1
|
Gonçalves DDS, Hooker DJ, Dong Y, Baran N, Kyrylos P, Iturbe-Ormaetxe I, Simmons CP, O'Neill SL. Detecting wMel Wolbachia in field-collected Aedes aegypti mosquitoes using loop-mediated isothermal amplification (LAMP). Parasit Vectors 2019; 12:404. [PMID: 31416478 PMCID: PMC6694616 DOI: 10.1186/s13071-019-3666-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 08/10/2019] [Indexed: 12/12/2022] Open
Abstract
Background The World Mosquito Program uses Wolbachia pipientis for the biocontrol of arboviruses transmitted by Aedes aegypti mosquitoes. Diagnostic testing for Wolbachia in laboratory colonies and in field-caught mosquito populations has typically employed PCR. New, simpler methods to diagnose Wolbachia infection in mosquitoes are required for large-scale operational use. Methods Field-collected Ae. aegypti mosquitoes from North Queensland were tested using primers designed to detect the Wolbachia wsp gene, specific to the strain wMel. The results were analysed by colour change in the reaction mix. Furthermore, to confirm the efficiency of the LAMP assay, the results were compared to the gold-standard qPCR test. Results A novel loop-mediated isothermal amplification (LAMP) colorimetric test for the wMel strain of Wolbachia was designed, developed and validated for use in a high-throughput setting. Against the standard qPCR test, the analytical sensitivity, specificity and diagnostic metrics were: sensitivity (99.6%), specificity (92.2%), positive predictive value (97.08%) and negative predictive value (99.30%). Conclusions We describe an alternative, novel and high-throughput method for diagnosing wMel Wolbachia infections in mosquitoes. This assay should support Wolbachia surveillance in both laboratory and field populations of Ae. aegypti. Electronic supplementary material The online version of this article (10.1186/s13071-019-3666-6) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Daniela da Silva Gonçalves
- World Mosquito Program, Institute of Vector-Borne Disease, Monash University, 12 Innovation Walk, Clayton, VIC, 3800, Australia.
| | - David J Hooker
- World Mosquito Program, Institute of Vector-Borne Disease, Monash University, 12 Innovation Walk, Clayton, VIC, 3800, Australia
| | - Yi Dong
- World Mosquito Program, Institute of Vector-Borne Disease, Monash University, 12 Innovation Walk, Clayton, VIC, 3800, Australia
| | - Nathan Baran
- World Mosquito Program, Institute of Vector-Borne Disease, Monash University, 12 Innovation Walk, Clayton, VIC, 3800, Australia
| | - Peter Kyrylos
- World Mosquito Program, Institute of Vector-Borne Disease, Monash University, 12 Innovation Walk, Clayton, VIC, 3800, Australia
| | - Iñaki Iturbe-Ormaetxe
- World Mosquito Program, Institute of Vector-Borne Disease, Monash University, 12 Innovation Walk, Clayton, VIC, 3800, Australia
| | - Cameron P Simmons
- World Mosquito Program, Institute of Vector-Borne Disease, Monash University, 12 Innovation Walk, Clayton, VIC, 3800, Australia.,Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Scott L O'Neill
- World Mosquito Program, Institute of Vector-Borne Disease, Monash University, 12 Innovation Walk, Clayton, VIC, 3800, Australia
| |
Collapse
|
2
|
da Silva Gonçalves D, Iturbe-Ormaetxe I, Martins-da-Silva A, Telleria EL, Rocha MN, Traub-Csekö YM, O'Neill SL, Sant'Anna MRV, Moreira LA. Wolbachia introduction into Lutzomyia longipalpis (Diptera: Psychodidae) cell lines and its effects on immune-related gene expression and interaction with Leishmania infantum. Parasit Vectors 2019; 12:33. [PMID: 30646951 PMCID: PMC6332621 DOI: 10.1186/s13071-018-3227-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 11/21/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The leishmaniases are important neglected diseases caused by Leishmania spp. which are transmitted by sand flies, Lutzomyia longipalpis being the main vector of visceral leishmaniasis in the Americas. The methodologies for leishmaniasis control are not efficient, causing 1.5 million reported cases annually worldwide, therefore showing the need for development of novel strategies and interventions to control transmission of the disease. The bacterium Wolbachia pipientis is being used to control viruses transmitted by mosquitoes, such as dengue and Zika, and its introduction in disease vectors has been effective against parasites such as Plasmodium. Here we show the first successful establishment of Wolbachia into two different embryonic cell lines from L. longipalpis, LL-5 and Lulo, and analysed its effects on the sand fly innate immune system, followed by in vitro Leishmania infantum interaction. RESULTS Our results show that LL-5 cells respond to wMel and wMelPop-CLA strains within the first 72 h post-infection, through the expression of antimicrobial peptides and inducible nitric oxide synthase resulting in a decrease of Wolbachia detection in the early stages of infection. In subsequent passages, the wMel strain was not able to infect any of the sand fly cell lines while the wMelPop-CLA strain was able to stably infect Lulo cells and LL-5 at lower levels. In Wolbachia stably infected cells, the expression of immune-related genes involved with downregulation of the IMD, Toll and Jak-Stat innate immune pathways was significantly decreased, in comparison with the uninfected control, suggesting immune activation upon Wolbachia transinfection. Furthermore, Wolbachia transinfection did not promote a negative effect on parasite load in those cells. CONCLUSIONS Initial strong immune responses of LL5 cells might explain the inefficiency of stable infections in these cells while we found that Lulo cells are more permissive to infection with Wolbachia causing an effect on the cell immune system, but not against in vitro L. infantum interaction. This establishes Lulo cells as a good system for the adaptation of Wolbachia in L. longipalpis.
Collapse
Affiliation(s)
- Daniela da Silva Gonçalves
- Grupo Mosquitos Vetores: Endossimbiontes e Interação Patógeno Vetor, Centro de Pesquisas René Rachou - Fundação Oswaldo Cruz, Av. Augusto de Lima 1715, 30190-002. Belo Horizonte, Belo Horizonte, MG, Brazil
| | - Iñaki Iturbe-Ormaetxe
- World Mosquito Program, Institute of Vector-Borne Disease, Monash University, 12 Innovation Walk, Clayton, VIC, 3800, Australia
| | - Andrea Martins-da-Silva
- Laboratório de Biologia Molecular de Parasitos e Vetores, Instituto Oswaldo Cruz - Fundação Oswaldo Cruz, Av. Brasil, 4365, Rio de Janeiro, RJ, 21040-900, Brazil
| | - Erich Loza Telleria
- Laboratório de Biologia Molecular de Parasitos e Vetores, Instituto Oswaldo Cruz - Fundação Oswaldo Cruz, Av. Brasil, 4365, Rio de Janeiro, RJ, 21040-900, Brazil
| | - Marcele Neves Rocha
- Grupo Mosquitos Vetores: Endossimbiontes e Interação Patógeno Vetor, Centro de Pesquisas René Rachou - Fundação Oswaldo Cruz, Av. Augusto de Lima 1715, 30190-002. Belo Horizonte, Belo Horizonte, MG, Brazil
| | - Yara M Traub-Csekö
- Laboratório de Biologia Molecular de Parasitos e Vetores, Instituto Oswaldo Cruz - Fundação Oswaldo Cruz, Av. Brasil, 4365, Rio de Janeiro, RJ, 21040-900, Brazil
| | - Scott L O'Neill
- World Mosquito Program, Institute of Vector-Borne Disease, Monash University, 12 Innovation Walk, Clayton, VIC, 3800, Australia
| | - Maurício Roberto Viana Sant'Anna
- Laboratório de Insetos Hematófagos, Departamento de Parasitologia, Instituto de Ciências Biológicas/UFMG, Av. Antônio Carlos, 6627, 31270-901. Belo Horizonte, Belo Horizonte, MG, Brazil
| | - Luciano Andrade Moreira
- Grupo Mosquitos Vetores: Endossimbiontes e Interação Patógeno Vetor, Centro de Pesquisas René Rachou - Fundação Oswaldo Cruz, Av. Augusto de Lima 1715, 30190-002. Belo Horizonte, Belo Horizonte, MG, Brazil.
| |
Collapse
|
3
|
Fraser JE, De Bruyne JT, Iturbe-Ormaetxe I, Stepnell J, Burns RL, Flores HA, O’Neill SL. Novel Wolbachia-transinfected Aedes aegypti mosquitoes possess diverse fitness and vector competence phenotypes. PLoS Pathog 2017; 13:e1006751. [PMID: 29216317 PMCID: PMC5736235 DOI: 10.1371/journal.ppat.1006751] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 12/19/2017] [Accepted: 11/13/2017] [Indexed: 11/18/2022] Open
Abstract
Wolbachia pipientis from Drosophila melanogaster (wMel) is an endosymbiotic bacterium that restricts transmission of human pathogenic flaviviruses and alphaviruses, including dengue, Zika, and chikungunya viruses, when introduced into the mosquito vector Aedes aegypti. To date, wMel-infected Ae. aegypti have been released in field trials in 5 countries to evaluate the effectiveness of this strategy for disease control. Despite the success in establishing wMel-infected mosquitoes in wild populations, and the well-characterized antiviral capabilities of wMel, transinfecting different or additional Wolbachia strains into Ae. aegypti may improve disease impact, and perhaps more importantly, could provide a strategy to account for the possible evolution of resistant arboviruses. Here, we report the successful transinfection of Ae. aegypti with the Wolbachia strains wMelCS (D. melanogaster), wRi (D. simulans) and wPip (Culex quinquefasciatus) and assess the effects on Ae. aegypti fitness, cytoplasmic incompatibility, tissue tropism and pathogen blocking in a laboratory setting. The results demonstrate that wMelCS provides a similar degree of protection against dengue virus as wMel following an infectious blood meal, and significantly reduces viral RNA levels beyond that of wMel following a direct challenge with infectious virus in mosquitoes, with no additional fitness cost to the host. The protection provided by wRi is markedly weaker than that of wMelCS, consistent with previous characterisations of these lines in Drosophila, while wPip was found to substantially reduce the fitness of Ae. aegypti. Thus, we determine wMelCS as a key candidate for further testing in field-relevant fitness tests and viremic blood feeding challenges in a clinical setting to determine if it may represent an alternative Wolbachia strain with more desirable attributes than wMel for future field testing. Dengue viruses are transmitted by the Aedes aegypti mosquito, with an estimated 390 million human infections occurring per year worldwide. There is no approved antiviral therapeutic, and vaccines described so far have had limited efficacy. Recently, the endosymbiotic bacterium Wolbachia from Drosophila melanogaster (wMel) has been used to infect Ae. aegypti populations as a novel technology for reducing dengue virus transmission. Here we report the generation of three new mosquito lines infected with the Wolbachia strains wMelCS, wRi and wPip. Each line induced cytoplasmic incompatibility and was effectively maternally transmitted, as required for rapid spread through uninfected mosquito populations. Each Wolbachia strain was also found to reside in the salivary glands; a key tissue involved in viral transmission. Perhaps most importantly, wMelCS inhibited dengue virus replication and dissemination in mosquitoes following an infectious blood meal or intrathoracic injection, providing a similar level of protection as that described for wMel. wMelCS therefore warrants further investigation as a potential release strain in future field trials.
Collapse
Affiliation(s)
- Johanna E. Fraser
- Institute of Vector-Borne Disease, Monash University, Clayton, VIC, Australia
| | | | | | - Justin Stepnell
- Institute of Vector-Borne Disease, Monash University, Clayton, VIC, Australia
| | - Rhiannon L. Burns
- Institute of Vector-Borne Disease, Monash University, Clayton, VIC, Australia
| | - Heather A. Flores
- Institute of Vector-Borne Disease, Monash University, Clayton, VIC, Australia
| | - Scott L. O’Neill
- Institute of Vector-Borne Disease, Monash University, Clayton, VIC, Australia
- * E-mail:
| |
Collapse
|
4
|
Kemp DJ, Thomson FE, Edwards W, Iturbe-Ormaetxe I. Incomplete offspring sex bias in Australian populations of the butterfly Eurema hecabe. Heredity (Edinb) 2016; 118:284-292. [PMID: 27731327 DOI: 10.1038/hdy.2016.85] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 06/30/2016] [Accepted: 07/25/2016] [Indexed: 11/09/2022] Open
Abstract
Theory predicts unified sex ratios for most organisms, yet biases may be engendered by selfish genetic elements such as endosymbionts that kill or feminize individuals with male genotypes. Although rare, feminization is established for Wolbachia-infected Eurema butterflies. This paradigm is presently confined to islands in the southern Japanese archipelago, where feminized phenotypes produce viable all-daughter broods. Here, we characterize sex bias for E. hecabe in continental Australia. Starting with 186 wild-caught females, we reared >6000 F1-F3 progeny in pedigree designs that incorporated selective antibiotic treatments. F1 generations expressed a consistent bias across 2 years and populations that was driven by an ~5% incidence of broods comprising ⩾80% daughters. Females from biased lineages continued to overproduce daughters over two generations of outcrossing to wild males. Treatment with antibiotics of differential strength influenced sex ratio only in biased lineages by inducing an equivalent incomplete degree of son overproduction. Brood sex ratios were nevertheless highly variable within lineages and across generations. Intriguingly, the cytogenetic signature of female karyotype was uniformly absent, even among phenotypic females in unbiased lineages. Molecular evidence supported the existence of a single Wolbachia strain at high prevalence, yet this was not clearly linked to brood sex bias. In sum, we establish an inherited, experimentally reversible tendency for incomplete offspring bias. Key features of our findings clearly depart from the Japanese feminization paradigm and highlight the potential for more subtle degrees of sex distortion in arthropods.
Collapse
Affiliation(s)
- D J Kemp
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, New South Wales, Australia.,Centre for Tropical Environmental Sustainability Science and College of Science and Engineering, James Cook University, Cairns, Queensland, Australia
| | - F E Thomson
- Centre for Tropical Environmental Sustainability Science and College of Science and Engineering, James Cook University, Cairns, Queensland, Australia
| | - W Edwards
- Centre for Tropical Environmental Sustainability Science and College of Science and Engineering, James Cook University, Cairns, Queensland, Australia
| | - I Iturbe-Ormaetxe
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
| |
Collapse
|
5
|
Skelton E, Rancès E, Frentiu FD, Kusmintarsih ES, Iturbe-Ormaetxe I, Caragata EP, Woolfit M, O’Neill SL. A Native Wolbachia Endosymbiont Does Not Limit Dengue Virus Infection in the Mosquito Aedes notoscriptus (Diptera: Culicidae). J Med Entomol 2016; 53:401-8. [PMID: 26721865 PMCID: PMC5853675 DOI: 10.1093/jme/tjv235] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The endosymbiotic bacterium Wolbachia pipientis infects many species of insects and has been transinfected into the mosquito Aedes aegypti (L.), the primary vector of dengue virus (DENV). Recently, it has been shown that Wolbachia blocks the replication and transmission of RNA viruses, such as DENV, in a number of mosquito species including Ae. aegypti and Aedes albopictus (Skuse), which is naturally infected with Wolbachia and considered a secondary vector for DENV. The mosquito species Aedes notoscriptus (Skuse) is highly prevalent in Australia, including in areas where DENV outbreaks have been recorded. The mosquito has been implicated in the transmission of Ross River and Barmah Forest viruses, but not DENV. We investigated whether Wolbachia naturally infects this mosquito species and whether it has an impact on the ability of Ae. notoscriptus to transmit DENV. We show, for the first time, that Ae. notoscriptus is naturally infected with a strain of Wolbachia that belongs to supergroup B and is localized only in the ovaries. However, Wolbachia infection in Ae. notoscriptus did not induce resistance to DENV and had no effect on overall DENV infection rate or titer. The presence of a native Wolbachia in Ae. notoscriptus cannot explain why this mosquito is an ineffective vector of DENV.
Collapse
Affiliation(s)
- Ellie Skelton
- School of Biological Sciences, The University of Queensland, QLD 4072, Australia (
,
,
,
,
,
,
)
- School of Medicine, Deakin University, Geelong, VIC 3216, Australia (
)
| | - Edwige Rancès
- School of Biological Sciences, The University of Queensland, QLD 4072, Australia (
,
,
,
,
,
,
)
- School of Biological Sciences, Monash University, VIC 3800, Australia (
,
,
,
,
)
| | - Francesca D. Frentiu
- School of Biological Sciences, The University of Queensland, QLD 4072, Australia (
,
,
,
,
,
,
)
- School of Biomedical Sciences and Institute for Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, QLD 4059, Australia (
)
| | | | - Iñaki Iturbe-Ormaetxe
- School of Biological Sciences, The University of Queensland, QLD 4072, Australia (
,
,
,
,
,
,
)
- School of Biological Sciences, Monash University, VIC 3800, Australia (
,
,
,
,
)
| | - Eric P. Caragata
- School of Biological Sciences, The University of Queensland, QLD 4072, Australia (
,
,
,
,
,
,
)
- School of Biological Sciences, Monash University, VIC 3800, Australia (
,
,
,
,
)
- FIOCRUZ/ Centro de Pesquisas René Rachou, Belo Horizonte – MG Brazil CEP 30190-002 (
), and
| | - Megan Woolfit
- School of Biological Sciences, The University of Queensland, QLD 4072, Australia (
,
,
,
,
,
,
)
- School of Biological Sciences, Monash University, VIC 3800, Australia (
,
,
,
,
)
| | - Scott L. O’Neill
- School of Biological Sciences, The University of Queensland, QLD 4072, Australia (
,
,
,
,
,
,
)
- School of Biological Sciences, Monash University, VIC 3800, Australia (
,
,
,
,
)
- Corresponding author, e-mail:
| |
Collapse
|
6
|
Joubert DA, Walker T, Carrington LB, De Bruyne JT, Kien DHT, Hoang NLT, Chau NVV, Iturbe-Ormaetxe I, Simmons CP, O’Neill SL. Establishment of a Wolbachia Superinfection in Aedes aegypti Mosquitoes as a Potential Approach for Future Resistance Management. PLoS Pathog 2016; 12:e1005434. [PMID: 26891349 PMCID: PMC4758728 DOI: 10.1371/journal.ppat.1005434] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 01/11/2016] [Indexed: 12/20/2022] Open
Abstract
Wolbachia pipientis is an endosymbiotic bacterium estimated to chronically infect between 40-75% of all arthropod species. Aedes aegypti, the principle mosquito vector of dengue virus (DENV), is not a natural host of Wolbachia. The transinfection of Wolbachia strains such as wAlbB, wMel and wMelPop-CLA into Ae. aegypti has been shown to significantly reduce the vector competence of this mosquito for a range of human pathogens in the laboratory. This has led to wMel-transinfected Ae. aegypti currently being released in five countries to evaluate its effectiveness to control dengue disease in human populations. Here we describe the generation of a superinfected Ae. aegypti mosquito line simultaneously infected with two avirulent Wolbachia strains, wMel and wAlbB. The line carries a high overall Wolbachia density and tissue localisation of the individual strains is very similar to each respective single infected parental line. The superinfected line induces unidirectional cytoplasmic incompatibility (CI) when crossed to each single infected parental line, suggesting that the superinfection would have the capacity to replace either of the single constituent infections already present in a mosquito population. No significant differences in fitness parameters were observed between the superinfected line and the parental lines under the experimental conditions tested. Finally, the superinfected line blocks DENV replication more efficiently than the single wMel strain when challenged with blood meals from viremic dengue patients. These results suggest that the deployment of superinfections could be used to replace single infections and may represent an effective strategy to help manage potential resistance by DENV to field deployments of single infected strains.
Collapse
Affiliation(s)
- D. Albert Joubert
- School of Biological Sciences, Monash University, Clayton, Melbourne, Victoria, Australia
| | - Thomas Walker
- School of Biological Sciences, Monash University, Clayton, Melbourne, Victoria, Australia
| | - Lauren B. Carrington
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute, Parkville, Melbourne, Victoria, Australia
| | | | - Duong Hue T. Kien
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Nhat Le Thanh Hoang
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | | | - Iñaki Iturbe-Ormaetxe
- School of Biological Sciences, Monash University, Clayton, Melbourne, Victoria, Australia
| | - Cameron P. Simmons
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute, Parkville, Melbourne, Victoria, Australia
- * E-mail: (CPS); (SLO)
| | - Scott L. O’Neill
- School of Biological Sciences, Monash University, Clayton, Melbourne, Victoria, Australia
- * E-mail: (CPS); (SLO)
| |
Collapse
|
7
|
Nguyen TH, Nguyen HL, Nguyen TY, Vu SN, Tran ND, Le TN, Vien QM, Bui TC, Le HT, Kutcher S, Hurst TP, Duong TTH, Jeffery JAL, Darbro JM, Kay BH, Iturbe-Ormaetxe I, Popovici J, Montgomery BL, Turley AP, Zigterman F, Cook H, Cook PE, Johnson PH, Ryan PA, Paton CJ, Ritchie SA, Simmons CP, O'Neill SL, Hoffmann AA. Field evaluation of the establishment potential of wMelPop Wolbachia in Australia and Vietnam for dengue control. Parasit Vectors 2015; 8:563. [PMID: 26510523 PMCID: PMC4625535 DOI: 10.1186/s13071-015-1174-x] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 10/19/2015] [Indexed: 12/18/2022] Open
Abstract
Background Introduced Wolbachia bacteria can influence the susceptibility of Aedes aegypti mosquitoes to arboviral infections as well as having detrimental effects on host fitness. Previous field trials demonstrated that the wMel strain of Wolbachia effectively and durably invades Ae. aegypti populations. Here we report on trials of a second strain, wMelPop-PGYP Wolbachia, in field sites in northern Australia (Machans Beach and Babinda) and central Vietnam (Tri Nguyen, Hon Mieu Island), each with contrasting natural Ae. aegypti densities. Methods Mosquitoes were released at the adult or pupal stages for different lengths of time at the sites depending on changes in Wolbachia frequency as assessed through PCR assays of material collected through Biogents-Sentinel (BG-S) traps and ovitraps. Adult numbers were also monitored through BG-S traps. Changes in Wolbachia frequency were compared across hamlets or house blocks. Results Releases of adult wMelPop-Ae. aegypti resulted in the transient invasion of wMelPop in all three field sites. Invasion at the Australian sites was heterogeneous, reflecting a slower rate of invasion in locations where background mosquito numbers were high. In contrast, invasion across Tri Nguyen was relatively uniform. After cessation of releases, the frequency of wMelPop declined in all sites, most rapidly in Babinda and Tri Nguyen. Within Machans Beach the rate of decrease varied among areas, and wMelPop was detected for several months in an area with a relatively low mosquito density. Conclusions These findings highlight challenges associated with releasing Wolbachia-Ae. aegypti combinations with low fitness, albeit strong virus interference properties, as a means of sustainable control of dengue virus transmission. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-1174-x) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Tran Hien Nguyen
- National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam.
| | - H Le Nguyen
- National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam.
| | - Thu Yen Nguyen
- National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam.
| | - Sinh Nam Vu
- National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam.
| | - Nhu Duong Tran
- National Institute of Hygiene and Epidemiology, Hanoi, Viet Nam.
| | - T N Le
- Institute Pasteur, Nha Trang, Viet Nam.
| | | | - T C Bui
- Institute Pasteur, Nha Trang, Viet Nam.
| | - Huu Tho Le
- Khanh Hoa Health Department, Nha Trang, Viet Nam.
| | - Simon Kutcher
- Australian Foundation for Peoples of Asia and the Pacific Limited, Hanoi, Viet Nam.
| | - Tim P Hurst
- Australian Foundation for Peoples of Asia and the Pacific Limited, Hanoi, Viet Nam.
| | - T T H Duong
- Australian Foundation for Peoples of Asia and the Pacific Limited, Hanoi, Viet Nam.
| | | | | | - B H Kay
- QIMR Berghofer Medical Research Institute, Herston, Australia.
| | | | - Jean Popovici
- School of Biological Sciences, Monash University, Melbourne, Australia.
| | | | - Andrew P Turley
- School of Biological Sciences, Monash University, Melbourne, Australia.
| | - Flora Zigterman
- School of Biological Sciences, Monash University, Melbourne, Australia.
| | - Helen Cook
- School of Biological Sciences, Monash University, Melbourne, Australia.
| | - Peter E Cook
- School of Biological Sciences, Monash University, Melbourne, Australia.
| | - Petrina H Johnson
- School of Biological Sciences, Monash University, Melbourne, Australia.
| | - Peter A Ryan
- School of Biological Sciences, Monash University, Melbourne, Australia.
| | - Chris J Paton
- School of Public Health, Tropical Medicine and Rehabilitation Sciences, James Cook University, Smithfield, Australia.
| | - Scott A Ritchie
- School of Public Health, Tropical Medicine and Rehabilitation Sciences, James Cook University, Smithfield, Australia.
| | - Cameron P Simmons
- Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Viet Nam. .,Centre for Tropical Medicine, University of Oxford, Churchill Hospital, Oxford, UK. .,Department of Microbiology and Immunology, University of Melbourne, Parkville, Australia.
| | - Scott L O'Neill
- School of Biological Sciences, Monash University, Melbourne, Australia.
| | - Ary A Hoffmann
- Bio21 Institute and School of BioSciences, University of Melbourne, Parkville, Australia.
| |
Collapse
|
8
|
Woolfit M, Iturbe-Ormaetxe I, Brownlie JC, Walker T, Riegler M, Seleznev A, Popovici J, Rancès E, Wee BA, Pavlides J, Sullivan MJ, Beatson SA, Lane A, Sidhu M, McMeniman CJ, McGraw EA, O'Neill SL. Genomic evolution of the pathogenic Wolbachia strain, wMelPop. Genome Biol Evol 2014; 5:2189-204. [PMID: 24190075 PMCID: PMC3845649 DOI: 10.1093/gbe/evt169] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Most strains of the widespread endosymbiotic bacterium Wolbachia pipientis are benign or behave as reproductive parasites. The pathogenic strain wMelPop is a striking exception, however: it overreplicates in its insect hosts and causes severe life shortening. The mechanism of this pathogenesis is currently unknown. We have sequenced the genomes of three variants of wMelPop and of the closely related nonpathogenic strain wMelCS. We show that the genomes of wMelCS and wMelPop appear to be identical in the nonrepeat regions of the genome and differ detectably only by the triplication of a 19-kb region that is unlikely to be associated with life shortening, demonstrating that dramatic differences in the host phenotype caused by this endosymbiont may be the result of only minor genetic changes. We also compare the genomes of the original wMelPop strain from Drosophila melanogaster and two sequential derivatives, wMelPop-CLA and wMelPop-PGYP. To develop wMelPop as a novel biocontrol agent, it was first transinfected into and passaged in mosquito cell lines for approximately 3.5 years, generating wMelPop-CLA. This cell line-passaged strain was then transinfected into Aedes aegypti mosquitoes, creating wMelPop-PGYP, which was sequenced after 4 years in the insect host. We observe a rapid burst of genomic changes during cell line passaging, but no further mutations were detected after transinfection into mosquitoes, indicating either that host preadaptation had occurred in cell lines, that cell lines are a more selectively permissive environment than animal hosts, or both. Our results provide valuable data on the rates of genomic and phenotypic change in Wolbachia associated with host shifts over short time scales.
Collapse
Affiliation(s)
- Megan Woolfit
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Yeap HL, Axford JK, Popovici J, Endersby NM, Iturbe-Ormaetxe I, Ritchie SA, Hoffmann AA. Assessing quality of life-shortening Wolbachia-infected Aedes aegypti mosquitoes in the field based on capture rates and morphometric assessments. Parasit Vectors 2014; 7:58. [PMID: 24495395 PMCID: PMC4015819 DOI: 10.1186/1756-3305-7-58] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 01/29/2014] [Indexed: 01/13/2023] Open
Abstract
Background Recent releases have been carried out with Aedes aegypti mosquitoes infected with the wMelPop mosquito cell-line adapted (wMelPop-CLA) strain of Wolbachia. This infection introduced from Drosophila provides strong blockage of dengue and other arboviruses but also has large fitness costs in laboratory tests. The releases were used to evaluate the fitness of released infected mosquitoes, and (following termination of releases) to test for any effects of wMelPop-CLA on wing size and shape when mosquitoes were reared under field conditions. Methods We monitored gravid females via double sticky traps to assess the reproductive success of wMelPop-CLA-infected females and also sampled the overall mosquito population post-release using Biogent Sentinel traps. Morphometric analyses were used to evaluate infection effects on wing shape as well as size. Results Oviposition success as assessed through double sticky traps was unrelated to size of released mosquitoes. However, released mosquitoes with lower wing loading were more successful. Furthermore, wMelPop-CLA-infected mosquitoes had 38.3% of the oviposition success of uninfected mosquitoes based on the predicted infection frequency after release. Environmental conditions affected wing shape and particularly size across time in uninfected mosquitoes, but not in naturally-reared wMelPop-CLA-infected mosquitoes. Although the overall size and shape do not differ between naturally-reared wMelPop-CLA-infected and uninfected mosquitoes, the infected mosquitoes tended to have smaller wings than uninfected mosquitoes during the cooler November in comparison to December. Conclusion These results confirm the lower fitness of wMelPop-CLA infection under field conditions, helping to explain challenges associated with a successful invasion by this strain. In the long run, invasion may depend on releasing strains carrying insecticide resistance or egg desiccation resistance, combined with an active pre-release population suppression program.
Collapse
Affiliation(s)
- Heng Lin Yeap
- Pest and Disease Vector Group, Bio21 Institute and the Department of Genetics, University of Melbourne, Parkville, Victoria, Melbourne 3010, Australia.
| | | | | | | | | | | | | |
Collapse
|
10
|
Duplouy A, Iturbe-Ormaetxe I, Beatson SA, Szubert JM, Brownlie JC, McMeniman CJ, McGraw EA, Hurst GDD, Charlat S, O'Neill SL, Woolfit M. Draft genome sequence of the male-killing Wolbachia strain wBol1 reveals recent horizontal gene transfers from diverse sources. BMC Genomics 2013; 14:20. [PMID: 23324387 PMCID: PMC3639933 DOI: 10.1186/1471-2164-14-20] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 01/02/2013] [Indexed: 02/06/2023] Open
Abstract
Background The endosymbiont Wolbachia pipientis causes diverse and sometimes dramatic phenotypes in its invertebrate hosts. Four Wolbachia strains sequenced to date indicate that the constitution of the genome is dynamic, but these strains are quite divergent and do not allow resolution of genome diversification over shorter time periods. We have sequenced the genome of the strain wBol1-b, found in the butterfly Hypolimnas bolina, which kills the male offspring of infected hosts during embyronic development and is closely related to the non-male-killing strain wPip from Culex pipiens. Results The genomes of wBol1-b and wPip are similar in genomic organisation, sequence and gene content, but show substantial differences at some rapidly evolving regions of the genome, primarily associated with prophage and repetitive elements. We identified 44 genes in wBol1-b that do not have homologs in any previously sequenced strains, indicating that Wolbachia’s non-core genome diversifies rapidly. These wBol1-b specific genes include a number that have been recently horizontally transferred from phylogenetically distant bacterial taxa. We further report a second possible case of horizontal gene transfer from a eukaryote into Wolbachia. Conclusions Our analyses support the developing view that many endosymbiotic genomes are highly dynamic, and are exposed and receptive to exogenous genetic material from a wide range of sources. These data also suggest either that this bacterial species is particularly permissive for eukaryote-to-prokaryote gene transfers, or that these transfers may be more common than previously believed. The wBol1-b-specific genes we have identified provide candidates for further investigations of the genomic bases of phenotypic differences between closely-related Wolbachia strains.
Collapse
Affiliation(s)
- Anne Duplouy
- School of Biological Sciences, University of Queensland, 4072, Brisbane, QLD, Australia.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Riegler M, Iturbe-Ormaetxe I, Woolfit M, Miller WJ, O'Neill SL. Tandem repeat markers as novel diagnostic tools for high resolution fingerprinting of Wolbachia. BMC Microbiol 2012; 12 Suppl 1:S12. [PMID: 22375862 PMCID: PMC3287509 DOI: 10.1186/1471-2180-12-s1-s12] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Background Strains of the endosymbiotic bacterium Wolbachia pipientis are extremely diverse both genotypically and in terms of their induced phenotypes in invertebrate hosts. Despite extensive molecular characterisation of Wolbachia diversity, little is known about the actual genomic diversity within or between closely related strains that group tightly on the basis of existing gene marker systems, including Multiple Locus Sequence Typing (MLST). There is an urgent need for higher resolution fingerprinting markers of Wolbachia for studies of population genetics, horizontal transmission and experimental evolution. Results The genome of the wMel Wolbachia strain that infects Drosophila melanogaster contains inter- and intragenic tandem repeats that may evolve through expansion or contraction. We identified hypervariable regions in wMel, including intergenic Variable Number Tandem Repeats (VNTRs), and genes encoding ankyrin (ANK) repeat domains. We amplified these markers from 14 related Wolbachia strains belonging to supergroup A and were successful in differentiating size polymorphic alleles. Because of their tandemly repeated structure and length polymorphism, the markers can be used in a PCR-diagnostic multilocus typing approach, analogous to the Multiple Locus VNTR Analysis (MLVA) established for many other bacteria and organisms. The isolated markers are highly specific for supergroup A and not informative for other supergroups. However, in silico analysis of completed genomes from other supergroups revealed the presence of tandem repeats that are variable and could therefore be useful for typing target strains. Conclusions Wolbachia genomes contain inter- and intragenic tandem repeats that evolve through expansion or contraction. A selection of polymorphic tandem repeats is a novel and useful PCR diagnostic extension to the existing MLST typing system of Wolbachia, as it allows rapid and inexpensive high-throughput fingerprinting of closely related strains for which polymorphic markers were previously lacking.
Collapse
|
12
|
Hoffmann AA, Montgomery BL, Popovici J, Iturbe-Ormaetxe I, Johnson PH, Muzzi F, Greenfield M, Durkan M, Leong YS, Dong Y, Cook H, Axford J, Callahan AG, Kenny N, Omodei C, McGraw EA, Ryan PA, Ritchie SA, Turelli M, O'Neill SL. Successful establishment of Wolbachia in Aedes populations to suppress dengue transmission. Nature 2011; 476:454-7. [PMID: 21866160 DOI: 10.1038/nature10356] [Citation(s) in RCA: 905] [Impact Index Per Article: 69.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 07/06/2011] [Indexed: 01/26/2023]
Abstract
Genetic manipulations of insect populations for pest control have been advocated for some time, but there are few cases where manipulated individuals have been released in the field and no cases where they have successfully invaded target populations. Population transformation using the intracellular bacterium Wolbachia is particularly attractive because this maternally-inherited agent provides a powerful mechanism to invade natural populations through cytoplasmic incompatibility. When Wolbachia are introduced into mosquitoes, they interfere with pathogen transmission and influence key life history traits such as lifespan. Here we describe how the wMel Wolbachia infection, introduced into the dengue vector Aedes aegypti from Drosophila melanogaster, successfully invaded two natural A. aegypti populations in Australia, reaching near-fixation in a few months following releases of wMel-infected A. aegypti adults. Models with plausible parameter values indicate that Wolbachia-infected mosquitoes suffered relatively small fitness costs, leading to an unstable equilibrium frequency <30% that must be exceeded for invasion. These findings demonstrate that Wolbachia-based strategies can be deployed as a practical approach to dengue suppression with potential for area-wide implementation.
Collapse
Affiliation(s)
- A A Hoffmann
- Bio21 Institute, Department of Genetics, The University of Melbourne, Victoria 3010, Australia
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Walden PM, Heras B, Iturbe-Ormaetxe I, Inaba K, Martin JL. Functional studies on disulfide bond forming proteins of Wolbachia pipientis. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311080536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
14
|
Yamada R, Iturbe-Ormaetxe I, Brownlie JC, O'Neill SL. Functional test of the influence of Wolbachia genes on cytoplasmic incompatibility expression in Drosophila melanogaster. Insect Mol Biol 2011; 20:75-85. [PMID: 20854481 DOI: 10.1111/j.1365-2583.2010.01042.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Wolbachia are inherited intracellular bacteria that infect a broad range of invertebrate hosts. They commonly manipulate host reproduction in a variety of ways and thereby favour their invasion into host populations. While the biology of Wolbachia has been extensively studied at the ecological and phenotypic level, little is known about the molecular mechanisms underlying the interaction between Wolbachia and their hosts. Recent comparative genomics studies of Wolbachia strains have revealed putative candidate genes involved in the expression of cytoplasmic incompatibility (CI) in insects. However the functional testing of these genes is hindered by the lack of available genetic tools in Wolbachia. To circumvent this problem we generated transgenic Drosophila lines expressing various Wolbachia CI candidate genes under the control of the GAL4/UAS system in order to evaluate their possible role in Wolbachia-related phenotypes in Drosophila. The expression of a number of these genes in Drosophila melanogaster failed to mimic or alter CI phenotypes across a range of Wolbachia backgrounds or in the absence of Wolbachia.
Collapse
Affiliation(s)
- R Yamada
- School of Biological Sciences, The University of Queensland, Brisbane, Qld, Australia
| | | | | | | |
Collapse
|
15
|
Iturbe-Ormaetxe I, Woolfit M, Rancès E, Duplouy A, O'Neill SL. A simple protocol to obtain highly pure Wolbachia endosymbiont DNA for genome sequencing. J Microbiol Methods 2010; 84:134-6. [PMID: 21047535 DOI: 10.1016/j.mimet.2010.10.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 10/22/2010] [Accepted: 10/22/2010] [Indexed: 10/18/2022]
Abstract
Most genome sequencing projects using intracellular bacteria face difficulties in obtaining sufficient bacterial DNA free of host contamination. We have developed a simple and rapid protocol to isolate endosymbiont DNA virtually free from fly and mosquito host DNA. We purified DNA from six Wolbachia strains in preparation for genome sequencing using this method, and achieved up to 97% pure Wolbachia sequence, even after using frozen insects. This is a significant improvement for future Wolbachia and other endosymbiont genome projects.
Collapse
Affiliation(s)
- Iñaki Iturbe-Ormaetxe
- School of Biological Sciences, The University of Queensland, Brisbane, Qld 4072, Australia
| | | | | | | | | |
Collapse
|
16
|
Kurz M, Iturbe-Ormaetxe I, Jarrott R, Shouldice SR, Wouters MA, Frei P, Glockshuber R, O'Neill SL, Heras B, Martin JL. Structural and functional characterization of the oxidoreductase alpha-DsbA1 from Wolbachia pipientis. Antioxid Redox Signal 2009; 11:1485-500. [PMID: 19265485 DOI: 10.1089/ars.2008.2420] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The alpha-proteobacterium Wolbachia pipientis is a highly successful intracellular endosymbiont of invertebrates that manipulates its host's reproductive biology to facilitate its own maternal transmission. The fastidious nature of Wolbachia and the lack of genetic transformation have hampered analysis of the molecular basis of these manipulations. Structure determination of key Wolbachia proteins will enable the development of inhibitors for chemical genetics studies. Wolbachia encodes a homologue (alpha-DsbA1) of the Escherichia coli dithiol oxidase enzyme EcDsbA, essential for the oxidative folding of many exported proteins. We found that the active-site cysteine pair of Wolbachia alpha-DsbA1 has the most reducing redox potential of any characterized DsbA. In addition, Wolbachia alpha-DsbA1 possesses a second disulfide that is highly conserved in alpha-proteobacterial DsbAs but not in other DsbAs. The alpha-DsbA1 structure lacks the characteristic hydrophobic features of EcDsbA, and the protein neither complements EcDsbA deletion mutants in E. coli nor interacts with EcDsbB, the redox partner of EcDsbA. The surface characteristics and redox profile of alpha-DsbA1 indicate that it probably plays a specialized oxidative folding role with a narrow substrate specificity. This first report of a Wolbachia protein structure provides the basis for future chemical genetics studies.
Collapse
Affiliation(s)
- Mareike Kurz
- Institute for Molecular Bioscience, University of New South Wales, Sydney, Australia
| | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Woolfit M, Iturbe-Ormaetxe I, McGraw EA, O'Neill SL. An ancient horizontal gene transfer between mosquito and the endosymbiotic bacterium Wolbachia pipientis. Mol Biol Evol 2008; 26:367-74. [PMID: 18988686 DOI: 10.1093/molbev/msn253] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The extent and biological relevance of horizontal gene transfer (HGT) in eukaryotic evolution remain highly controversial. Recent studies have demonstrated frequent and large-scale HGT from endosymbiotic bacteria to their hosts, but the great majority of these transferred genes rapidly become nonfunctional in the recipient genome. Here, we investigate an ancient HGT between a host metazoan and an endosymbiotic bacterium, Wolbachia pipientis. The transferred gene has so far been found only in mosquitoes and Wolbachia. In mosquitoes, it is a member of a gene family encoding candidate receptors required for malaria sporozoite invasion of the mosquito salivary gland. The gene copy in Wolbachia has substantially diverged in sequence from the mosquito homolog, is evolving under purifying selection, and is expressed, suggesting that this gene is also functional in the bacterial genome. Several lines of evidence indicate that the gene may have been transferred from eukaryotic host to bacterial endosymbiont. Regardless of the direction of transfer, however, these results demonstrate that interdomain HGT may give rise to functional, persistent, and possibly evolutionarily significant new genes.
Collapse
Affiliation(s)
- Megan Woolfit
- School of Integrative Biology, University of Queensland, Brisbane, Australia
| | | | | | | |
Collapse
|
18
|
McMeniman CJ, Lane AM, Fong AWC, Voronin DA, Iturbe-Ormaetxe I, Yamada R, McGraw EA, O'Neill SL. Host adaptation of a Wolbachia strain after long-term serial passage in mosquito cell lines. Appl Environ Microbiol 2008; 74:6963-9. [PMID: 18836024 PMCID: PMC2583474 DOI: 10.1128/aem.01038-08] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Accepted: 09/22/2008] [Indexed: 11/20/2022] Open
Abstract
The horizontal transfer of the bacterium Wolbachia pipientis between invertebrate hosts hinges on the ability of Wolbachia to adapt to new intracellular environments. The experimental transfer of Wolbachia between distantly related host species often results in the loss of infection, presumably due to an inability of Wolbachia to adapt quickly to the new host. To examine the process of adaptation to a novel host, we transferred a life-shortening Wolbachia strain, wMelPop, from the fruit fly Drosophila melanogaster into a cell line derived from the mosquito Aedes albopictus. After long-term serial passage in this cell line, we transferred the mosquito-adapted wMelPop into cell lines derived from two other mosquito species, Aedes aegypti and Anopheles gambiae. After a prolonged period of serial passage in mosquito cell lines, wMelPop was reintroduced into its native host, D. melanogaster, by embryonic microinjection. The cell line-adapted wMelPop strains were characterized by a loss of infectivity when reintroduced into the original host, grew to decreased densities, and had reduced abilities to cause life-shortening infection and cytoplasmic incompatibility compared to the original strain. We interpret these shifts in phenotype as evidence for genetic adaptation to the mosquito intracellular environment. The use of cell lines to preadapt Wolbachia to novel hosts is suggested as a possible strategy to improve the success of transinfection in novel target insect species.
Collapse
Affiliation(s)
- Conor J McMeniman
- School of Integrative Biology, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Kurz M, Iturbe-Ormaetxe I, Jarrott R, Cowieson N, Robin G, Jones A, King GJ, Frei P, Glockshuber R, O'Neill SL, Heras B, Martin JL. Cloning, expression, purification and characterization of a DsbA-like protein from Wolbachia pipientis. Protein Expr Purif 2008; 59:266-73. [PMID: 18387819 DOI: 10.1016/j.pep.2008.02.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Revised: 02/07/2008] [Accepted: 02/13/2008] [Indexed: 11/19/2022]
Abstract
Wolbachia pipientis are obligate endosymbionts that infect a wide range of insect and other arthropod species. They act as reproductive parasites by manipulating the host reproduction machinery to enhance their own transmission. This unusual phenotype is thought to be a consequence of the actions of secreted Wolbachia proteins that are likely to contain disulfide bonds to stabilize the protein structure. In bacteria, the introduction or isomerization of disulfide bonds in proteins is catalyzed by Dsb proteins. The Wolbachia genome encodes two proteins, alpha-DsbA1 and alpha-DsbA2, that might catalyze these steps. In this work we focussed on the 234 residue protein alpha-DsbA1; the gene was cloned and expressed in Escherichia coli, the protein was purified and its identity confirmed by mass spectrometry. The sequence identity of alpha-DsbA1 for both dithiol oxidants (E. coli DsbA, 12%) and disulfide isomerases (E. coli DsbC, 14%) is similar. We therefore sought to establish whether alpha-DsbA1 is an oxidant or an isomerase based on functional activity. The purified alpha-DsbA1 was active in an oxidoreductase assay but had little isomerase activity, indicating that alpha-DsbA1 is DsbA-like rather than DsbC-like. This work represents the first successful example of the characterization of a recombinant Wolbachia protein. Purified alpha-DsbA1 will now be used in further functional studies to identify protein substrates that could help explain the molecular basis for the unusual Wolbachia phenotypes, and in structural studies to explore its relationship to other disulfide oxidoreductase proteins.
Collapse
Affiliation(s)
- Mareike Kurz
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld 4072, Australia
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Kurz M, Iturbe-Ormaetxe I, Jarrott R, O'Neill SL, Byriel KA, Martin JL, Heras B. Crystallization and preliminary diffraction analysis of a DsbA homologue from Wolbachia pipientis. Acta Crystallogr Sect F Struct Biol Cryst Commun 2008; 64:94-7. [PMID: 18259058 DOI: 10.1107/s1744309108000055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Accepted: 01/01/2008] [Indexed: 11/10/2022]
Abstract
alpha-DsbA1 is one of two DsbA homologues encoded by the Gram-negative alpha-proteobacterium Wolbachia pipientis, an endosymbiont that can behave as a reproductive parasite in insects and as a mutualist in medically important filarial nematodes. The alpha-DsbA1 protein is thought to be important for the folding and secretion of Wolbachia proteins involved in the induction of reproductive distortions. Crystals of native and SeMet alpha-DsbA1 were grown by vapour diffusion and belong to the monoclinic space group C2, with unit-cell parameters a = 71.4, b = 49.5, c = 69.3 A, beta = 107.0 degrees and one molecule in the asymmetric unit (44% solvent content). X-ray data were recorded from native crystals to a resolution of 2.01 A using a copper anode and data from SeMet alpha-DsbA1 crystals were recorded to 2.45 A resolution using a chromium anode.
Collapse
Affiliation(s)
- M Kurz
- Institute for Molecular Bioscience and ARC Special Research Centre for Functional and Applied Genomics, University of Queensland, St Lucia, QLD 4072, Australia
| | | | | | | | | | | | | |
Collapse
|
21
|
Iturbe-Ormaetxe I, O'Neill SL. Wolbachia–host interactions: connecting phenotype to genotype. Curr Opin Microbiol 2007; 10:221-4. [PMID: 17537669 DOI: 10.1016/j.mib.2007.05.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Revised: 04/09/2007] [Accepted: 05/14/2007] [Indexed: 01/23/2023]
Abstract
The long-established view of Wolbachia as reproductive parasites of insects is becoming complicated as an increasing number of papers describe a richer picture of Wolbachia-mediated phenotypes in insects. The search for the molecular basis for this phenotypic variability has been greatly aided by the recent sequencing of several Wolbachia genomes. These studies have revealed putative genes and pathways that are likely to be involved in the host-symbiont interaction. Whereas significant progress is being made from comparative genomic studies together with the use of model host systems like Drosophila, the ultimate linking of phenotype to genotype will require the development of genetic manipulation technology for both host and symbiont.
Collapse
Affiliation(s)
- Iñaki Iturbe-Ormaetxe
- School of Integrative Biology, The University of Queensland, St Lucia, QLD 4072, Brisbane, Australia
| | | |
Collapse
|
22
|
Cook PE, Hugo LE, Iturbe-Ormaetxe I, Williams CR, Chenoweth SF, Ritchie SA, Ryan PA, Kay BH, Blows MW, O'Neill SL. The use of transcriptional profiles to predict adult mosquito age under field conditions. Proc Natl Acad Sci U S A 2006; 103:18060-5. [PMID: 17110448 PMCID: PMC1838706 DOI: 10.1073/pnas.0604875103] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2006] [Indexed: 11/18/2022] Open
Abstract
Age is a critical determinant of an adult female mosquito's ability to transmit a range of human pathogens. Despite its central importance, relatively few methods exist with which to accurately determine chronological age of field-caught mosquitoes. This fact is a major constraint on our ability to fully understand the relative importance of vector longevity to disease transmission in different ecological contexts. It also limits our ability to evaluate novel disease control strategies that specifically target mosquito longevity. We report the development of a transcriptional profiling approach to determine age of adult female Aedes aegypti under field conditions. We demonstrate that this approach surpasses current cuticular hydrocarbon methods for both accuracy of predicted age as well as the upper limits at which age can be reliably predicted. The method is based on genes that display age-dependent expression in a range of dipteran insects and, as such, is likely to be broadly applicable to other disease vectors.
Collapse
Affiliation(s)
- Peter E. Cook
- *School of Integrative Biology, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Leon E. Hugo
- *School of Integrative Biology, University of Queensland, Brisbane, Queensland 4072, Australia
- Queensland Institute of Medical Research, Herston, Queensland 4029, Australia
| | - Iñaki Iturbe-Ormaetxe
- *School of Integrative Biology, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Craig R. Williams
- Anton Breinl Centre for Public Health and Tropical Medicine, James Cook University, Cairns, Queensland 4870, Australia; and
| | - Stephen F. Chenoweth
- *School of Integrative Biology, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Scott A. Ritchie
- Anton Breinl Centre for Public Health and Tropical Medicine, James Cook University, Cairns, Queensland 4870, Australia; and
- Tropical Population Health Unit, Queensland Health, Cairns, Queensland 4870, Australia
| | - Peter A. Ryan
- Queensland Institute of Medical Research, Herston, Queensland 4029, Australia
| | - Brian H. Kay
- Queensland Institute of Medical Research, Herston, Queensland 4029, Australia
| | - Mark W. Blows
- *School of Integrative Biology, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Scott L. O'Neill
- *School of Integrative Biology, University of Queensland, Brisbane, Queensland 4072, Australia
| |
Collapse
|
23
|
Abstract
The endosymbiotic bacterium Wolbachia pipientis infects a wide range of arthropods, in which it induces a variety of reproductive phenotypes, including cytoplasmic incompatibility (CI), parthenogenesis, male killing, and reversal of genetic sex determination. The recent sequencing and annotation of the first Wolbachia genome revealed an unusually high number of genes encoding ankyrin domain (ANK) repeats. These ANK genes are likely to be important in mediating the Wolbachia-host interaction. In this work we determined the distribution and expression of the different ANK genes found in the sequenced Wolbachia wMel genome in nine Wolbachia strains that induce different phenotypic effects in their hosts. A comparison of the ANK genes of wMel and the non-CI-inducing wAu Wolbachia strain revealed significant differences between the strains. This was reflected in sequence variability in shared genes that could result in alterations in the encoded proteins, such as motif deletions, amino acid insertions, and in some cases disruptions due to insertion of transposable elements and premature stops. In addition, one wMel ANK gene, which is part of an operon, was absent in the wAu genome. These variations are likely to affect the affinity, function, and cellular location of the predicted proteins encoded by these genes.
Collapse
Affiliation(s)
- Iñaki Iturbe-Ormaetxe
- School of Integrative Biology, The University of Queensland, St. Lucia, QLD 4072, Brisbane, Australia
| | | | | | | |
Collapse
|
24
|
Affiliation(s)
- Iñaki Iturbe-Ormaetxe
- School of Integrative Biology, The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
| | - Markus Riegler
- School of Integrative Biology, The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
| | - Scott L O'Neill
- School of Integrative Biology, The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
| |
Collapse
|
25
|
Iturbe-Ormaetxe I, Haralampidis K, Papadopoulou K, Osbourn AE. Molecular cloning and characterization of triterpene synthases from Medicago truncatula and Lotus japonicus. Plant Mol Biol 2003; 51:731-743. [PMID: 12683345 DOI: 10.1023/a:1022519709298] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Cloning of OSCs required for triterpene synthesis from legume species that are amenable to molecular genetics will provide tools to address the importance of triterpenes and their derivatives during normal plant growth and development and also in interactions with symbionts and pathogens. Here we report the cloning and characterization of a total of three triterpene synthases from the legume species Medicago truncatula and Lotus japonicus. These include a beta-amyrin synthase from M. truncatula (MtAMY1) and a mixed function triterpene synthase from Lotus japonicus (LjAMY2). A partial cDNA predicted to encode a beta-amyrin synthase (LjAMY1) was also isolated from L. japonicus. The expression patterns of MtAMY1, LjAMY1 and LjAMY2 and of additional triterpene synthases previously characterised from M. truncatula and pea differ in different plant tissues and during nodulation, suggesting that these enzymes may have distinct roles in plant physiology and development.
Collapse
|
26
|
Iturbe-Ormaetxe I, Heras B, Matamoros MA, Ramos J, Moran JF, Becana M. Cloning and functional characterization of a homoglutathione synthetase from pea nodules. Physiol Plant 2002; 115:69-73. [PMID: 12010468 DOI: 10.1034/j.1399-3054.2002.1150107.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The thiol tripeptide glutathione (GSH; gammaGlu-Cys-Gly) is very abundant in legume nodules where it performs multiple functions that are critical for optimal nitrogen fixation. Some legume nodules contain another tripeptide, homoglutathione (hGSH; gammaGlu-Cys-betaAla), in addition to or instead of GSH. We have isolated from a pea (Pisum sativum L.) nodule library a cDNA, GSHS2, that is expressed in nodules but not in leaves. This cDNA was overexpressed in insect cells and its protein product was identified as a highly active and specific hGSH synthetase. The enzyme, the first of this type to be completely purified, is predicted to be a homodimeric cytosolic protein. It shows a specific activity of 3400 nmol hGSH min-1 mg-1 protein with a standard substrate concentration (5 mM beta-alanine) and Km values of 1.9 mM for beta-alanine and 104 mM for glycine. The specificity constant (Vmax/Km) shows that the pure enzyme is 57.3-fold more specific for beta-alanine than for glycine. Southern blot analysis revealed that the gene is present as a single copy in the pea genome and that there are homologous genes in other legumes. We conclude that the synthesis of hGSH in pea nodules is catalysed by a specific hGSH synthetase and not by a GSH synthetase with broad substrate specificity.
Collapse
Affiliation(s)
- Iñaki Iturbe-Ormaetxe
- Departamento de Nutrición Vegetal, Estación Experimental de Aula Dei, Consejo Superior de Investigaciones Científicas, Apdo 202, ES-50080 Zaragoza, Spain
| | | | | | | | | | | |
Collapse
|
27
|
Abstract
The mitochondria of legume root nodules are critical to sustain the energy-intensive process of nitrogen fixation. They also generate reactive oxygen species at high rates and thus require the protection of antioxidant enzymes and metabolites. We show here that highly purified mitochondria from bean nodules (Phaseolus vulgaris L. cv. Contender x Rhizobium leguminosarum bv. phaseoli strain 3622) contain ascorbate peroxidase primarily in the inner membrane (with lesser amounts detected occasionally in the matrix), guaiacol peroxidases in the outer membrane and matrix, and manganese superoxide dismutase (MnSOD) and an ascorbate-regenerating system in the matrix. This regenerating system relies on homoglutathione (instead of glutathione) and pyridine nucleotides as electron donors and involves the enzymes monodehydroascorbate reductase, dehydroascorbate reductase, and homoglutathione reductase. Homoglutathione is synthesized in the cytosol and taken up by the mitochondria and bacteroids. Although bacteroids synthesize glutathione, it is not exported to the plant in significant amounts. We propose a model for the detoxification of peroxides in nodule mitochondria in which membrane-bound ascorbate peroxidase scavenges the peroxide formed by the electron transport chain using ascorbate provided by L-galactono-1,4-lactone dehydrogenase in the inner membrane. The resulting monodehydroascorbate and dehydroascorbate can be recycled in the matrix or cytosol. In the matrix, the peroxides formed by oxidative reactions and by MnSOD may be scavenged by specific isozymes of guaiacol peroxidase, ascorbate peroxidase, and catalase.
Collapse
Affiliation(s)
- I Iturbe-Ormaetxe
- Departamento de Nutrición Vegetal, Estación Experimental de Aula Dei, CSIC, Zaragoza, Spain
| | | | | | | | | |
Collapse
|
28
|
Moran JF, Iturbe-Ormaetxe I, Matamoros MA, Rubio MC, Clemente MR, Brewin NJ, Becana M. Glutathione and homoglutathione synthetases of legume nodules. Cloning, expression, and subcellular localization. Plant Physiol 2000; 124:1381-92. [PMID: 11080313 PMCID: PMC59235 DOI: 10.1104/pp.124.3.1381] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2000] [Accepted: 08/07/2000] [Indexed: 05/18/2023]
Abstract
The thiol tripeptides glutathione (GSH) and homoglutathione (hGSH) are very abundant in legume root nodules and their synthesis is catalyzed by the enzymes gamma-glutamylcysteine synthetase (gammaECS), GSH synthetase (GSHS), and hGSH synthetase (hGSHS). As an essential step to elucidate the role of thiols in N(2) fixation we have isolated cDNAs encoding the three enzymes and have quantified the transcripts in nodules. Assay of enzyme activities in highly purified nodule organelles revealed that gammaECS is localized in the plastids, hGSHS in the cytosol, and GSHS in the cytosol and mitochondria. These results are consistent with sequence analyses. Subcellular fractionation of nodules also showed that bacteroids contain high thiol concentrations and high specific gammaECS and GSHS activities. Results emphasize the role of nodule plastids in antioxidant protection and in control of thiol synthesis, and suggest that plastids may be important in the stress response of nodules. Overall, our results provide further evidence that thiol synthesis is critical for nodule functioning.
Collapse
Affiliation(s)
- J F Moran
- Departamento de Nutrición Vegetal, Estación Experimental de Aula Dei, Consejo Superior de Investigaciones Científicas, Apdo 202, 50080 Zaragoza, Spain
| | | | | | | | | | | | | |
Collapse
|
29
|
Matamoros MA, Moran JF, Iturbe-Ormaetxe I, Rubio MC, Becana M. Glutathione and homoglutathione synthesis in legume root nodules. Plant Physiol 1999; 121:879-88. [PMID: 10557236 PMCID: PMC59450 DOI: 10.1104/pp.121.3.879] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/1999] [Accepted: 07/21/1999] [Indexed: 05/19/2023]
Abstract
High-performance liquid chromatography (HPLC) with fluorescence detection was used to study thiol metabolism in legume nodules. Glutathione (GSH) was the major non-protein thiol in all indeterminate nodules examined, as well as in the determinate nodules of cowpea (Vigna unguiculata), whereas homoglutathione (hGSH) predominated in soybean (Glycine max), bean (Phaseolus vulgaris), and mungbean (Vigna radiata) nodules. All nodules had greater thiol concentrations than the leaves and roots of the same plants because of active thiol synthesis in nodule tissue. The correlation between thiol tripeptides and the activities of glutathione synthetase (GSHS) and homoglutathione synthetase (hGSHS) in the nodules of eight legumes, and the contrasting thiol contents and activities in alfalfa (Medicago sativa) leaves (98% hGSH, 100% hGSHS) and nodules (72% GSH, 80% GSHS) indicated that the distribution of GSH and hGSH is determined by specific synthetases. Thiol contents and synthesis decreased with both natural and induced nodule senescence, and were also reduced in the senescent zone of indeterminate nodules. Thiols and GSHS were especially abundant in the meristematic and infected zones of pea (Pisum sativum) nodules. Thiols and gamma-glutamylcysteinyl synthetase were also more abundant in the infected zone of bean nodules, but hGSHS was predominant in the cortex. Isolation of full-length cDNA sequences coding for gamma-glutamylcysteinyl synthetase from legume nodules revealed that they are highly homologous to those from other higher plants.
Collapse
Affiliation(s)
- M A Matamoros
- Departamento de Nutrición Vegetal, Estación Experimental de Aula Dei, Consejo Superior de Investigaciones Científicas, Apdo 202, 50080 Zaragoza, Spain
| | | | | | | | | |
Collapse
|
30
|
Matamoros MA, Baird LM, Escuredo PR, Dalton DA, Minchin FR, Iturbe-Ormaetxe I, Rubio MC, Moran JF, Gordon AJ, Becana M. Stress-induced legume root nodule senescence. Physiological, biochemical, and structural alterations. Plant Physiol 1999; 121:97-112. [PMID: 10482665 PMCID: PMC59394 DOI: 10.1104/pp.121.1.97] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/1999] [Accepted: 06/02/1999] [Indexed: 05/18/2023]
Abstract
Nitrate-fed and dark-stressed bean (Phaseolus vulgaris) and pea (Pisum sativum) plants were used to study nodule senescence. In bean, 1 d of nitrate treatment caused a partially reversible decline in nitrogenase activity and an increase in O(2) diffusion resistance, but minimal changes in carbon metabolites, antioxidants, and other biochemical parameters, indicating that the initial decrease in nitrogenase activity was due to O(2) limitation. In pea, 1 d of dark treatment led to a 96% decline in nitrogenase activity and sucrose, indicating sugar deprivation as the primary cause of activity loss. In later stages of senescence (4 d of nitrate or 2-4 d of dark treatment), nodules showed accumulation of oxidized proteins and general ultrastructural deterioration. The major thiol tripeptides of untreated nodules were homoglutathione (72%) in bean and glutathione (89%) in pea. These predominant thiols declined by approximately 93% after 4 d of nitrate or dark treatment, but the loss of thiol content can be only ascribed in part to limited synthesis by gamma-glutamylcysteinyl, homoglutathione, and glutathione synthetases. Ascorbate peroxidase was immunolocalized primarily in the infected and parenchyma (inner cortex) nodule cells, with large decreases in senescent tissue. Ferritin was almost undetectable in untreated bean nodules, but accumulated in the plastids and amyloplasts of uninfected interstitial and parenchyma cells following 2 or 4 d of nitrate treatment, probably as a response to oxidative stress.
Collapse
Affiliation(s)
- M A Matamoros
- Departamento de Nutrición Vegetal, Estación Experimental de Aula Dei, Consejo Superior de Investigaciones Científicas, Apdo 202, 50080 Zaragoza, Spain
| | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Dalton DA, Joyner SL, Becana M, Iturbe-Ormaetxe I, Chatfield JM. Antioxidant defenses in the peripheral cell layers of legume root nodules. Plant Physiol 1998; 116:37-43. [PMID: 9449834 PMCID: PMC35178 DOI: 10.1104/pp.116.1.37] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/1997] [Accepted: 09/18/1997] [Indexed: 05/19/2023]
Abstract
Ascorbate peroxidase (AP) is a key enzyme that scavenges potentially harmful H2O2 and thus prevents oxidative damage in plants, especially in N2-fixing legume root nodules. The present study demonstrates that the nodule endodermis of alfalfa (Medicago sativa) root nodules contains elevated levels of AP protein, as well as the corresponding mRNA transcript and substrate (ascorbate). Enhanced AP protein levels were also found in cells immediately peripheral to the infected region of soybean (Glycine max), pea (Pisum sativum), clover (Trifolium pratense), and common bean (Phaseolus vulgaris) nodules. Regeneration of ascorbate was achieved by (homo)glutathione and associated enzymes of the ascorbate-glutathione pathway, which were present at high levels. The presence of high levels of antioxidants suggests that respiratory consumption of O2 in the endodermis or nodule parenchyma may be an essential component of the O2-diffusion barrier that regulates the entry of O2 into the central region of nodules and ensures optimal functioning of nitrogenase.
Collapse
Affiliation(s)
- D A Dalton
- Biology Department, Reed College, Portland, Oregon 97202, USA.
| | | | | | | | | |
Collapse
|
32
|
Escuredo PR, Minchin FR, Gogorcena Y, Iturbe-Ormaetxe I, Klucas RV, Becana M. Involvement of Activated Oxygen in Nitrate-Induced Senescence of Pea Root Nodules. Plant Physiol 1996; 110:1187-1195. [PMID: 12226252 PMCID: PMC160906 DOI: 10.1104/pp.110.4.1187] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The effect of short-term nitrate application (10 mM, 0-4 d) on nitrogenase (N2ase) activity, antioxidant defenses, and related parameters was investigated in pea (Pisum sativum L. cv Frilene) nodules. The response of nodules to nitrate comprised two stages. In the first stage (0-2 d), there were major decreases in N2ase activity and N2ase-linked respiration and concomitant increases in carbon cost of N2ase and oxygen diffusion resistance of nodules. There was no apparent oxidative damage, and the decline in N2ase activity was, to a certain extent, reversible. The second stage (>2 d) was typical of a senescent, essentially irreversible process. It was characterized by moderate increases in oxidized proteins and catalytic Fe and by major decreases in antioxidant enzymes and metabolites. The restriction in oxygen supply to bacteroids may explain the initial decline in N2ase activity. The decrease in antioxidant protection is not involved in this process and is not specifically caused by nitrate, since it also occurs with drought stress. However, comparison of nitrate- and drought-induced senescence shows an important difference: there is no lipid degradation or lipid peroxide accumulation with nitrate, indicating that lipid peroxidation is not necessarily involved in nodule senescence.
Collapse
Affiliation(s)
- P. R. Escuredo
- Departamento de Nutricion Vegetal, Estacion Experimental de Aula Dei, Consejo Superior de Investigaciones Cientificas, Apdo 202, 50080 Zaragoza, Spain (P.R.E., Y.G., I.I.-O., R.V.K., M.B.)
| | | | | | | | | | | |
Collapse
|
33
|
Gogorcena Y, Iturbe-Ormaetxe I, Escuredo PR, Becana M. Antioxidant Defenses against Activated Oxygen in Pea Nodules Subjected to Water Stress. Plant Physiol 1995; 108:753-759. [PMID: 12228507 PMCID: PMC157397 DOI: 10.1104/pp.108.2.753] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The involvement of activated oxygen in the drought-induced damage of pea (Pisum sativum L. cv Frilene) nodules was examined. To this purpose, various pro-oxidant factors, antioxidant enzymes and related metabolites, and markers of oxidative damage were determined in nodules of well-watered (nodule water potential approximately -0.29 MPa) and water-stressed (nodule water potential approximately -2.03 MPa) plants. Water-stressed nodules entered senescence as evidenced by the 30% decrease in leghemoglobin and total soluble protein. Drought also caused a decrease in the activities of catalase (25%), ascorbate peroxidase (18%), dehydroascorbate reductase (15%), glutathione reductase (31%), and superoxide dismutase (30%), and in the contents of ascorbate (59%), reduced (57%) and oxidized (38%) glutathione, NAD+ and NADH (43%), NADP+ (31%), and NADPH (17%). The decline in the antioxidant capacity of nodules may result from a restricted supply of NAD(P)H in vivo for the ascorbate-glutathione pathway and from the Fe-catalyzed Fenton reactions of ascorbate and glutathione with activated oxygen. The 2-fold increase in the content of "catalytic Fe" would also explain the augmented levels of lipid peroxides (2.4-fold) and oxidatively modified proteins (1.4-fold) found in water-stressed nodules because of the known requirement of lipid and protein oxidation for a transition catalytic metal.
Collapse
Affiliation(s)
- Y. Gogorcena
- Departamento de Nutricion Vegetal, Estacion Experimental de Aula Dei, Consejo Superior de Investigaciones Cientificas, Apdo 202, 50080 Zaragoza, Spain
| | | | | | | |
Collapse
|