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Hu H, Yin X, Pang S, Jiang Y, Weng Q, Hu Q, Wang J. Mechanism of destruxin a inhibits juvenile hormone binding protein transporting juvenile hormone to affect insect growth. Pestic Biochem Physiol 2023; 197:105654. [PMID: 38072529 DOI: 10.1016/j.pestbp.2023.105654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 09/22/2023] [Accepted: 10/17/2023] [Indexed: 12/18/2023]
Abstract
Destruxin A, a non-ribosomal peptide toxin produced by Metarhizium, exhibits potent insecticidal activity by targeting various tissues, organs, and cells of insects. Our previous research has revealed that DA possesses the ability to bind to multiple proteins. In this study, we aimed to identify the most sensitive binding proteins of DA and investigate the physiological processes in which DA regulated. Through RNAi technology, we screened 22 binding proteins of DA in silkworm hemolymph. Among them, the juvenile hormone binding protein (JHBP), a hormone transport protein crucial for growth and development regulation, exhibited the highest sensitivity to DA. Subsequent experiments demonstrated that DA could inhibit the body weight gain of silkworm larvae, accelerate the pupation occurrence, and modulate the content of free juvenile hormone (JH) in the hemolymph. We also observed that DA could induce conformational changes in both the JHBP and the JHBP-JH binding complex. Notably, at low dosage, DA influenced the binding of JHBP to JH, while at high dosage, it irreversibly affected the binding of JHBP to JH. Molecular docking and point-mutant experiments suggested that DA might affect the N-arm of JHBP, which is responsible for JH binding. Additionally, we discovered that JHBP is widely distributed in various tissues of the silkworm, including the epidermis, gut, fat body, Malpighian tubule, gonad, muscle, trachea, and hemocyte. This study provides novel insights into the insecticidal mechanism of DA and enhances our understanding of the pathogenic process of Metarhizium.
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Affiliation(s)
- Hongwang Hu
- College of Plant Protection, South China Agricultural University, Guangzhou 510642, China.
| | - Xuyu Yin
- College of Plant Protection, South China Agricultural University, Guangzhou 510642, China.
| | - Suyun Pang
- College of Plant Protection, South China Agricultural University, Guangzhou 510642, China.
| | - Yali Jiang
- College of Plant Protection, South China Agricultural University, Guangzhou 510642, China.
| | - Qunfang Weng
- College of Plant Protection, South China Agricultural University, Guangzhou 510642, China.
| | - Qiongbo Hu
- College of Plant Protection, South China Agricultural University, Guangzhou 510642, China.
| | - Jingjing Wang
- College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; College of Horticulture, South China Agricultural University, Guangzhou 510642, China.
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Tomilova OG, Kryukov VY, Kryukova NA, Tolokonnikova KP, Tokarev YS, Rumiantseva AS, Alekseev AA, Glupov VV. Effects of passages through an insect or a plant on virulence and physiological properties of the fungus Metarhizium robertsii. PeerJ 2023; 11:e15726. [PMID: 37583910 PMCID: PMC10424674 DOI: 10.7717/peerj.15726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 06/18/2023] [Indexed: 08/17/2023] Open
Abstract
Species of the genus Metarhizium are characterized by a multitrophic lifestyle of being arthropod parasites, rhizosphere colonizers, endophytes, and saprophytes. The process of adaptation to various organisms and substrates may lead to specific physiological alterations that can be elucidated by passaging through different hosts. Changes in virulence and cultivation properties of entomopathogenic fungi subcultured on different media or passaged through a live insect host are well known. Nevertheless, comparative in-depth physiological studies on fungi after passaging through insect or plant organisms are scarce. Here, virulence, plant colonization, hydrolytic enzymatic activities, toxin production, and antimicrobial action were compared between stable (nondegenerative) parent strain Metarhizium robertsii MB-1 and its reisolates obtained after eight passages through Galleria mellonella larvae or Solanum lycopersicum or after subculturing on the Sabouraud medium. The passaging through the insect caused similar physiological alterations relative to the plant-based passaging: elevation of destruxin A, B, and E production, a decrease in protease and lipase activities, and lowering of virulence toward G. mellonella and Leptinotarsa decemlineata as compared to the parent strain. The reisolates passaged through the insect or plant showed a slight trend toward increased tomato colonization and enhanced antagonistic action on tomato-associated bacterium Bacillus pumilus as compared to the parental strain. Meanwhile, the subculturing of MB-1 on the Sabouraud medium showed stability of the studied parameters, with minimal alterations relative to the parental strain. We propose that the fungal virulence factors are reprioritized during adaptation of M. robertsii to insects, plants, and media.
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Affiliation(s)
- Oksana G. Tomilova
- Institute of Systematics and Ecology of Animals SB RAS, Novosibirsk, Russia
- All-Russian Institute of Plant Protection, St. Petersburg, Russia
| | - Vadim Y. Kryukov
- Institute of Systematics and Ecology of Animals SB RAS, Novosibirsk, Russia
| | | | | | - Yuri S. Tokarev
- All-Russian Institute of Plant Protection, St. Petersburg, Russia
| | | | - Alexander A. Alekseev
- Institute of Systematics and Ecology of Animals SB RAS, Novosibirsk, Russia
- Voevodsky Institute of Chemical Kinetics and Combustion SB RAS, Novosibirsk, Russia
| | - Viktor V. Glupov
- Institute of Systematics and Ecology of Animals SB RAS, Novosibirsk, Russia
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Abstract
Destruxin A (DA) is a cyclo-hexadepsipeptidic insecticidal mycotoxin isolated from the entomopathogenic fungi, Metarhizium spp. However, its mode of action is unknown. In this study, we isolated 149 candidate DA-binding proteins by drug affinity response target stability, and determined the interactions of 80 canditates with DA in vitro by surface plasmon resonance. The affinity coefficients (KD) ranged from 24 to 469 μM. Binding proteins were functionally diverse and included cytoskeletal components and cell motility, protein transcription and translation pathways, ubiquitin dependent protein metabolic processes, nucleus pore entry and exit, and endoplasmic reticulum vesicle transport and etc. Electron microscopy revealed that DA damaged the cytoskeleton and multiple organelles, disrupted cell adhesion and motility, and led to cell death. DA appeared to have a multi-targeted approach to cellular structures and multiple life processes, leading to cell death. The results of this study could provide molecular evidence for the analysis of the insecticidal toxicology of DA and further improve the study of the pathogenic insect mechanism of Metarhizium.
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Affiliation(s)
- Jingjing Wang
- National Key Laboratory of Green Pesticide; Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, College of Plant Protection, South China Agricultural University, Guangzhou, 510642, China
- College of Horticulture, South China Agricultural University, Guangzhou, 510642, China
| | - Qunfang Weng
- National Key Laboratory of Green Pesticide; Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, College of Plant Protection, South China Agricultural University, Guangzhou, 510642, China
| | - Ke Zhang
- National Key Laboratory of Green Pesticide; Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, College of Plant Protection, South China Agricultural University, Guangzhou, 510642, China
| | - Qiongbo Hu
- National Key Laboratory of Green Pesticide; Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, College of Plant Protection, South China Agricultural University, Guangzhou, 510642, China.
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Shanbhag SR, Vazhappilly AT, Sane A, D'Silva NM, Tripathi S. Electrolyte transport pathways induced in the midgut epithelium of Drosophila melanogaster larvae by commensal gut microbiota and pathogens. J Physiol 2016; 595:523-539. [PMID: 27373966 DOI: 10.1113/jp272617] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 06/20/2016] [Indexed: 02/01/2023] Open
Abstract
KEY POINTS The digestive tract of larval and adult Drosophila is an excellent analogue of the mammalian gut. Enterocytes of the posterior midgut are separated by septa, with no paracellular path, and therefore perform both immune and transport functions. Using microperfusion electrophysiology, we show that larvae emerging from the embryo into sterile medium have symmetrical apical and basal membrane conductances while larvae emerging into non-sterile medium have apical membranes fivefold more conductive than basal membranes. The channels inserted into the apical membranes could originate in microbiata or host and mediate recognition of microbes. Entomopathogenic cyclic peptide toxins deplete intracellular ions reversibly, forming transient ion channels that do not conduct water, unlike an ionophore like nystatin that depletes ions irreversibly. We show the feasibility of studying the interaction of a single microbial species, or tractable combinatorials of microbial species, with only enterocytes in the primary epithelial barrier. ABSTRACT Microbiota colonizing exposed epithelial surfaces are vital for sustenance of metazoan life, but communication between microbiota, epithelial cells and the host immune system is only beginning to be understood. We address this issue in the posterior midgut epithelium of Drosophila larvae where nutrient transport and immune functions are exclusively transcellular. We showed that larvae emerging into a sterile post-embryonic environment have symmetrical apical and basal membranes. In contrast, larvae emerging into non-sterile media, the source of microbiota, have markedly asymmetrical membranes, with apical membrane conductance more than fivefold higher than the basal membrane. As an example of pathogen action, we showed that the entomopathogenic fungal toxin destruxin A (Dx) depleted intracellular ions. Reversibility of action of Dx was verified by bilayer reconstitution in forming transient non-specific channels that conduct ions but not water. Dx was also less effective from the apical side as compared to the basal side of the epithelium. We also showed that intercellular septa are not conductive in non-sterile cells, even though most cells are isopotential. Luminal microbiota therefore impart asymmetry to the epithelium, by activation of apical membrane conductance, enhancing inter-enterocyte communication, separated by insulating septa, via the gut lumen. These results also open the possibility of studying the basis of bidirectional molecular conversation specifically between enterocytes and microbiota that enables discrimination between commensals and pathogens, establishment of the former, and elimination of the latter.
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Affiliation(s)
- Shubha R Shanbhag
- Tata Institute of Fundamental Research, Colaba, Mumbai, 400 005, India
| | | | - Abhay Sane
- Tata Institute of Fundamental Research, Colaba, Mumbai, 400 005, India
| | - Natalie M D'Silva
- Tata Institute of Fundamental Research, Colaba, Mumbai, 400 005, India
| | - Subrata Tripathi
- Tata Institute of Fundamental Research, Colaba, Mumbai, 400 005, India.,Institute of Physics, Sachivalaya Marg, Bhubaneswar, 751 005, India
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Agrawal Y, Narwani T, Subramanian S. Genome sequence and comparative analysis of clavicipitaceous insect-pathogenic fungus Aschersonia badia with Metarhizium spp. BMC Genomics 2016; 17:367. [PMID: 27189621 DOI: 10.1186/s12864-016-2710-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 05/05/2016] [Indexed: 11/10/2022] Open
Abstract
Background Aschersonia badia [(Ab) Teleomorph: Hypocrella siamensis] is an entomopathogenic fungus that specifically infects scale insects and whiteflies. We present the whole genome sequence of Ab and its comparison with two clavicipitaceous fungi Metarhizium robertsii (MR: generalist entomopathogen) and M. acridum (MAC: acridid-specific entomopathogen) that exhibit variable host preferences. Here, through comparative analysis of pathogen-host interacting genes, carbohydrate active enzymes, secondary metabolite biosynthesis genes, and sexuality genes, we explore the proteins with possible virulence functions in clavicipitaceous fungi. Comprehensive overview of GH18 family chitinases has been provided to decipher the role of chitinases in claviceptaceous fungi that are either host specific or generalists. Results We report the 28.8 Mb draft genome of Ab and its comparative genome analysis with MR and MAC. The comparative analyses suggests expansion in pathogen-host interacting gene families and carbohydrate active enzyme families in MR, whilst their contraction in Ab and MAC genomes. The multi-modular NRPS gene (dtxS1) responsible for biosynthesis of the secondary metabolite destruxin in MR is not conserved in Ab, similar to the specialist pathogen MAC. An additional siderophore biosynthetic gene responsible for acquisition of iron was identified in MR. Further, the domain survey of chitinases suggest that the CBM50 (LysM) domains, which participate in chitin-binding functions, were not observed in MAC, but were present in Ab and MR. However, apparent differences in frequency of CBM50 domains associated with chitinases of Ab and MR was identified, where MR chitinases displayed a higher proportion of associated CBM50 domains than Ab chitinases. Conclusions This study suggests differences in distribution of dtxS1 and chitinases in specialists (Ab and MAC) and generalists (MR) fungi. Our analysis also suggests the presence of a siderophore biosynthetic gene in the MR genome which perhaps aids in enhanced virulence potential and host range. The variation in association of CBMs, being higher in generalists (MR) and lower in specialists (Ab and MAC) fungi may further be responsible for the differences in host affiliation. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2710-6) contains supplementary material, which is available to authorized users.
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Romans-Fuertes P, Sondergaard TE, Sandmann MI, Wollenberg RD, Nielsen KF, Hansen FT, Giese H, Brodersen DE, Sørensen JL. Identification of the non-ribosomal peptide synthetase responsible for biosynthesis of the potential anti-cancer drug sansalvamide in Fusarium solani. Curr Genet 2016; 62:799-807. [PMID: 26936154 DOI: 10.1007/s00294-016-0584-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Revised: 02/16/2016] [Accepted: 02/18/2016] [Indexed: 12/24/2022]
Abstract
Sansalvamide is a cyclic pentadepsipeptide produced by Fusarium solani and has shown promising results as potential anti-cancer drug. The biosynthetic pathway has until now remained unidentified, but here we used an Agrobacterium tumefaciens-mediated transformation (ATMT) approach to generate knockout mutants of two candidate non-ribosomal peptide synthetases (NRPS29 and NRPS30). Comparative studies of secondary metabolites in the two deletion mutants and wild type confirmed the absence of sansalvamide in the NRPS30 deletion mutant, implicating this synthetase in the biosynthetic pathway for sansalvamide. Sansalvamide is structurally related to the cyclic hexadepsipeptide destruxin, which both contain an α-hydroxyisocaproic acid (HICA) unit. A gene cluster responsible for destruxin production has previously been identified in Metarhizium robertsii together with a hypothetical biosynthetic pathway. Using comparative bioinformatic analyses of the catalytic domains in the destruxin and sansalvamide NRPSs, we were able to propose a model for sansalvamide biosynthesis. Orthologues of the gene clusters were also identified in species from several other genera including Acremonium chrysogenum and Trichoderma virens, which suggests that the ability to produce compounds related to destruxin and sansalvamide is widespread.
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Taibon J, Strasser H. Analytical Methods for Secondary Metabolite Detection. Methods Mol Biol 2016; 1477:191-209. [PMID: 27565501 DOI: 10.1007/978-1-4939-6367-6_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The entomopathogenic fungi Metarhizium brunneum, Beauveria bassiana, and B. brongniartii are widely applied as biological pest control agent in OECD countries. Consequently, their use has to be flanked by a risk management approach, which includes the need to monitor the fate of their relevant toxic metabolites. There are still data gaps claimed by regulatory authorities pending on their identification and quantification of relevant toxins or secondary metabolites. In this chapter, analytical methods are presented allowing the qualitative and quantitative analysis of the relevant toxic B. brongniartii metabolite oosporein and the three M. brunneum relevant destruxin (dtx) derivatives dtx A, dtx B, and dtx E.
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Affiliation(s)
- Judith Taibon
- Institute of Pharmacy, Department of Pharmacognosy, CCB - Centrum of Chemistry and Biomedicine, University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria
- Institute of Microbiology, University of Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria
| | - Hermann Strasser
- Institute of Microbiology, University of Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria.
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