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Xiao Z, Yao X, Bai S, Wei J, An S. Involvement of an Enhanced Immunity Mechanism in the Resistance to Bacillus thuringiensis in Lepidopteran Pests. INSECTS 2023; 14:151. [PMID: 36835720 PMCID: PMC9965922 DOI: 10.3390/insects14020151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 01/21/2023] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
Bacillus thuringiensis (Bt) is the safest, economically successful entomopathogen to date. It is extensively produced in transgenic crops or used in spray formulations to control Lepidopteran pests. The most serious threat to the sustainable usage of Bt is insect resistance. The resistance mechanisms to Bt toxins depend not only on alterations in insect receptors, but also on the enhancement of insect immune responses. In this work, we review the current knowledge of the immune response and resistance of insects to Bt formulations and Bt proteins, mainly in Lepidopteran pests. We discuss the pattern recognition proteins for recognizing Bt, antimicrobial peptides (AMPs) and their synthetic signaling pathways, the prophenoloxidase system, reactive oxygen species (ROS) generation, nodulation, encapsulation, phagocytosis, and cell-free aggregates, which are involved in immune response reactions or resistance to Bt. This review also analyzes immune priming, which contributes to the evolution of insect resistance to Bt, and puts forward strategies to improve the insecticidal activity of Bt formulations and manage insect resistance, targeting the insect immune responses and resistance.
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Dutta TK, Santhoshkumar K, Veeresh A, Waghmare C, Mathur C, Sreevathsa R. RNAi-based knockdown of candidate gut receptor genes altered the susceptibility of Spodoptera frugiperda and S. litura larvae to a chimeric toxin Cry1AcF. PeerJ 2023; 11:e14716. [PMID: 36710863 PMCID: PMC9881468 DOI: 10.7717/peerj.14716] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 12/19/2022] [Indexed: 01/25/2023] Open
Abstract
Background A multitude of Cry toxins (secreted by Bacillus thuringiensis or Bt) has been deployed globally either via transgenic mean or bio-pesticidal formulations in order to manage insect pests. However, Bt resistance development in insects is emerging as a major concern. To avoid this problem, multiple gene pyramiding or protein-engineered chimeric toxin-based strategy has been analyzed. Methods In the present study, one such chimeric toxin Cry1AcF (contain the swapped domains of Cry1Ac and Cry1F) was used to investigate its in vivo pathogenesis process in lepidopteran pests Spodoptera frugiperda and S. litura. A number of biochemical and molecular analysis were performed. Results Oral ingestion of Cry1AcF caused greater toxicity in S. frugiperda than S. litura with larvae displaying increased hemolymph melanization. Histopathology of the midgut transverse sections exhibited Cry1AcF-induced extensive gut damage in both the test insects followed by cytotoxicity in terms of reduced hemocyte numbers and viability. Elevated hemolymph phenoloxidase activity indicated the immune-stimulatory nature of Cry1AcF. In order to analyze the role of gut receptor proteins in Cry1AcF intoxication in test insects, we performed RNAi-mediated silencing using bacterially-expressed dsRNAs of individual receptor-encoding genes including CAD, ABCC2, ALP1 and APN. Target-specific induced downregulation of receptor mRNAs differentially altered the insect susceptibility to Cry1AcF toxin in our study. The susceptibility of ALP1 and APN dsRNA pre-treated S. frugiperda was considerably decreased when treated with Cry1AcF in LD50 and LD90 doses, whereas susceptibility of CAD and ABCC2 dsRNA pre-treated S. litura was significantly reduced when ingested with Cry1AcF in different doses. CAD/ABCC2-silenced S. frugiperda and ALP1/APN-silenced S. litura were vulnerable to Cry1AcF alike of control larvae. In conclusion, our results indicate ALP1/APN and CAD/ABCC2 as the functional receptor for Cry1AcF toxicity in S. frugiperda and S. litura, respectively.
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Affiliation(s)
- Tushar K. Dutta
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, Delhi, India
| | | | - Arudhimath Veeresh
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, Delhi, India
| | - Chandramani Waghmare
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, Delhi, India
| | - Chetna Mathur
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, Delhi, India
| | - Rohini Sreevathsa
- ICAR-National Institute for Plant Biotechnology, New Delhi, Delhi, India
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Quicke DLJ, Butcher BA. Review of Venoms of Non-Polydnavirus Carrying Ichneumonoid Wasps. BIOLOGY 2021; 10:50. [PMID: 33445639 PMCID: PMC7828074 DOI: 10.3390/biology10010050] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 12/23/2022]
Abstract
Parasitoids are predominantly insects that develop as larvae on or inside their host, also usually another insect, ultimately killing it after various periods of parasitism when both parasitoid larva and host are alive. The very large wasp superfamily Ichneumonoidea is composed of parasitoids of other insects and comprises a minimum of 100,000 species. The superfamily is dominated by two similarly sized families, Braconidae and Ichneumonidae, which are collectively divided into approximately 80 subfamilies. Of these, six have been shown to release DNA-containing virus-like particles, encoded within the wasp genome, classified in the virus family Polydnaviridae. Polydnaviruses infect and have profound effects on host physiology in conjunction with various venom and ovarial secretions, and have attracted an immense amount of research interest. Physiological interactions between the remaining ichneumonoids and their hosts result from adult venom gland secretions and in some cases, ovarian or larval secretions. Here we review the literature on the relatively few studies on the effects and chemistry of these ichneumonoid venoms and make suggestions for interesting future research areas. In particular, we highlight relatively or potentially easily culturable systems with features largely lacking in currently studied systems and whose study may lead to new insights into the roles of venom chemistry in host-parasitoid relationships as well as their evolution.
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Affiliation(s)
- Donald L. J. Quicke
- Integrative Ecology Laboratory, Department of Biology, Faculty of Science, Chulalongkorn University, Phayathai Road, Pathumwan 10330, Thailand;
- Center of Excellence in Entomology, Bee Biology, Diversity of Insects and Mites, Chulalongkorn University, Phayathai Road, Pathumwan 10330, Thailand
| | - Buntika A. Butcher
- Integrative Ecology Laboratory, Department of Biology, Faculty of Science, Chulalongkorn University, Phayathai Road, Pathumwan 10330, Thailand;
- Center of Excellence in Entomology, Bee Biology, Diversity of Insects and Mites, Chulalongkorn University, Phayathai Road, Pathumwan 10330, Thailand
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A toxin complex protein from Photorhabdus akhurstii conferred oral insecticidal activity against Galleria mellonella by targeting the midgut epithelium. Microbiol Res 2020; 242:126642. [PMID: 33191102 DOI: 10.1016/j.micres.2020.126642] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/16/2020] [Accepted: 10/30/2020] [Indexed: 02/08/2023]
Abstract
The nematode-bacterium pair Heterorhabditis indica-Photorhabdus akhurstii is a malleable model system to investigate mutualistic relations. A number of toxins produced by P. akhurstii allow the bacterium to kill the insect host. However, a few of these heterologously expressed toxins are orally active against different insects which possibly caused neglected attention to Photorhabdus toxins compared to Bt (Bacillus thuringiensis). In the current study, a functional subunit of orally active toxin complex (Tc) protein, TcaB (63 kDa), isolated from two strains of P. akhurstii namely IARI-SGHR2 and IARI-SGMS1, was tested for biological activity against Galleria mellonella. A force feeding-based administration of the toxin translated into LD50 values of 45.63-58.90 ng/g which was even lower compared to injection LD50 values (51.48-64.30 ng/g) at 48 h after inoculation. An oral uptake of 500 ng toxin caused extensive gut damage in G. mellonella during 6-24 h incubation period coupled with a gradual disruption of gut integrity leading to escape of TcaB into the hemocoel. This finding was supported by the cytotoxic and immune-stimulatory effect of TcaB in the insect hemocoel at 6-24 h after force feeding. The circulatory hemocyte numbers and cell viability was markedly reduced to 0.66-0.68 × 106 ml-1 and 49-52 %, respectively, in TcaB force fed insect at 24 h, compared to control (2.55 × 106 ml-1; 100 %). The hemolymph phenoloxidase (PO) activity was elevated by 10.2-fold in force fed larvae than control at 24 h. An in silico docking study revealed that TcaB putatively interacts with a number of G. mellonella receptor proteins in order to become a gut-active toxin. Present research reinforces the potential of gut-active Photorhabdus toxins for their inclusion in sustainable insect management tactics and strengthens the existing Bt-dominated management repository.
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Zhao W, Shi M, Ye XQ, Li F, Wang XW, Chen XX. Comparative transcriptome analysis of venom glands from Cotesia vestalis and Diadromus collaris, two endoparasitoids of the host Plutella xylostella. Sci Rep 2017; 7:1298. [PMID: 28465546 PMCID: PMC5431001 DOI: 10.1038/s41598-017-01383-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 03/29/2017] [Indexed: 11/09/2022] Open
Abstract
Venoms secreted by the venom gland (VG) of parasitoid wasp help ensure successful parasitism by host immune suppression and developmental regulation. Cotesia vestalis, a larval endoparasitoid, and Diadromus collaris, a pupal endoparasitoid, parasitize the diamondback moth (DBM), Plutella xylostella. To explore and compare the venom components of two endoparasitoids, we sequenced transcriptomes of the VGs and wasp bodies without VGs (BWVGs) of the two endoparasitoids. Statistically enriched GO terms and KEGG pathways of the two VGs compared to respective whole-body background were similar and reflected active protein biosynthesis activities in the two VGs. 1,595 VG specific genes of the D. collaris VG and 1,461 VG specific genes of the C. vestalis VG were identified by comparative transcript profiling. A total of 444 and 513 genes encoding potential secretory proteins were identified and defined as putative venom genes in D. collaris VG and C. vestalis VG, respectively. The putative venom genes of the two wasps showed no significant similarity or convergence. More venom genes were predicted in D. collaris VG than C. vestalis VG, especially hydrolase-coding genes. Differences in the types and quantities of putative venom genes shed light on different venom functions.
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Affiliation(s)
- Wei Zhao
- Institute of Insect Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Min Shi
- Institute of Insect Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Xi-Qian Ye
- Institute of Insect Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Fei Li
- Institute of Insect Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Xiao-Wei Wang
- Institute of Insect Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China
| | - Xue-Xin Chen
- Institute of Insect Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China.
- Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China.
- State Key Lab of Rice Biology, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, China.
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Richards EH, Dani MP, Lu Y, Butt T, Weaver RJ. Effect of stress on heat shock protein levels, immune response and survival to fungal infection of Mamestra brassicae larvae. JOURNAL OF INSECT PHYSIOLOGY 2017; 96:53-63. [PMID: 27789295 DOI: 10.1016/j.jinsphys.2016.10.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 10/20/2016] [Accepted: 10/20/2016] [Indexed: 06/06/2023]
Abstract
Although the utilisation of fungal biological control agents to kill insect pests is desirable, it is known that the outcome of infection may be influenced by a number of criteria, including whether or not the target insect is stressed. In the current work, topical treatment of larvae of the lepidopteran pest, Mamestra brassicae, with conidia of Beauveria bassiana, followed by a heat stress (HS; 37°C for 1h) 48h later, resulted in a similar level of larval survival to that occurring for no heat stress (No-HS), fungus-treated larvae. By contrast, when the HS was applied 24h after fungal treatment, larval survival was significantly increased, indicating that the HS is protecting the larvae from B. bassiana. Similarly, exposure of larvae to a HS provided protection against Metarhizium brunneum (V275) at 48h (but not 24h) after fungal treatment. To elucidate the mechanism(s) that might contribute to HS-induced increases in larval survival against fungal infection, the effects of a HS on key cellular and humoral immune responses and on the level of selected heat shock proteins (HSP) were assessed. When larvae were kept under control (No HS) conditions, there was no significant difference in the haemocyte number per ml of haemolymph over a 24h period. However, exposure of larvae to a HS, significantly increased the haemocyte density immediately after (t=0h) and 4h after HS compared to the No HS controls, whilst it returned to control levels at t=24h. In addition, in vitro assays indicated that haemocytes harvested from larvae immediately after (0h) and 4h (but not 24h) after a HS exhibited higher rates of phagocytosis of FITC-labelled B. bassiana conidia compared to haemocytes harvested from non-HS larvae. Interestingly, the HS did not appear to increase anti-fungal activity in larval plasma. Western blot analysis using antibodies which cross react with Drosophila melanogaster HSP, resulted in a relatively strong signal for HSP 70 and HSP 90 from extracts of 50,000 and 100,000haemocytes, respectively, harvested from No-HS larvae. By contrast, for HSP 60, a lysate derived from 200,000haemocytes resulted in a relatively weak signal. When larvae were exposed to a HS, the level of all three HSP increased compared to the No HS control 4h and 16h after the HS. However, 24h after treatment, any heat stress-mediated increase in HSP levels was minimal and not consistently detected. Similar results were obtained when HSP 90, 70, and 60 levels were assessed in fat body harvested from heat stressed and non-heat stressed larvae. With regard to HSP 27, no signal was obtained even when a lysate from 200,000haemocytes or three times the amount of fat body were processed, suggesting that the anti-HSP 27 antibody utilised does not cross-react with the M. brassicae HSP. The results suggest that a HS-mediated increase in haemocyte density and phagocytic activity, together with an upregulation of HSP 90 and 70, may contribute to increasing the survival of M. brassicae larvae treated with B. bassiana and M. brunneum (V275).
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Affiliation(s)
| | - M P Dani
- Fera, Sand Hutton, York YO41 1LZ, UK
| | - Y Lu
- Fera, Sand Hutton, York YO41 1LZ, UK
| | - T Butt
- Department of Biosciences, College of Science, Swansea University, Singleton Park, Swansea SA2 8PP, UK
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Midgut microbiota and host immunocompetence underlie Bacillus thuringiensis killing mechanism. Proc Natl Acad Sci U S A 2016; 113:9486-91. [PMID: 27506800 DOI: 10.1073/pnas.1521741113] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacillus thuringiensis is a widely used bacterial entomopathogen producing insecticidal toxins, some of which are expressed in insect-resistant transgenic crops. Surprisingly, the killing mechanism of B. thuringiensis remains controversial. In particular, the importance of the septicemia induced by the host midgut microbiota is still debated as a result of the lack of experimental evidence obtained without drastic manipulation of the midgut and its content. Here this key issue is addressed by RNAi-mediated silencing of an immune gene in a lepidopteran host Spodoptera littoralis, leaving the midgut microbiota unaltered. The resulting cellular immunosuppression was characterized by a reduced nodulation response, which was associated with a significant enhancement of host larvae mortality triggered by B. thuringiensis and a Cry toxin. This was determined by an uncontrolled proliferation of midgut bacteria, after entering the body cavity through toxin-induced epithelial lesions. Consequently, the hemolymphatic microbiota dramatically changed upon treatment with Cry1Ca toxin, showing a remarkable predominance of Serratia and Clostridium species, which switched from asymptomatic gut symbionts to hemocoelic pathogens. These experimental results demonstrate the important contribution of host enteric flora in B. thuringiensis-killing activity and provide a sound foundation for developing new insect control strategies aimed at enhancing the impact of biocontrol agents by reducing the immunocompetence of the host.
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Dubovskiy IM, Grizanova EV, Whitten MMA, Mukherjee K, Greig C, Alikina T, Kabilov M, Vilcinskas A, Glupov VV, Butt TM. Immuno-physiological adaptations confer wax moth Galleria mellonella resistance to Bacillus thuringiensis. Virulence 2016; 7:860-870. [PMID: 27029421 PMCID: PMC5160394 DOI: 10.1080/21505594.2016.1164367] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
Microevolutionary mechanisms of resistance to a bacterial pathogen were explored in a population of the Greater wax moth, Galleria mellonella, selected for an 8.8-fold increased resistance against the entomopathogenic bacterium Bacillus thuringiensis (Bt) compared with a non-selected (suspectible) line. Defense strategies of the resistant and susceptible insect lines were compared to uncover mechanisms underpinning resistance, and the possible cost of those survival strategies. In the uninfected state, resistant insects exhibited enhanced basal expression of genes related to regeneration and amelioration of Bt toxin activity in the midgut. In addition, these insects also exhibited elevated activity of genes linked to inflammation/stress management and immune defense in the fat body. Following oral infection with Bt, the expression of these genes was further elevated in the fat body and midgut of both lines and to a greater extent some of them in resistant line than the susceptible line. This gene expression analysis reveals a pattern of resistance mechanisms targeted to sites damaged by Bt with the insect placing greater emphasis on tissue repair as revealed by elevated expression of these genes in both the fat body and midgut epithelium. Unlike the susceptible insects, Bt infection significantly reduced the diversity and richness (abundance) of the gut microbiota in the resistant insects. These observations suggest that the resistant line not only has a more intact midgut but is secreting antimicrobial factors into the gut lumen which not only mitigate Bt activity but also affects the viability of other gut bacteria. Remarkably the resistant line employs multifactorial adaptations for resistance to Bt without any detected negative trade off since the insects exhibited higher fecundity.
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Affiliation(s)
- Ivan M Dubovskiy
- a Institute of Systematics and Ecology of Animals, Siberian Branch of Russian Academy of Science , Novosibirsk , Russia
| | - Ekaterina V Grizanova
- a Institute of Systematics and Ecology of Animals, Siberian Branch of Russian Academy of Science , Novosibirsk , Russia
| | - Miranda M A Whitten
- b Institute of Life Science, College of Medicine, Swansea University , Swansea , Wales , UK
| | - Krishnendu Mukherjee
- c Department of Bioresources , Fraunhofer Institute for Molecular Biology and Applied Ecology , Giessen , Germany
| | - Carolyn Greig
- d Department of Biosciences , College of Science, Swansea University , Swansea , Wales , UK
| | - Tatiana Alikina
- e Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Science , Novosibirsk , Russia
| | - Marsel Kabilov
- e Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Science , Novosibirsk , Russia
| | - Andreas Vilcinskas
- f Institute for Insect Biotechnology, Justus-Liebig University , Giessen , Germany
| | - Viktor V Glupov
- a Institute of Systematics and Ecology of Animals, Siberian Branch of Russian Academy of Science , Novosibirsk , Russia
| | - Tariq M Butt
- d Department of Biosciences , College of Science, Swansea University , Swansea , Wales , UK
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Richards EH, Wontner-Smith T, Bradish H, Dani MP, Cotterill JV. Novel control methods for insect pests: development of a microencapsulation procedure for proteinaceous bioactives intended for oral delivery. PEST MANAGEMENT SCIENCE 2015; 71:1238-1246. [PMID: 25233850 DOI: 10.1002/ps.3912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 08/15/2014] [Accepted: 09/15/2014] [Indexed: 06/03/2023]
Abstract
BACKGROUND The objective was to develop an environmentally favourable microcapsule suitable for delivery of proteinaceous bioactive agents ('bioinsecticides') to pest insects. RESULTS Utilising feeding bioassays, we determined that microspheres made of alginate can be produced in a variety of sizes and are palatable and non-toxic to larvae of the lepidopteran pest Lacanobia oleracea. Dehydrated microspheres were also readily ingested by larvae. Using a novel feeding bioassay and alginate microspheres containing a fluorescent marker material (coumarin 7 encapsulated in styrene maleic anhydride beads), we determined that the microspheres successfully deliver the marker to the insect gut. Moreover, the alginate microspheres rapidly break down in the alkaline conditions of the insect gut and release their contents, the beads passing through the gut in 2-3 h. Using bovine serum albumin as a test protein and western blotting, it was determined that alginate can successfully encapsulate protein, and that the microspheres can be stored in a CaCl2 solution for up to 24 days without extensive leakage. Importantly, it was also determined that alginate and the microsphere-making procedure developed do not inactivate rVPr1 (an insect immunosuppressive protein and potential bioinsecticide). CONCLUSIONS An alginate-based microsphere has potential to deliver the proteinaceous bioactive rVPr1 to pest insects.
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Affiliation(s)
- Elaine H Richards
- Plant Protection Programme, Food and Environment Research Agency, Sand Hutton, York, UK
| | - Tim Wontner-Smith
- Food Quality and Safety Programme, Food and Environment Research Agency, Sand Hutton, York, UK
| | - Hannah Bradish
- Plant Protection Programme, Food and Environment Research Agency, Sand Hutton, York, UK
| | - M Paulina Dani
- Plant Protection Programme, Food and Environment Research Agency, Sand Hutton, York, UK
| | - Jane V Cotterill
- Food Quality and Safety Programme, Food and Environment Research Agency, Sand Hutton, York, UK
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Grizanova EV, Dubovskiy IM, Whitten MMA, Glupov VV. Contributions of cellular and humoral immunity of Galleria mellonella larvae in defence against oral infection by Bacillus thuringiensis. J Invertebr Pathol 2014; 119:40-6. [PMID: 24735783 DOI: 10.1016/j.jip.2014.04.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Revised: 04/02/2014] [Accepted: 04/04/2014] [Indexed: 01/12/2023]
Abstract
In this study the cellular and humoral immune reactions of the Greater wax moth Galleria mellonella have been investigated during bacterial infection caused by oral administration of Bacillus thuringiensis. Two different dose strengths were investigated to assess the contribution of immune parameters to induced Bt resistance. Low-dose (sublethal LC15) infection resulted in significantly elevated haemolymph phenoloxidase and lysozyme-like activity, enhanced phagocytic activity of haemocytes, and increased encapsulation responses in infected larvae at 48 and 72 h post infection. Higher doses of Bt (half-lethal LC50) also triggered significantly elevated haemolymph phenoloxidase and lysozyme-like activity, but decreased the coagulation index and activity of phenoloxidase in haemocytes of infected larvae. In both types of infection, the pool of circulating haemocytes became depleted. The importance of cellular and humoral immune reactions in induced insect resistance to intestinal bacterial infection Bt is herein discussed.
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Affiliation(s)
- E V Grizanova
- Institute of Systematics and Ecology of Animals, Siberian Branch of Russian Academy of Science, Frunze Street 11, 630091 Novosibirsk, Russia
| | - I M Dubovskiy
- Institute of Systematics and Ecology of Animals, Siberian Branch of Russian Academy of Science, Frunze Street 11, 630091 Novosibirsk, Russia.
| | - M M A Whitten
- Institute of Life Science, College of Medicine, Swansea University, Singleton Park, Swansea SA2 8PP, UK
| | - V V Glupov
- Institute of Systematics and Ecology of Animals, Siberian Branch of Russian Academy of Science, Frunze Street 11, 630091 Novosibirsk, Russia
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Beck B, Brusselman E, Nuyttens D, Moens M, Temmerman F, Pollet S, Van Weyenberg S, Spanoghe P. Improving the biocontrol potential of entomopathogenic nematodes against Mamestra brassicae: effect of spray application technique, adjuvants and an attractant. PEST MANAGEMENT SCIENCE 2014; 70:103-112. [PMID: 23512412 DOI: 10.1002/ps.3533] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 01/08/2013] [Accepted: 03/19/2013] [Indexed: 06/01/2023]
Abstract
BACKGROUND Steinernema carpocapsae Weiser, an entomopathogenic nematode (EPN), is a potential biological control agent for the cabbage moth (Mamestra brassicae L.). This research aimed to identify a suitable spray application technique, and to determine whether yeast extract added to an EPN spray has an attracting and/or a feeding stimulant effect on M. brassicae. The biological control capabilities of EPN against this pest were examined in the field. RESULTS Good coverage of the underside of cauliflower leaves, the habitat of young instar larvae (L1-L4) of M. brassicae was obtained using different spray boom configurations with vertical extensions that carried underleaf spraying nozzles. One of the configurations was selected for field testing with an EPN spray. Brewer's yeast extract stimulated larval feeding on leaves, and increased the mortality of these larvae when exposed to EPN. The field trial showed that a spray application with S. carpocapsae, Addit and xanthan gum can effectively lower the numbers of cabbage heads damaged by M. brassicae. Brewer's yeast extract did not significantly increase this field performance of EPN. CONCLUSION Steinernema carpocapsae, applied with an appropriate spray technique, can be used within biological control schemes as part of a resistance management programme for Bt.
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Affiliation(s)
- Bert Beck
- Institute for Agricultural and Fisheries Research (ILVO), Technology and Food Science Unit, Agricultural Engineering, Merelbeke, Belgium
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Richards EH, Dani MP, Bradish H. Immunosuppressive properties of a protein (rVPr1) from the venom of the endoparasitic wasp, Pimpla hypochondriaca: Mechanism of action and potential use for improving biological control strategies. JOURNAL OF INSECT PHYSIOLOGY 2013; 59:213-222. [PMID: 22698823 DOI: 10.1016/j.jinsphys.2012.06.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 05/15/2012] [Accepted: 06/01/2012] [Indexed: 06/01/2023]
Abstract
Previously, it was determined that the presence of rVPr1 (a recombinant Pimpla hypochondriaca venom protein), in the haemocoel of two lepidopteran larvae, significantly increases their susceptibility to the biological control agents (BCAs), Bacillus thuringiensis (Bt) and Beauveria bassiana (Richards and Dani, 2010; Richards et al., 2011). The current work examines the mechanism of action of rVPr1 and demonstrates that it binds to the surface of some haemocytes and disrupts the organization of the haemocyte cytoskeleton. This binding is associated with a reduction in the ability of haemocytes to extend pseudopods, and to move and form aggregates in vitro over an 18 h period. Moreover, rVPr1 exerts these effects after a relatively short incubation period (1.5 h) and the haemocytes do not recover their ability to form aggregates after rVPr1 has been removed. In addition, rVPr1 significantly reduces haemocyte-mediated phagocytosis of Bt and B. bassiana in vitro (p < 0.05) and, following injection into the insect haemocoel, rVPr1 reduces the number of circulating haemocytes per ml of haemolymph (this being significantly different to the controls 3 h after injection [p = 0.05]). The finding that rVPr1 has an adverse effect on haemocyte function and number in vivo, supports the hypothesis that this wasp protein significantly increases the susceptibility of lepidopteran larvae to Bt and B. bassiana, by suppressing haemocyte-mediated immune responses in the insects which otherwise would be directed against these BCAs.
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Affiliation(s)
- E H Richards
- Food and Environment Research Agency, Sand Hutton, York YO41 1LZ, United Kingdom.
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Richards EH, Bradish H, Dani MP, Pietravalle S, Lawson A. Recombinant immunosuppressive protein from Pimpla hypochondrica venom (rVPr1) increases the susceptibility of Mamestra brassicae larvae to the fungal biological control agent, Beauveria bassiana. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2011; 78:119-131. [PMID: 21948634 DOI: 10.1002/arch.20447] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Although fungi are used to control a variety of insect pests, it is accepted that their usage could be increased if their efficacy was greater. The outcome of the interaction of a fungus and a pest insect may be influenced by a number of criteria, including the ability of the insect to mount effective immune responses against the pathogen. In view of this, we aimed to determine if a recombinant immunosuppressive wasp venom protein (rVPr1) can increase the susceptibility of larvae of the lepidopteran pest, Mamestra brassicae, to the fungal biological control agent, Beauveria bassiana. Bioassays indicated that when larvae were injected with 3.5 µl of rVPr1 and 100 B. bassiana conidia (combined injection assays), a significant reduction in survival of larvae occurred compared with each treatment on its own (P=0.006). Similar results were obtained when larvae were dipped in a solution containing 3 × 10(6) B. bassiana conidia per ml and then injected with 3.5 µl of rVPr1 2 days later (topical application assays), (P<0.001). These results indicate that rVPr1 can increase the efficacy of B. bassiana toward a lepidopteran pest, and are discussed within the context of insect immune responses and integrated pest management.
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Affiliation(s)
- Elaine H Richards
- The Food and Environment Research Agency, Sand Hutton, York, United Kingdom.
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Chandler D, Bailey AS, Tatchell GM, Davidson G, Greaves J, Grant WP. The development, regulation and use of biopesticides for integrated pest management. Philos Trans R Soc Lond B Biol Sci 2011; 366:1987-98. [PMID: 21624919 DOI: 10.1098/rstb.2010.0390] [Citation(s) in RCA: 232] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Over the past 50 years, crop protection has relied heavily on synthetic chemical pesticides, but their availability is now declining as a result of new legislation and the evolution of resistance in pest populations. Therefore, alternative pest management tactics are needed. Biopesticides are pest management agents based on living micro-organisms or natural products. They have proven potential for pest management and they are being used across the world. However, they are regulated by systems designed originally for chemical pesticides that have created market entry barriers by imposing burdensome costs on the biopesticide industry. There are also significant technical barriers to making biopesticides more effective. In the European Union, a greater emphasis on Integrated Pest Management (IPM) as part of agricultural policy may lead to innovations in the way that biopesticides are regulated. There are also new opportunities for developing biopesticides in IPM by combining ecological science with post-genomics technologies. The new biopesticide products that will result from this research will bring with them new regulatory and economic challenges that must be addressed through joint working between social and natural scientists, policy makers and industry.
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Affiliation(s)
- David Chandler
- School of Life Sciences, University of Warwick, Wellesbourne, Warwick CV35 9EF, UK.
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