- Department of Microbiology, College of Medicine, Kosin University, Busan, 49267, South Korea
| | - Toyomi Kotaki
- National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, 305-8634, Japan
| | - Tetsuro Shinoda
- Faculty of Food and Agricultural Sciences Fukushima University, 1 Kanayagawa, Fukushima, 960-1248, Japan
| | - Tetsuro Shinada
- (e)Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan
| | - Jin-Wook Yoo
- Global Research Laboratory, College of Pharmacy, Pusan National University, Busan, 46241, South Korea
| | - Bok Luel Lee
- Global Research Laboratory, College of Pharmacy, Pusan National University, Busan, 46241, South Korea.
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20
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Garcia JR, Larsen TJ, Queller DC, Strassmann JE. Fitness costs and benefits vary for two facultative Burkholderia symbionts of the social amoeba, Dictyostelium discoideum. Ecol Evol 2019; 9:9878-9890. [PMID: 31534701 PMCID: PMC6745654 DOI: 10.1002/ece3.5529] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 06/19/2019] [Accepted: 07/02/2019] [Indexed: 12/18/2022] Open
Abstract
Hosts and their associated microbes can enter into different relationships, which can range from mutualism, where both partners benefit, to exploitation, where one partner benefits at the expense of the other. Many host-microbe relationships have been presumed to be mutualistic, but frequently only benefits to the host, and not the microbial symbiont, have been considered. Here, we address this issue by looking at the effect of host association on the fitness of two facultative members of the Dictyostelium discoideum microbiome (Burkholderia agricolaris and Burkholderia hayleyella). Using two indicators of bacterial fitness, growth rate and abundance, we determined the effect of D. discoideum on Burkholderia fitness. In liquid culture, we found that D. discoideum amoebas lowered the growth rate of both Burkholderia species. In soil microcosms, we tracked the abundance of Burkholderia grown with and without D. discoideum over a month and found that B. hayleyella had larger populations when associating with D. discoideum while B. agricolaris was not significantly affected. Overall, we find that both B. agricolaris and B. hayleyella pay a cost to associate with D. discoideum, but B. hayleyella can also benefit under some conditions. Understanding how fitness varies in facultative symbionts will help us understand the persistence of host-symbiont relationships. OPEN RESEARCH BADGES This article has earned an Open Data Badge for making publicly available the digitally-shareable data necessary to reproduce the reported results. The data is available at https://openscholarship.wustl.edu/data/15/.
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Affiliation(s)
- Justine R. Garcia
- Department of BiologyWashington University in St. LouisSt. LouisMOUSA
- Present address:
Department of BiologyNew Mexico Highlands UniversityLas VegasNMUSA
| | - Tyler J. Larsen
- Department of BiologyWashington University in St. LouisSt. LouisMOUSA
| | - David C. Queller
- Department of BiologyWashington University in St. LouisSt. LouisMOUSA
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21
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Established Cotton Stainer Gut Bacterial Mutualists Evade Regulation by Host Antimicrobial Peptides. Appl Environ Microbiol 2019; 85:AEM.00738-19. [PMID: 31028027 DOI: 10.1128/aem.00738-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 04/22/2019] [Indexed: 01/03/2023] Open
Abstract
Symbioses with microorganisms are ubiquitous in nature and confer important ecological traits to animal hosts but also require control mechanisms to ensure homeostasis of the symbiotic interactions. In addition to protecting hosts against pathogens, animal immune systems recognize, respond to, and regulate mutualists. The gut bacterial symbionts of the cotton stainer bug, Dysdercus fasciatus, elicit an immune response characterized by the upregulation of c-type lysozyme and the antimicrobial peptide pyrrhocoricin in bugs with their native gut microbiota compared to that in dysbiotic insects. In this study, we investigated the impact of the elicited antimicrobial immune response on the established cotton stainer gut bacterial symbiont populations. To this end, we used RNA interference (RNAi) to knock down immunity-related genes hypothesized to regulate the symbionts, and we subsequently measured the effect of this silencing on host fitness and on the abundance of the major gut bacterial symbionts. Despite successful downregulation of target genes by both ingestion and injection of double-stranded RNA (dsRNA), the silencing of immunity-related genes had no effect on either host fitness or the qualitative and quantitative composition of established gut bacterial symbionts, indicating that the host immune responses are not actively involved in the regulation of the nutritional and defensive gut bacterial mutualists. These results suggest that close associations of bacterial symbionts with their hosts can result in the evolution of mechanisms ensuring that symbionts remain insensitive to host immunological responses, which may be important for the evolutionary stability of animal-microbe symbiotic associations.IMPORTANCE Animal immune systems are central for the protection of hosts against enemies by preventing or eliminating successful infections. However, in the presence of beneficial bacterial mutualists, the immune system must strike a balance of not killing the beneficial symbionts while at the same time preventing enemy attacks. Here, using the cotton stainer bug, we reveal that its long-term associated bacterial symbionts are insensitive to the host's immune effectors, suggesting adaptation to the host's defenses, thereby strengthening the stability of the symbiotic relationship. The ability of the symbionts to elicit host immune responses but remain insensitive themselves may be a mechanism by which the symbionts prime hosts to fight future pathogenic infections.
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22
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Vetterli SU, Zerbe K, Müller M, Urfer M, Mondal M, Wang SY, Moehle K, Zerbe O, Vitale A, Pessi G, Eberl L, Wollscheid B, Robinson JA. Thanatin targets the intermembrane protein complex required for lipopolysaccharide transport in Escherichia coli. SCIENCE ADVANCES 2018; 4:eaau2634. [PMID: 30443594 PMCID: PMC6235536 DOI: 10.1126/sciadv.aau2634] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 10/16/2018] [Indexed: 05/31/2023]
Abstract
With the increasing resistance of many Gram-negative bacteria to existing classes of antibiotics, identifying new paradigms in antimicrobial discovery is an important research priority. Of special interest are the proteins required for the biogenesis of the asymmetric Gram-negative bacterial outer membrane (OM). Seven Lpt proteins (LptA to LptG) associate in most Gram-negative bacteria to form a macromolecular complex spanning the entire envelope, which transports lipopolysaccharide (LPS) molecules from their site of assembly at the inner membrane to the cell surface, powered by adenosine 5'-triphosphate hydrolysis in the cytoplasm. The periplasmic protein LptA comprises the protein bridge across the periplasm, which connects LptB2FGC at the inner membrane to LptD/E anchored in the OM. We show here that the naturally occurring, insect-derived antimicrobial peptide thanatin targets LptA and LptD in the network of periplasmic protein-protein interactions required to assemble the Lpt complex, leading to the inhibition of LPS transport and OM biogenesis in Escherichia coli.
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Affiliation(s)
- Stefan U. Vetterli
- Chemistry Department, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Katja Zerbe
- Chemistry Department, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Maik Müller
- Institute of Molecular Systems Biology and Department of Health Sciences and Technology, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Matthias Urfer
- Chemistry Department, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Milon Mondal
- Chemistry Department, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Shuang-Yan Wang
- Chemistry Department, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Kerstin Moehle
- Chemistry Department, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Oliver Zerbe
- Chemistry Department, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Alessandra Vitale
- Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland
| | - Gabriella Pessi
- Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland
| | - Leo Eberl
- Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland
| | - Bernd Wollscheid
- Institute of Molecular Systems Biology and Department of Health Sciences and Technology, ETH Zürich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - John A. Robinson
- Chemistry Department, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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23
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Dawadi B, Wang X, Xiao R, Muhammad A, Hou Y, Shi Z. PGRP-LB homolog acts as a negative modulator of immunity in maintaining the gut-microbe symbiosis of red palm weevil, Rhynchophorus ferrugineus Olivier. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 86:65-77. [PMID: 29715482 DOI: 10.1016/j.dci.2018.04.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 04/24/2018] [Accepted: 04/26/2018] [Indexed: 05/08/2023]
Abstract
Many notorious insect pests live in the symbiotic associations with gut microbiota. However, the mechanisms underlying how they host their gut microbiota are unknown. Most gut bacteria can release peptidoglycan (PGN) which is an important antigen to activate the immune response. Therefore, how to keep the appropriate gut immune intensity to host commensals while to efficiently remove enteropathogens is vital for insect health. This study is aimed at elucidating the roles of an amidase PGRP, Rf PGRP-LB, in maintaining the gut-microbe symbiosis of Red palm weevil (RPW), Rhynchophorus ferrugineus Olivier. RfPGRP-LB is a secreted protein containing a typical PGRP domain. The existence of five conservative amino acid residues, being required for amidase activity, showed that RfPGRP-LB is a catalytic protein. Expression analysis revealed abundance of RfPGRP-LB transcripts in gut was dramatically higher than those in other tissues. RfPGRP-LB could be significantly induced against the infection of Escherichia coli. In vitro assays revealed that rRfPGRP-LB impaired the growth of E. coli and agglutinated bacteria cells obviously, suggesting RfPGRP-LB is a pathogen recognition receptor and bactericidal molecule. RfPGRP-LB knockdown reduced the persistence of E. coli in gut and load of indigenous gut microbiota significantly. Furthermore, the community structure of indigenous gut microbiota was also intensively altered by RfPGRP-LB silence. Higher levels of the antimicrobial peptide, attacin, were detected in guts of RfPGRP-LB silenced larvae than controls. Collectively, RfPGRP-LB plays multiple roles in modulating the homeostasis of RPW gut microbiota not only by acting as a negative regulator of mucosal immunity through PGN degradation but also as a bactericidal effector to prevent overgrowth of commensals and persistence of noncommensals.
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Affiliation(s)
- Bishnu Dawadi
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fuzhou, 350002, China; Fujian Provincial Key Laboratory of Insect Ecology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xinghong Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fuzhou, 350002, China; Fujian Provincial Key Laboratory of Insect Ecology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Rong Xiao
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fuzhou, 350002, China; Fujian Provincial Key Laboratory of Insect Ecology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Abrar Muhammad
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fuzhou, 350002, China; Fujian Provincial Key Laboratory of Insect Ecology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Youming Hou
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fuzhou, 350002, China; Fujian Provincial Key Laboratory of Insect Ecology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
| | - Zhanghong Shi
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fuzhou, 350002, China; Fujian Provincial Key Laboratory of Insect Ecology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
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Tryptophan-Rich and Proline-Rich Antimicrobial Peptides. Molecules 2018; 23:molecules23040815. [PMID: 29614844 PMCID: PMC6017362 DOI: 10.3390/molecules23040815] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 03/29/2018] [Accepted: 03/30/2018] [Indexed: 12/25/2022] Open
Abstract
Due to the increasing emergence of drug-resistant pathogenic microorganisms, there is a world-wide quest to develop new-generation antibiotics. Antimicrobial peptides (AMPs) are small peptides with a broad spectrum of antibiotic activities against bacteria, fungi, protozoa, viruses and sometimes exhibit cytotoxic activity toward cancer cells. As a part of the native host defense system, most AMPs target the membrane integrity of the microorganism, leading to cell death by lysis. These membrane lytic effects are often toxic to mammalian cells and restrict their systemic application. However, AMPs containing predominantly either tryptophan or proline can kill microorganisms by targeting intracellular pathways and are therefore a promising source of next-generation antibiotics. A minimum length of six amino acids is required for high antimicrobial activity in tryptophan-rich AMPs and the position of these residues also affects their antimicrobial activity. The aromatic side chain of tryptophan is able to rapidly form hydrogen bonds with membrane bilayer components. Proline-rich AMPs interact with the 70S ribosome and disrupt protein synthesis. In addition, they can also target the heat shock protein in target pathogens, and consequently lead to protein misfolding. In this review, we will focus on describing the structures, sources, and mechanisms of action of the aforementioned AMPs.
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Lee SA, Jang SH, Kim BH, Shibata T, Yoo J, Jung Y, Kawabata SI, Lee BL. Insecticidal activity of the metalloprotease AprA occurs through suppression of host cellular and humoral immunity. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 81:116-126. [PMID: 29174605 DOI: 10.1016/j.dci.2017.11.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 11/22/2017] [Accepted: 11/22/2017] [Indexed: 06/07/2023]
Abstract
The biochemical characterization of virulence factors from entomopathogenic bacteria is important to understand entomopathogen-insect molecular interactions. Pseudomonas entomophila is a typical entomopathogenic bacterium that harbors virulence factors against several insects. However, the molecular actions of these factors against host innate immune responses are not clearly elucidated. In this study, we observed that bean bugs (Riptortus pedestris) that were injected with P. entomophila were highly susceptible to this bacterium. To determine how P. entomophila counteracts the host innate immunity to survive within the insect, we purified a highly enriched protein with potential host insect-killing activity from the culture supernatant of P. entomophila. Then, a 45-kDa protein was purified to homogeneity and identified as AprA which is an alkaline zinc metalloprotease of the genus Pseudomonas by liquid chromatography mass spectrometry (LC-MS). Purified AprA showed a pronounced killing effect against host insects and suppressed both host cellular and humoral innate immunity. Furthermore, to show that AprA is an important insecticidal protein of P. entomophila, we used an aprA-deficient P. entomophila mutant strain (ΔaprA). When ΔaprA mutant cells were injected to host insects, this mutant exhibited extremely attenuated virulence. In addition, the cytotoxicity against host hemocytes and the antimicrobial peptide-degrading ability of the ΔaprA mutant were greatly decreased. These findings suggest that AprA functions as an important insecticidal protein of P. entomophila via suppression of host cellular and humoral innate immune responses.
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Affiliation(s)
- Seung Ah Lee
- Global Research Laboratory of Insect Symbiosis, Pusan National University, Busan 46241, South Korea
| | - Seong Han Jang
- Global Research Laboratory of Insect Symbiosis, Pusan National University, Busan 46241, South Korea
| | - Byung Hyun Kim
- Global Research Laboratory of Insect Symbiosis, Pusan National University, Busan 46241, South Korea
| | - Toshio Shibata
- Institute for Advanced Study, Kyushu University, Fukuoka 819-0395, Japan; Graduate School of Systems Life Sciences, Kyushu University, Fukuoka 819-0395, Japan
| | - Jinwook Yoo
- College of Pharmacy, Pusan National University, Busan 46241, South Korea
| | - Yunjin Jung
- College of Pharmacy, Pusan National University, Busan 46241, South Korea
| | - Shun-Ichiro Kawabata
- Institute for Advanced Study, Kyushu University, Fukuoka 819-0395, Japan; Graduate School of Systems Life Sciences, Kyushu University, Fukuoka 819-0395, Japan
| | - Bok Luel Lee
- Global Research Laboratory of Insect Symbiosis, Pusan National University, Busan 46241, South Korea.
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