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Saab SA, Zhang X, Zeineddine S, Morejon B, Michel K, Osta MA. Insight into the structural hierarchy of the protease cascade that regulates the mosquito melanization response. Microbes Infect 2024; 26:105245. [PMID: 37918462 PMCID: PMC10872705 DOI: 10.1016/j.micinf.2023.105245] [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: 08/01/2023] [Revised: 10/18/2023] [Accepted: 10/30/2023] [Indexed: 11/04/2023]
Abstract
Serine protease cascades regulate important insect immune responses, including melanization and Toll pathway activation. In the context of melanization, central components of these cascades are clip domain serine proteases (CLIPs) including the catalytic, clip domain serine proteases (cSPs) and their non-catalytic homologs (cSPHs). Here, we define partially the structural hierarchy of An. gambiae cSPs of the CLIPB family, central players in melanization, and characterize their relative contributions to bacterial melanization and to mosquito susceptibility to bacterial infections. Using in vivo genetic analysis we show that the protease cascade branches downstream of the cSPs CLIPB4 and CLIPB17 into two branches one converging on CLIPB10 and the second on CLIPB8. We also show that the contribution of key cSPHs to melanization in vivo in response to diverse microbial challenges is more significant than any of the individual cSPs, possibly due to partial functional redundancy among the latter. Interestingly, we show that the key cSPH CLIPA8 which is essential for the efficient activation cleavage of CLIPBs in vivo is efficiently cleaved itself by several CLIPBs in vitro, suggesting that cSPs and cSPHs regulate signal amplification and propagation in melanization cascades by providing positive reinforcement upstream and downstream of each other.
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Affiliation(s)
- Sally A Saab
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Xiufeng Zhang
- Division of Biology, Kansas State University, Manhattan, KS, USA
| | - Suheir Zeineddine
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Bianca Morejon
- Division of Biology, Kansas State University, Manhattan, KS, USA
| | - Kristin Michel
- Division of Biology, Kansas State University, Manhattan, KS, USA
| | - Mike A Osta
- Department of Biology, American University of Beirut, Beirut, Lebanon.
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Saab SA, Zhang X, Zeineddine S, Morejon B, Michel K, Osta MA. Insight into the structural hierarchy of the protease cascade that regulates the mosquito melanization response. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.13.548954. [PMID: 37503117 PMCID: PMC10369957 DOI: 10.1101/2023.07.13.548954] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Serine protease cascades regulate important insect immune responses, including melanization and Toll pathway activation. In the context of melanization, central components of these cascades are clip domain serine proteases (CLIPs) including the catalytic, clip domain serine proteases (cSPs) and their non-catalytic homologs (cSPHs). Here, we define partially the structural hierarchy of An. gambiae cSPs of the CLIPB family, central players in melanization, and characterize their relative contributions to bacterial melanization and to mosquito susceptibility to bacterial infections. Using in vivo genetic analysis we show that the protease cascade branches downstream of the cSPs CLIPB4 and CLIPB17 into two branches one converging on CLIPB10 and the second on CLIPB8. We also show that the contribution of key cSPHs to melanization in vivo in response to diverse microbial challenges is more significant than any of the individual cSPs, possibly due to partial functional redundancy among the latter. Interestingly, we show that the key cSPH CLIPA8 which is essential for the efficient activation cleavage of CLIPBs in vivo is efficiently cleaved itself by several CLIPBs in vitro, suggesting that cSPs and cSPHs regulate signal amplification and propagation in melanization cascades by providing positive reinforcement upstream and downstream of each other.
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Affiliation(s)
- Sally A. Saab
- Department of Biology, American University of Beirut, Beirut, Lebanon
- Present address: Department of Molecular Microbiology and Immunology, Johns Hopkins University, Baltimore, USA
| | - Xiufeng Zhang
- Division of Biology, Kansas State University, Manhattan, KS, USA
| | - Suheir Zeineddine
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Bianca Morejon
- Division of Biology, Kansas State University, Manhattan, KS, USA
| | - Kristin Michel
- Division of Biology, Kansas State University, Manhattan, KS, USA
| | - Mike A. Osta
- Department of Biology, American University of Beirut, Beirut, Lebanon
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3
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Qin Y, Liu X, Peng G, Xia Y, Cao Y. Recent Advancements in Pathogenic Mechanisms, Applications and Strategies for Entomopathogenic Fungi in Mosquito Biocontrol. J Fungi (Basel) 2023; 9:746. [PMID: 37504734 PMCID: PMC10381795 DOI: 10.3390/jof9070746] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 07/11/2023] [Accepted: 07/11/2023] [Indexed: 07/29/2023] Open
Abstract
Fungal diseases are widespread among insects and play a crucial role in naturally regulating insect populations. Mosquitoes, known as vectors for numerous infectious diseases, pose a significant threat to human health. Entomopathogenic fungi (EPF) have emerged as highly promising alternative agents to chemical mosquitocides for controlling mosquitoes at all stages of their life cycle due to their unique infection pathway through direct contact with the insect's cuticle. In recent years, significant advancements have been made in understanding the infection pathways and pathogenic mechanisms of EPF against mosquitoes. Various strategies involving the use of EPF alone or combinations with other approaches have been employed to target mosquitoes at various developmental stages. Moreover, the application of genetic technologies in fungi has opened up new avenues for enhancing the mosquitocidal efficacy of EPF. This review presents a comprehensive summary of recent advancements in our understanding the pathogenic mechanisms of EPF, their applications in mosquito management, and the combination of EPF with other approaches and employment of transgenic technologies. The biosafety concerns associated with their use and the corresponding approaches are also discussed. The recent progress suggests that EPF have the potential to serve as a future biorational tool for controlling mosquito vectors.
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Affiliation(s)
- Yujie Qin
- School of Life Sciences, Chongqing University, Chongqing 401331, China
- Chongqing Engineering Research Center for Fungal Insecticides, Chongqing 401331, China
- Key Laboratory of Gene Function and Regulation Technologies, Chongqing Municipal Education Commission, Chongqing 401331, China
| | - Xiaoyu Liu
- School of Life Sciences, Chongqing University, Chongqing 401331, China
- Chongqing Engineering Research Center for Fungal Insecticides, Chongqing 401331, China
- Key Laboratory of Gene Function and Regulation Technologies, Chongqing Municipal Education Commission, Chongqing 401331, China
| | - Guoxiong Peng
- School of Life Sciences, Chongqing University, Chongqing 401331, China
- Chongqing Engineering Research Center for Fungal Insecticides, Chongqing 401331, China
- Key Laboratory of Gene Function and Regulation Technologies, Chongqing Municipal Education Commission, Chongqing 401331, China
| | - Yuxian Xia
- School of Life Sciences, Chongqing University, Chongqing 401331, China
- Chongqing Engineering Research Center for Fungal Insecticides, Chongqing 401331, China
- Key Laboratory of Gene Function and Regulation Technologies, Chongqing Municipal Education Commission, Chongqing 401331, China
| | - Yueqing Cao
- School of Life Sciences, Chongqing University, Chongqing 401331, China
- Chongqing Engineering Research Center for Fungal Insecticides, Chongqing 401331, China
- Key Laboratory of Gene Function and Regulation Technologies, Chongqing Municipal Education Commission, Chongqing 401331, China
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Vidhate RP, Dawkar VV, Punekar SA, Giri AP. Genomic Determinants of Entomopathogenic Fungi and Their Involvement in Pathogenesis. MICROBIAL ECOLOGY 2023; 85:49-60. [PMID: 34977966 DOI: 10.1007/s00248-021-01936-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 11/24/2021] [Indexed: 06/14/2023]
Abstract
Entomopathogenic fungi offer an effective and eco-friendly alternative to curb insect populations in biocontrol strategy. The evolutionary history of selected entomopathogenic fungi indicates their ancestral relationship with plant endophytes. During this host shifting, entomopathogenic fungi must have acquired multiple mechanisms, including a combination of various biomolecules that make them distinguishable from other fungi. In this review, we focus on understanding various biochemical and molecular mechanisms involved in entomopathogenesis. In particular, we attempt to explain the indispensable role of enlarged gene families of various virulent factors, viz. chitinases, proteases, lipases, specialized metabolites, and cytochrome P450, in entomopathogenesis. Our analysis suggests that entomopathogenic fungi recruit a different set of gene products during the progression of pathogenesis. Knowledge of these bio-molecular interactions between fungi and insect hosts will allow researchers to execute pointed efforts towards the development of improved entomopathogenic fungal strains.
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Affiliation(s)
- Ravindra P Vidhate
- Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, 411008, Maharashtra, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, Uttar Pradesh, India
| | - Vishal V Dawkar
- Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, 411008, Maharashtra, India
| | - Sachin A Punekar
- Biospheres, Eshwari, 52/403, Lakshminagar, Parvati, Pune, 411009, Maharashtra, India
| | - Ashok P Giri
- Plant Molecular Biology Unit, Division of Biochemical Sciences, CSIR-National Chemical Laboratory, Pune, 411008, Maharashtra, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, Uttar Pradesh, India.
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Zakhia R, Osta MA. CLIPA7 Exhibits Pleiotropic Roles in the Anopheles gambiae Immune Response. J Innate Immun 2022; 15:317-332. [PMID: 36423593 PMCID: PMC10643895 DOI: 10.1159/000526486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 08/09/2022] [Indexed: 10/30/2023] Open
Abstract
Clip domain serine proteases and clip domain serine protease homologs (cSPHs) are key components of serine protease cascades that drive the melanization response. Despite lacking catalytic activity, cSPHs play essential roles in regulating melanization, but the spectrum of functions they catalyze within and outside these cascades is not fully understood. Aside from their classical role as cofactors for PPO activation, we have previously revealed an unprecedented complexity in the function and molecular organization of these cSPHs in the immune response of the malaria vector Anopheles gambiae. Here, we add yet another dimension to the complex roles underpinning the contributions of cSPHs to mosquito immunity by showing that CLIPA7, a member of the expanded cSPH family, defines a novel branch within the cSPH network that is essential for the melanization of Escherichia coli but not Plasmodium ookinetes or Gram-positive bacteria. Despite its dispensability for the melanization of Gram-positive bacteria, we show that CLIPA7 is required for the clearance of systemic infections with Staphylococcus aureus. CLIPA7 is produced by hemocytes and associates with the surfaces of live E. coli and S. aureus cells in vivo as well as with those of melanized cells. Based on its RNAi phenotypes and its unique domain architecture among A. gambiae cSPHs including the presence of an RGD motif, we propose that CLIPA7 exhibits pleiotropic roles in mosquito immunity that extend beyond the regulation of melanization to microbial clearance.
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Affiliation(s)
| | - Mike A. Osta
- Department of Biology, American University of Beirut, Beirut, Lebanon
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Wang H, Peng H, Li W, Cheng P, Gong M. The Toxins of Beauveria bassiana and the Strategies to Improve Their Virulence to Insects. Front Microbiol 2021; 12:705343. [PMID: 34512581 PMCID: PMC8430825 DOI: 10.3389/fmicb.2021.705343] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/27/2021] [Indexed: 01/18/2023] Open
Abstract
The long-term and excessive usage of pesticides is an enormous burden on the environment, which also increases pest resistance. To overcome this problem, research and application of entomopathogenic fungi, which are both environmentally friendly and cause lower resistance, have gained great momentum. Entomopathogenic fungi have a wide range of prospects. Apart from Bacillus thuringiensis, Beauveria bassiana is the most studied biopesticide. After invading insect hosts, B. bassiana produces a variety of toxins, which are secondary metabolites such as beauvericin, bassianin, bassianolide, beauverolides, tenellin, oosporein, and oxalic acid. These toxins help B. bassiana to parasitize and kill the hosts. This review unequivocally considers beauveria toxins highly promising and summarizes their attack mechanism(s) on the host insect immune system. Genetic engineering strategies to improve toxin principles, genes, or virulent molecules of B. bassiana have also been discussed. Lastly, we discuss the future perspective of Beauveria toxin research, including newly discovered toxins.
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Affiliation(s)
- Haiyang Wang
- Shandong Institute of Parasitic Diseases, Shandong First Medical University & Shandong Academy of Medical Sciences, Jining, China.,College of Forensic Medicine and Laboratory Medicine, Jining Medical University, Jining, China
| | - Hui Peng
- Shandong Institute of Parasitic Diseases, Shandong First Medical University & Shandong Academy of Medical Sciences, Jining, China
| | - Wenjuan Li
- College of Forensic Medicine and Laboratory Medicine, Jining Medical University, Jining, China
| | - Peng Cheng
- Shandong Institute of Parasitic Diseases, Shandong First Medical University & Shandong Academy of Medical Sciences, Jining, China
| | - Maoqing Gong
- Shandong Institute of Parasitic Diseases, Shandong First Medical University & Shandong Academy of Medical Sciences, Jining, China
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Koodalingam A, Dayanidhi MK. Studies on biochemical and synergistic effects of immunosuppressive concentration of imidacloprid with Beauveria bassiana and Metarhizium anisopliae for enhancement of virulence against vector mosquito Culex quinquefasciatus. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2021; 176:104882. [PMID: 34119224 DOI: 10.1016/j.pestbp.2021.104882] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 05/13/2021] [Accepted: 05/19/2021] [Indexed: 06/12/2023]
Abstract
In order to increase the virulence of two commonly used entomopathogens namely Beauveria bassiana and Metarhizium anisopliae for effective mosquito control programs, we developed new combined formulation by the use of immunosuppressive concentration of imidacloprid. Exposure of sublethal concentration (LC10 1.34 ppb) of imidacloprid to second instar larvae for 92 h that differently modulated the larval biochemical markers by decreasing the total protein (20.65% reduction), acetylcholinesterase (35.74% reduction) and increases the β-carboxylesterase (26.59% increase) and acid phosphatase (30.69% increase) levels while no significant difference was noticed in alkaline phosphatase of C. quinquefasciatus. Further we demonstrated that the imidacloprid exposure brings about reduction in phenoloxidase level (39.48% decrease) and nitric oxide production (37.64% decrease) in larval homogenate over control. The reduction in viability of hemocytes (15.37% decrease) and phagocytic activity of hemocytes (32.18% decrease) was noticed in imidacloprid treatment. Moreover in laboratory condition, exposure of 1 × 107 spores/ml of B. bassiana (984) and M. anisopliae (6060) alone for 92 h cumulative toxicity assay exhibited larval mortality of 36.47% and 47.64% respectively against C. quinquefasciatus. However in the synergistic experimental studies with LC10 of imidacloprid and 1 × 107 spores/ml of B. bassiana or M. anisopliae to the larvae for 92 h cumulative assay brought 60% and 50.59% more insecticidal activity than the respective entomopathogens alone. The substantial increase of larvicidal activity noticed in the synergistic test conditions against larvae of C. quinquefasciatus revealed that the inclusion of sublethal concentration was proved to be useful for effective larval control.
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Affiliation(s)
- Arunagirinathan Koodalingam
- PG & Research Department of Zoology, Sir Theagaraya College, Old Washermenpet, Chennai 600 021, Tamil Nadu, India.
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Huang W, Huang Y, Hao Y, Huang S, Gao T, Keyhani NO, Huang Z. Host-dependent contributions of the Cfcdp1 protease gene to virulence in the entomopathogenic fungus Cordyceps fumosorosea. PEST MANAGEMENT SCIENCE 2020; 76:575-588. [PMID: 31287229 DOI: 10.1002/ps.5549] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 06/26/2019] [Accepted: 07/05/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND The genomes of broad host range insect pathogenic fungi, including Cordyceps fumosorosea, encode for a suite of secreted proteases implicated in targeting, penetration, and degradation of the host exoskeleton or cuticle. These cuticle-degrading proteases act as critical virulence factors, but their functions within the biological context, particularly in relation to host specificity, remain poorly characterized. RESULT A C. fumosorosea protease gene, Cfcdp1, was identified and a targeted gene-knockout strain constructed. Minor growth defects were observed for the ΔCfcdp1 strain when compared to the wild-type parent and complemented (ΔCfcdp1::Cfcdp1) strains, with delayed and decreased sporulation noted for the mutant. Decreased subtilisin-like protease activity was seen for the ΔCfcdp1 strain, although total secreted protease activity was similar between the mutant and wild-type strains. Insect bioassays using whitefly, Bemisia tabaci, and cabbageworm, Pieris rapae, showed decreased infectivity, i.e. 2.4-3.4-fold increase in lethal dose (LC50 ) and an increased time to death (LT50 ), for the ΔCfcdp1 strain. In contrast, insect bioassays using the diamondback moth, Plutella xylostella, or the brown planthopper, Nilaparvata lugens, showed increased infectivity, i.e. a 3-5-fold decrease in LC50 , and a decreased LT50 . Differential effects were also seen on the fecundity of B. tabaci infected by the different fungal strains. CONCLUSION These data reveal host-dependent effects of a protease implicated in cuticle degradation on C. fumosorosea virulence. The implications of these findings in suggesting context-dependent requirements of cuticle-degrading enzymes and their potentially differential roles in mediating virulence towards different hosts are discussed. © 2019 Society of Chemical Industry.
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Affiliation(s)
- Wenyou Huang
- College of Agriculture, South China Agricultural University, Guangzhou, China
| | - Yü Huang
- College of Agriculture, South China Agricultural University, Guangzhou, China
| | - Yongfen Hao
- College of Agriculture, South China Agricultural University, Guangzhou, China
| | - Song Huang
- College of Agriculture, South China Agricultural University, Guangzhou, China
- Guangzhou Institute for Food Inspection, Guangzhou, China
| | - Tianni Gao
- College of Agriculture, South China Agricultural University, Guangzhou, China
| | - Nemat O Keyhani
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, USA
| | - Zhen Huang
- College of Agriculture, South China Agricultural University, Guangzhou, China
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, USA
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El Moussawi L, Nakhleh J, Kamareddine L, Osta MA. The mosquito melanization response requires hierarchical activation of non-catalytic clip domain serine protease homologs. PLoS Pathog 2019; 15:e1008194. [PMID: 31765430 PMCID: PMC6901238 DOI: 10.1371/journal.ppat.1008194] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 12/09/2019] [Accepted: 11/05/2019] [Indexed: 12/20/2022] Open
Abstract
Serine protease cascades regulate important insect immune responses namely melanization and Toll pathway activation. An important component of these cascades are clip-domain serine protease homologs (cSPHs), which are non-catalytic, but essential for activating the enzyme prophenoloxidase (PPO) in the melanization response during septic infections. The activation of cSPHs requires their proteolytic cleavage, yet factors that control their activation and the complexity of their interactions within these cascades remain unclear. Here, we report the identification of CLIPA28 as a novel immune-related cSPH in the malaria vector Anopheles gambiae. Functional genetic analysis using RNA interference (RNAi) revealed that CLIPA28 is essential for the melanization of Plasmodium berghei parasites in refractory mosquitoes, and for mosquito resistance to fungal infections. We further show, using combined biochemical and genetic approaches, that CLIPA28 is member of a network of at least four cSPHs, whereby members are activated in a hierarchical manner following septic infections. Depletion of the complement-like protein TEP1 abolished the activation of this network after septic infections, whereas, depletion of the serine protease inhibitor 2 (SRPN2) triggered enhanced network activation, even in naïve mosquitoes, culminating in a dramatic reduction in cSPHs hemolymph levels, which paralleled that of PPO. Our data suggest that cSPHs are engaged in complex and multilayered interactions within serine protease cascades that regulate melanization, and identify TEP1 and SRPN2 as two master regulators of the cSPH network. Melanization is a spectacular immune response of insects that culminates in the deposition of melanin on microbial surfaces leading to their death. Despite more than half a century of investigation of this immune reaction in several insect models, important knowledge gaps, specifically concerning the regulation of this response, remain, especially that its output is tightly regulated by complex genetic and biochemical interactions between members of structurally diverse immune gene families. Here, we identify a new hemolymph protein that is involved in the melanization of malaria parasites and show that it forms, together with other proteins of the same gene family, a network, whereby members are activated in an orderly manner during mosquito septic infections. Furthemore, we show that this network is controlled by two structurally distinct immune proteins which act as master regulators of its activation. Dissecting the complexity of the regulatory mechanisms mediating insect melanization responses, may facilitate fine manipulation of mosquito immunity to reduce vectorial capacity.
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Affiliation(s)
- Layla El Moussawi
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Johnny Nakhleh
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | | | - Mike A. Osta
- Department of Biology, American University of Beirut, Beirut, Lebanon
- * E-mail:
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10
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Lovett B, Bilgo E, Diabate A, St Leger R. A review of progress toward field application of transgenic mosquitocidal entomopathogenic fungi. PEST MANAGEMENT SCIENCE 2019; 75:2316-2324. [PMID: 30801913 DOI: 10.1002/ps.5385] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 02/02/2019] [Accepted: 02/18/2019] [Indexed: 06/09/2023]
Abstract
In Africa, adult mosquito populations are primarily controlled with insecticide-impregnated bed nets and residual insecticide sprays. This coupled with widespread applications of pesticides in agriculture has led to increasing insecticide resistance in mosquito populations. We have developed multiple alternative strategies for exploiting transgenic Metarhizium spp. directed at: (i) shortening the lifespan of adult mosquitoes; (ii) reducing transmission potential of Plasmodium spp.; (iii) reducing vector competence via pre-lethal effects. The present challenge is to convert this promising strategy into a validated public health intervention by resolving outstanding issues related to the release of genetically modified organisms. © 2019 Society of Chemical Industry.
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Affiliation(s)
- Brian Lovett
- Department of Entomology, University of Maryland, College Park, MD, USA
| | - Etienne Bilgo
- Institut de Recherche en Sciences de la Santé/Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Abdoulaye Diabate
- Institut de Recherche en Sciences de la Santé/Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Raymond St Leger
- Department of Entomology, University of Maryland, College Park, MD, USA
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11
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Expression of Bacillus thuringiensis toxin Cyt2Ba in the entomopathogenic fungus Beauveria bassiana increases its virulence towards Aedes mosquitoes. PLoS Negl Trop Dis 2019; 13:e0007590. [PMID: 31306427 PMCID: PMC6667155 DOI: 10.1371/journal.pntd.0007590] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 07/30/2019] [Accepted: 06/30/2019] [Indexed: 11/23/2022] Open
Abstract
Background The entomopathogenic fungus Beauveria bassiana has been widely used to kill mosquito larvae and adults in the laboratory and field. However, its slow action of killing has hampered its widespread application. In our study, the B. bassiana fungus was genetically modified to express the Bacillus thuringiensis (Bt) toxin Cyt2Ba to improve its efficacy in killing mosquitoes. Methodology/Principal findings The efficacy of the wild type (WT) of B. bassiana and a transgenic strain expressing Cyt2Ba toxin (Bb-Cyt2Ba) was evaluated against larval and adult Aedes mosquitoes (Aedes aegypti and Aedes albopictus) using insect bioassays. The Bb-Cyt2Ba displayed increased virulence against larval and adult Aedes mosquitoes compared with the WT: for Ae. aegypti adults, the median lethal time (LT50) was decreased by 33% at the concentration of 1× 108 conidia/ml, 19% at 1× 107 conidia/ml and 47% at 1× 106 conidia/ml. The LT50 for Ae. albopictus adults was reduced by 20%, 23% and 29% at the same concentrations, respectively. The LT50 for Ae. aegypti larvae was decreased by 42% at 1× 107 conidia/ml and 25% at 1× 106 conidia/ml, and that for Ae. albopictus larvae was reduced by 33% and 31% at the same concentrations, respectively. In addition, infection with Bb-Cyt2Ba resulted in a dramatic reduction in the fecundity of Aedes mosquitoes. Conclusions/Significance In conclusion, our study demonstrated that the virulence of B. bassiana against mosquitoes can be significantly improved by introducing the Bt toxin gene Cyt2Ba into the genome to express the exogenous toxin in the fungus. The transgenic strain Bb-Cyt2Ba significantly reduced the survival and fecundity of Ae. aegypti and Ae. albopictus compared with the WT strain, which suggested that this recombinant B. bassiana has great potential for use in mosquito control. Mosquito vectors transmit many diseases to humans and animals, causing illness and death and resulting in substantial socio-economic burdens in endemic countries. The control of mosquitoes has almost exclusively relied on the use of chemical insecticides, which has recently led to the broad resistance of important mosquito vectors worldwide. Entomopathogenic fungi, such as Beauveria bassiana, are an important alternative or complement to chemical insecticides. However, the relatively slow action of fungal pathogens in killing mosquitoes, compared with chemical insecticides, has hampered their widespread application. To improve the insecticidal efficacy of the entomopathogen B. bassiana, the fungus was genetically modified to express the Bacillus thuringiensis toxin Cyt2Ba. The mitotically stable transformant (Bb-Cyt2Ba) successfully expressed Cyt2Ba toxin, and the virulence of this strain against adults and larvae of Aedes aegypti and Aedes albopictus mosquitoes was significantly improved. In addition, egg laying was significantly affected by Bb-Cyt2Ba infection. Infection with this fungus resulted in a dramatic reduction in fecundity of the target mosquitoes. Therefore, this recombinant B. bassiana has great potential for use in mosquito control.
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12
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Deng SQ, Cai QD, Deng MZ, Huang Q, Peng HJ. Scorpion neurotoxin AaIT-expressing Beauveria bassiana enhances the virulence against Aedes albopictus mosquitoes. AMB Express 2017; 7:121. [PMID: 28605881 PMCID: PMC5466577 DOI: 10.1186/s13568-017-0422-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 06/01/2017] [Indexed: 11/10/2022] Open
Abstract
To improve the insecticidal efficacy of this entomopathogen Beauveria bassiana, the fungus was genetically modified to express an insect-specific scorpion neurotoxin AaIT. The virulence of the recombinant B. bassiana strain (Bb-AaIT) against Aedes albopictus adults (which occurs via penetration through the cuticle during spore germination or by conidia ingestion), and the larvae (by conidia ingestion) was measured with bioassays. The median lethal concentration (LC50) of Bb-AaIT against A. albopictus larvae was 313.3-fold lower on day 4 and 11.3-fold lower on day 10 than that of the wild type (WT). Through conidia feeding or body contact, Bb-AaIT killed 50% of adult female mosquitoes at 3.9- or 1.9-fold reduced concentrations on day 4 and at 2.1- or 2.4-fold reduced concentrations on day 10. Compared with the results for the WT, the median lethal time (LT50) of Bb-AaIT was reduced by 28.6% at 1 × 107 conidia ml-1 and 34.3% at 1 × 106 conidia ml-1 in the larvae bioassay by conidia ingestion, while it decreased 32.3% at 1 × 107 conidia ml-1 by conidia ingestion and 24.2% at 1 × 108 conidia ml-1 by penetrating through the cuticle in the adult bioassay. All the differences were significant. Our findings indicated that Bb-AaIT had higher virulence and faster action than the WT in killing the larval and adult mosquitoes, and therefore, it is valuable for development as a commercial mosquito pesticide.
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Affiliation(s)
- Sheng-Qun Deng
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, and Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, School of Public Health, Southern Medical University, Guangzhou, 510515 Guangdong Province China
| | - Qun-Di Cai
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, and Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, School of Public Health, Southern Medical University, Guangzhou, 510515 Guangdong Province China
| | - Ming-Zhi Deng
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, and Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, School of Public Health, Southern Medical University, Guangzhou, 510515 Guangdong Province China
| | - Qiang Huang
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, and Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, School of Public Health, Southern Medical University, Guangzhou, 510515 Guangdong Province China
| | - Hong-Juan Peng
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, and Key Laboratory of Prevention and Control for Emerging Infectious Diseases of Guangdong Higher Institutes, School of Public Health, Southern Medical University, Guangzhou, 510515 Guangdong Province China
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13
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Valero-Jiménez CA, van Kan JAL, Koenraadt CJM, Zwaan BJ, Schoustra SE. Experimental evolution to increase the efficacy of the entomopathogenic fungus Beauveria bassiana against malaria mosquitoes: Effects on mycelial growth and virulence. Evol Appl 2017; 10:433-443. [PMID: 28515777 PMCID: PMC5427670 DOI: 10.1111/eva.12451] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 11/18/2016] [Indexed: 02/04/2023] Open
Abstract
Entomopathogenic fungi such as Beauveria bassiana are currently considered as a potential control agent for malaria mosquitoes. The success of such strategies depends among others on the efficacy of the fungus to kill its hosts. As B. bassiana can use various resources for growth and reproduction, increasing the dependency on mosquitoes as a nutritional source may be instrumental for reaching this goal. Passage of entomopathogenic fungi through an insect host has been shown to increase its virulence. We evaluated the virulence, fungal outgrowth, mycelial growth rate, and sporulation rate of two B. bassiana isolates (Bb1520 and Bb8028) that underwent 10 consecutive selection cycles through malaria mosquitoes (Anopheles coluzzii) using an experimental evolution approach. This cycling resulted in an altered capacity of evolved B. Bassiana lineages to grow on different substrates while maintaining the ability to kill insects. Notably, however, there were no significant changes in virulence or speed of outgrowth when comparing the evolved lineages against their unevolved ancestors. These results suggest that fungal growth and sporulation evolved through successive and exclusive use of an insect host as a nutritional resource. We discuss the results in light of biocontrol and provide suggestions to increase fungal virulence.
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Affiliation(s)
- Claudio A Valero-Jiménez
- Laboratory of Genetics Wageningen University Wageningen The Netherlands.,Laboratory of Entomology Wageningen University Wageningen The Netherlands
| | - Jan A L van Kan
- Laboratory of Phytopathology Wageningen University Wageningen The Netherlands
| | | | - Bas J Zwaan
- Laboratory of Genetics Wageningen University Wageningen The Netherlands
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14
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Kweka EJ, Lee MC, Mwang'onde BJ, Tenu F, Munga S, Kimaro EE, Himeidan YE. Bio-efficacy of deltamethrin based durable wall lining against wild populations of Anopheles gambiae s.l. in Northern Tanzania. BMC Res Notes 2017; 10:92. [PMID: 28187779 PMCID: PMC5303249 DOI: 10.1186/s13104-017-2414-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 02/02/2017] [Indexed: 11/18/2022] Open
Abstract
Background Indoor residual spraying (IRS) is one of the preferred tools used for control of malaria in many settings in the world. However, this control tool still faces challenges that include lack of long lasting active ingredient, limited number of well-trained personal, and need of repeated treatment which increases operational costs and reduces acceptability by residents. As a result there is need to develop and validate other methods which can complement the existing controls. The current study compared the bio-efficacy of durable wall lining (DL) (treated with deltamethrin 265 mg/m2) and IRS (with deltamethrin 5% WP at 20 mg/m2) on indoor mosquitoes densities and biting behaviour of mosquitoes in comparison with control houses without either DL or IRS. Methods A study with two treatment arms and a control was conducted in Magugu ward, Northern Tanzania. Overall, a total of 60 houses were selected for the study with 20 houses per treatment arm and control. From each arm and control five houses were selected for mosquitoes trapping. Mosquitoes were sampled from 18:00 to 07:00 hourly every month for a period of 6 months. Mosquitoes were sampled using CDC miniature light traps. Results A total of 14,400 female wild mosquitoes were used for contact bioassays in the control arm. 20 houses were sprayed, additionally walls of 20 houses were installed with wall liners, and walls of 20 unsprayed houses were used as control. Also, a total of 946 mosquitoes were sampled with traps in 60 houses during the hourly sampling for 6 months. A total of 3000 unfed females of An. gambiae s.l. wild population raised from larvae were collected from natural habitats in the same village for bioassays. The decline in indoor mosquitoes densities observed in this study did not lead to a shift in the biting cycles (P = 0.712). The number of mosquitoes caught indoors in houses with DL and IRS was significantly lower (P < 0.001) compared to control houses. When the comparisons were done between DL and IRS houses, the densities were significantly lower in DL houses compared to IRS houses (P = 0.021). In the DL installed houses, indoor mosquito density declined notably and sustained throughout the 6 months of the study. However, in those houses sprayed with deltamethrin 5% WP (PALI™5 WP), the density noted to start to increase within four months after spraying(do you mean to say that the densities declined up to 4 months post spraying and thereafter increased. Conclusions Considering the efficacy duration of DL against IRS with deltamethrin 5% WP on mosquito densities decline indoors. The results of this study suggest that DL is more effective in malaria control as its efficacy lasted more than that of IRS.
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Affiliation(s)
- Eliningaya J Kweka
- Division of Livestock and Human Diseases Mosquitoes Control, Mosquito Section, Tropical Pesticides Research Institute, P.O. Box 30214, Arusha, Tanzania. .,Department of Medical Parasitology and Entomology, Catholic University of Health and Allied Sciences, P.O. Box 1464, Mwanza, Tanzania.
| | - Ming-Chieh Lee
- Program in Public Health, College of Health Sciences, University of California Irvine, Irvine, CA, USA
| | - Beda J Mwang'onde
- Division of Livestock and Human Diseases Mosquitoes Control, Mosquito Section, Tropical Pesticides Research Institute, P.O. Box 30214, Arusha, Tanzania
| | - Filemoni Tenu
- Amani Medical Research Centre, National Institute for Medical Research, P.O. Box 81, Muheza, Tanzania
| | - Stephen Munga
- Centre for Global Health Research, Kenya Medical Research Institute, P.O.Box 1578, Kisumu, Kenya
| | - Epiphania E Kimaro
- Division of Livestock and Human Diseases Mosquitoes Control, Mosquito Section, Tropical Pesticides Research Institute, P.O. Box 30214, Arusha, Tanzania
| | - Yousif E Himeidan
- Africa Technical Research Centre, Mosquitoes Health International, P.O. Box 15500, Arusha, Tanzania
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15
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Zhao J, Yao R, Wei Y, Huang S, Keyhani NO, Huang Z. Screening of Metarhizium anisopliae UV-induced mutants for faster growth yields a hyper-virulent isolate with greater UV and thermal tolerances. Appl Microbiol Biotechnol 2016; 100:9217-9228. [DOI: 10.1007/s00253-016-7746-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/07/2016] [Accepted: 07/19/2016] [Indexed: 01/09/2023]
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16
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Zhou Y, Keyhani NO, Zhang Y, Luo Z, Fan Y, Li Y, Zhou Q, Chen J, Pei Y. Dissection of the contributions of cyclophilin genes to development and virulence in a fungal insect pathogen. Environ Microbiol 2016; 18:3812-3826. [PMID: 27130487 DOI: 10.1111/1462-2920.13339] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cyclophilins are ubiquitous proteins found in all domains of life, catalyzing peptidyl-prolyl cis-trans isomerization (PPIase activity) and functioning in diverse cellular processes. The filamentous insect pathogenic fungus, Beauveria bassiana, contains 11 cyclophilin genes whose roles were probed via individual gene knockouts, construction of over-expression strains, and a simultaneous gene knockdown strategy using tandem SiRNA. Mutants were examined for effects on conidiation, hyphal growth, cyclosporine and stress resistance, and insect virulence. BbCypA was found to be the most highly expressed cyclophilin during growth and purified recombinant BbCypA displayed cyclosporine sensitive PPIase activity. Except for ΔBbCypA, targeted gene knockouts or overexpression of any cyclophilin resulted in temperature sensitivity (TS). Specific cyclophilin mutants showed impaired hyphal growth and differential effects on conidiation and cyclosporine resistance. Insect bioassays revealed decreased virulence for two cyclophilins (ΔBbCypE and ΔBbCyp6) and the simultaneous gene knockdown mutant constructs (SiRNA30). The BbSiRNA30 strains were unaffected in growth, conidiation, or under osmotic or cell wall perturbing stress, but did show increased resistance to cyclosporine and a TS phenotype. These results revealed common and unique roles for cyclophilins in B. bassiana and validate a method for examining the effects of multi-gene families via simultaneous gene knockdown.
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Affiliation(s)
- Yonghong Zhou
- Biotechnology Research Center, Southwest University, Beibei, Chongqing, 400716, People's Republic of China.,Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, 32611, USA
| | - Nemat O Keyhani
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, 32611, USA
| | - Yongjun Zhang
- Biotechnology Research Center, Southwest University, Beibei, Chongqing, 400716, People's Republic of China
| | - Zhibing Luo
- Biotechnology Research Center, Southwest University, Beibei, Chongqing, 400716, People's Republic of China
| | - Yanhua Fan
- Biotechnology Research Center, Southwest University, Beibei, Chongqing, 400716, People's Republic of China
| | - Yujie Li
- Biotechnology Research Center, Southwest University, Beibei, Chongqing, 400716, People's Republic of China
| | - Qiaosheng Zhou
- Biotechnology Research Center, Southwest University, Beibei, Chongqing, 400716, People's Republic of China
| | - Jianjun Chen
- Biotechnology Research Center, Southwest University, Beibei, Chongqing, 400716, People's Republic of China
| | - Yan Pei
- Biotechnology Research Center, Southwest University, Beibei, Chongqing, 400716, People's Republic of China
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17
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Zhao H, Lovett B, Fang W. Genetically Engineering Entomopathogenic Fungi. ADVANCES IN GENETICS 2016; 94:137-63. [PMID: 27131325 DOI: 10.1016/bs.adgen.2015.11.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Entomopathogenic fungi have been developed as environmentally friendly alternatives to chemical insecticides in biocontrol programs for agricultural pests and vectors of disease. However, mycoinsecticides currently have a small market share due to low virulence and inconsistencies in their performance. Genetic engineering has made it possible to significantly improve the virulence of fungi and their tolerance to adverse conditions. Virulence enhancement has been achieved by engineering fungi to express insect proteins and insecticidal proteins/peptides from insect predators and other insect pathogens, or by overexpressing the pathogen's own genes. Importantly, protein engineering can be used to mix and match functional domains from diverse genes sourced from entomopathogenic fungi and other organisms, producing insecticidal proteins with novel characteristics. Fungal tolerance to abiotic stresses, especially UV radiation, has been greatly improved by introducing into entomopathogens a photoreactivation system from an archaean and pigment synthesis pathways from nonentomopathogenic fungi. Conversely, gene knockout strategies have produced strains with reduced ecological fitness as recipients for genetic engineering to improve virulence; the resulting strains are hypervirulent, but will not persist in the environment. Coupled with their natural insect specificity, safety concerns can also be mitigated by using safe effector proteins with selection marker genes removed after transformation. With the increasing public concern over the continued use of synthetic chemical insecticides and growing public acceptance of genetically modified organisms, new types of biological insecticides produced by genetic engineering offer a range of environmentally friendly options for cost-effective control of insect pests.
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Affiliation(s)
- H Zhao
- Zhejiang University, Hangzhou, Zhejiang, China
| | - B Lovett
- University of Maryland, College Park, MD, United States
| | - W Fang
- Zhejiang University, Hangzhou, Zhejiang, China
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18
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Tenebrionid secretions and a fungal benzoquinone oxidoreductase form competing components of an arms race between a host and pathogen. Proc Natl Acad Sci U S A 2015; 112:E3651-60. [PMID: 26056261 DOI: 10.1073/pnas.1504552112] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Entomopathogenic fungi and their insect hosts represent a model system for examining invertebrate-pathogen coevolutionary selection processes. Here we report the characterization of competing components of an arms race consisting of insect protective antimicrobial compounds and evolving fungal mechanisms of detoxification. The insect pathogenic fungus Beauveria bassiana has a remarkably wide host range; however, some insects are resistant to fungal infection. Among resistant insects is the tenebrionid beetle Tribolium castaneum that produces benzoquinone-containing defensive secretions. Reduced fungal germination and growth was seen in media containing T. castaneum dichloromethane extracts or synthetic benzoquinone. In response to benzoquinone exposure, the fungus expresses a 1,4-benzoquinone oxidoreductase, BbbqrA, induced >40-fold. Gene knockout mutants (ΔBbbqrA) showed increased growth inhibition, whereas B. bassiana overexpressing BbbqrA (Bb::BbbqrA(O)) displayed increased resistance to benzoquinone compared with wild type. Increased benzoquinone reductase activity was detected in wild-type cells exposed to benzoquinone and in the overexpression strain. Heterologous expression and purification of BbBqrA in Escherichia coli confirmed NAD(P)H-dependent benzoquinone reductase activity. The ΔBbbqrA strain showed decreased virulence toward T. castaneum, whereas overexpression of BbbqrA increased mortality versus T. castaneum. No change in virulence was seen for the ΔBbbqrA or Bb::BbbqrA(O) strains when tested against the greater wax moth Galleria mellonella or the beetle Sitophilus oryzae, neither of which produce significant amounts of cuticular quinones. The observation that artificial overexpression of BbbqrA results in increased virulence only toward quinone-secreting insects implies the lack of strong selection or current failure of B. bassiana to counteradapt to this particular host defense throughout evolution.
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Singh G, Prakash S. Virulency of Verticillium sp. against mosquito vectors for malaria, filarial, and dengue. ASIAN PACIFIC JOURNAL OF TROPICAL DISEASE 2015. [DOI: 10.1016/s2222-1808(15)60850-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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20
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Ortiz-Urquiza A, Luo Z, Keyhani NO. Improving mycoinsecticides for insect biological control. Appl Microbiol Biotechnol 2014; 99:1057-68. [DOI: 10.1007/s00253-014-6270-x] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 11/24/2014] [Accepted: 11/25/2014] [Indexed: 01/03/2023]
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21
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Vogels CBF, Bukhari T, Koenraadt CJM. Fitness consequences of larval exposure to Beauveria bassiana on adults of the malaria vector Anopheles stephensi. J Invertebr Pathol 2014; 119:19-24. [PMID: 24694552 DOI: 10.1016/j.jip.2014.03.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 02/23/2014] [Accepted: 03/18/2014] [Indexed: 11/25/2022]
Abstract
Entomopathogenic fungi have shown to be effective in biological control of both larval and adult stages of malaria mosquitoes. However, a small fraction of mosquitoes is still able to emerge after treatment with fungus during the larval stage. It remains unclear whether fitness of these adults is affected by the treatment during the larval stage and whether they are still susceptible for another treatment during the adult stage. Therefore, we tested the effects of larval exposure to the entomopathogenic fungus Beauveria bassiana on fitness of surviving Anopheles stephensi females. Furthermore, we tested whether larval exposed females were still susceptible to re-exposure to the fungus during the adult stage. Sex ratio, survival and reproductive success were compared between non-exposed and larval exposed A. stephensi. Comparisons were also made between survival of non-exposed and larval exposed females that were re-exposed to B. bassiana during the adult stage. Larval treatment did not affect sex ratio of emerging mosquitoes. Larval exposed females that were infected died significantly faster and laid equal numbers of eggs from which equal numbers of larvae hatched, compared to non-exposed females. Larval exposed females that were uninfected had equal survival, but laid a significantly larger number of eggs from which a significantly higher number of larvae hatched, compared to non-exposed females. Larval exposed females which were re-exposed to B. bassiana during the adult stage had equal survival as females exposed only during the adult stage. Our results suggest that individual consequences for fitness of larval exposed females depended on whether a fungal infection was acquired during the larval stage. Larval exposed females remained susceptible to re-exposure with B. bassiana during the adult stage, indicating that larval and adult control of malaria mosquitoes with EF are compatible.
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Affiliation(s)
- Chantal B F Vogels
- Laboratory of Entomology, Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands.
| | - Tullu Bukhari
- Laboratory of Entomology, Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands; Unit of Insect Vector Genetics and Genomics, Institute Pasteur, 25-28, Rue du Docteur Roux, 75724 Paris, France.
| | - Constantianus J M Koenraadt
- Laboratory of Entomology, Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands.
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22
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Ying SH, Feng MG, Keyhani NO. A carbon responsive G-protein coupled receptor modulates broad developmental and genetic networks in the entomopathogenic fungus,Beauveria bassiana. Environ Microbiol 2013; 15:2902-21. [DOI: 10.1111/1462-2920.12169] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 05/23/2013] [Accepted: 05/25/2013] [Indexed: 11/27/2022]
Affiliation(s)
| | - Ming-Guang Feng
- Institute of Microbiology; College of Life Sciences; Zhejiang University; Hangzhou; 310058; China
| | - Nemat O. Keyhani
- Department of Microbiology and Cell Science; University of Florida; Gainesville; FL; 32611; USA
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