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Shao E, Huang H, Yuan J, Yan Y, Ou L, Chen X, Pan X, Guan X, Sha L. N-Terminal α-Helices in Domain I of Bacillus thuringiensis Vip3Aa Play Crucial Roles in Disruption of Liposomal Membrane. Toxins (Basel) 2024; 16:88. [PMID: 38393166 PMCID: PMC10892741 DOI: 10.3390/toxins16020088] [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: 01/07/2024] [Revised: 01/29/2024] [Accepted: 02/04/2024] [Indexed: 02/25/2024] Open
Abstract
Bacillus thuringiensis Vip3 toxins form a tetrameric structure crucial for their insecticidal activity. Each Vip3Aa monomer comprises five domains. Interaction of the first four α-helices in domain I with the target cellular membrane was proposed to be a key step before pore formation. In this study, four N-terminal α-helix-deleted truncations of Vip3Aa were produced and, it was found that they lost both liposome permeability and insecticidal activity against Spodoptera litura. To further probe the role of domain I in membrane permeation, the full-length domain I and the fragments of N-terminal α-helix-truncated domain I were fused to green fluorescent protein (GFP), respectively. Only the fusion carrying the full-length domain I exhibited permeability against artificial liposomes. In addition, seven Vip3Aa-Cry1Ac fusions were also constructed by combination of α-helices from Vip3Aa domains I and II with the domains II and III of Cry1Ac. Five of the seven combinations were determined to show membrane permeability in artificial liposomes. However, none of the Vip3Aa-Cry1Ac combinations exhibited insecticidal activity due to the significant reduction in proteolytic stability. These results indicated that the N-terminal helix α1 in the Vip3Aa domain I is essential for both insecticidal activity and liposome permeability and that domain I of Vip3Aa preserved a high liposome permeability independently from domains II-V.
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Affiliation(s)
- Ensi Shao
- China National Engineering Research Center of JUNCAO Technology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (E.S.); (J.Y.); (Y.Y.); (L.O.); (X.C.)
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (H.H.); (X.P.); (X.G.)
| | - Hanye Huang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (H.H.); (X.P.); (X.G.)
| | - Jin Yuan
- China National Engineering Research Center of JUNCAO Technology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (E.S.); (J.Y.); (Y.Y.); (L.O.); (X.C.)
| | - Yaqi Yan
- China National Engineering Research Center of JUNCAO Technology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (E.S.); (J.Y.); (Y.Y.); (L.O.); (X.C.)
| | - Luru Ou
- China National Engineering Research Center of JUNCAO Technology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (E.S.); (J.Y.); (Y.Y.); (L.O.); (X.C.)
| | - Xiankun Chen
- China National Engineering Research Center of JUNCAO Technology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (E.S.); (J.Y.); (Y.Y.); (L.O.); (X.C.)
| | - Xiaohong Pan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (H.H.); (X.P.); (X.G.)
| | - Xiong Guan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (H.H.); (X.P.); (X.G.)
| | - Li Sha
- China National Engineering Research Center of JUNCAO Technology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (E.S.); (J.Y.); (Y.Y.); (L.O.); (X.C.)
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (H.H.); (X.P.); (X.G.)
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Hemthanon T, Promdonkoy B, Boonserm P. Screening and characterization of Bacillus thuringiensis isolates for high production of Vip3A and Cry proteins and high thermostability to control Spodoptera spp. J Invertebr Pathol 2023; 201:108020. [PMID: 37956858 DOI: 10.1016/j.jip.2023.108020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 11/04/2023] [Accepted: 11/10/2023] [Indexed: 11/15/2023]
Abstract
Bacillus thuringiensis (Bt) is an entomopathogenic bacterium that produces crystalline (Cry and Cyt) and soluble (vegetative insecticidal proteins or Vips) proteins during the sporulation and vegetative growth phases, respectively. Combining Cry and Vip proteins could delay insect resistance development and exhibit synergistic activity against various insect pests. This study aims to screen Bt isolates collected from Thailand for high Vip3A and Cry protein production levels and high thermostability to control Spodoptera spp. Among the selected Bt isolates with high target protein synthesis, Bt isolate 506 was found to be safe for further biopesticide formulation due to the absence of non-specific metabolite, as determined by the detection of thermo-stable β-exotoxin I based on biological assays and PCR analysis. Bt isolate 506 showed the presence of Cry1A, Cry2A, and Vip3A-type proteins identified as Cry1Aa45, Cry2Aa22, and Vip3A87, respectively. The insecticidal activity of whole culture extracts containing Vip3A and Cry mixtures and culture supernatants containing secreted Vip3A protein was evaluated against the second-instar larvae of S. exigua and S. frugiperda. The Bt isolate 506 showed high toxicity against both insects, and the insecticidal proteins produced by this isolate retained their activity after heating at 50 °C. This Bt isolate is a promising candidate for further development as a biopesticide against lepidopteran pests.
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Affiliation(s)
- Tharathip Hemthanon
- Institute of Molecular Biosciences, Mahidol University, Salaya, Phuttamonthon, Nakhon Pathom 73170, Thailand
| | - Boonhiang Promdonkoy
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Phahonyothin Road, Khlong Luang, Pathumthani 12120, Thailand
| | - Panadda Boonserm
- Institute of Molecular Biosciences, Mahidol University, Salaya, Phuttamonthon, Nakhon Pathom 73170, Thailand.
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Zhao M, Tao Z, Wang L, Wang T, Wang C, Li S, Huang S, Wei Y, Jiang T, Li P. Structural modification of (3E)-4,8-dimethyl-1,3,7-nontriene enhances its ability to kill Plutella xylostella insect pests. PEST MANAGEMENT SCIENCE 2023; 79:3280-3289. [PMID: 37085948 DOI: 10.1002/ps.7508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 03/16/2023] [Accepted: 04/22/2023] [Indexed: 05/03/2023]
Abstract
BACKGROUND Plant secondary metabolites and their modified derivatives play an important role in the discovery and development of novel insecticides. The natural plant product (3E)-4,8-dimethyl-1,3,7-nontriene (DMNT) has been proven to be able to effectively repel and kill the lepidopteran insect pest Plutella xylostella. RESULTS In this study, four oxygenated derivatives of DMNT were synthesized by allylic hydroxylation and subsequent etherification or esterification. Bioassays on P. xylostella larvae showed that the compounds DMNT-OCH3 (2), DMNT-OCy (3) and DMNT-OAc (4) were more toxic to the larvae than DMNT alone. The most pronounced effect was observed for compound 2, which showed a 22.23% increase in lethality at a concentration of 0.25 μm. Moreover, the peritrophic matrix (PM) barrier in the insect midgut was more severely damaged by compounds 2, 3 and 4 than by DMNT. The median lethal concentration (LC50 , 48 h) of compounds 2, 3 and 4 on P. xylostella was determined to be 0.98, 1.13 and 1.11 mg mL-1 , respectively, which is much lower than the commercial insecticides eucalyptol (2.89 mg mL-1 ) and thymol (2.45 mg mL-1 ). CONCLUSION These results suggested that oxygenated DMNT derivatives offer a significantly improved killing effect over DMNT on P. xylostella. This work has provided a basis for further design, structural modification and development of DMNT as botanical insecticides. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Mengjie Zhao
- The National Key Engineering Lab of Crop Stress Resistance Breeding, the School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Zhen Tao
- The National Key Engineering Lab of Crop Stress Resistance Breeding, the School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Ling Wang
- The National Key Engineering Lab of Crop Stress Resistance Breeding, the School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Tengyue Wang
- The National Key Engineering Lab of Crop Stress Resistance Breeding, the School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Chuanhong Wang
- The National Key Engineering Lab of Crop Stress Resistance Breeding, the School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Shuai Li
- The National Key Engineering Lab of Crop Stress Resistance Breeding, the School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Shijie Huang
- The National Key Engineering Lab of Crop Stress Resistance Breeding, the School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Yuming Wei
- The School of Tea and Food Science and Technology, Anhui Agricultural University, Hefei, China
| | - Taoshan Jiang
- The National Key Engineering Lab of Crop Stress Resistance Breeding, the School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Peijin Li
- The National Key Engineering Lab of Crop Stress Resistance Breeding, the School of Life Sciences, Anhui Agricultural University, Hefei, China
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Wang C, Deng Z, Yuan J, Xu K, Sha L, Guan X, Huang Z, Shao E. Removal of an Aminopeptidase N From Midgut Brush Border Does Not Affect Susceptibility of Spodoptera litura (Lepidoptera: Noctuidae) Larvae to Four Insecticidal Proteins of Bacillus thuringiensis (Bacillales: Bacillaceae). JOURNAL OF ECONOMIC ENTOMOLOGY 2023; 116:223-232. [PMID: 36421056 DOI: 10.1093/jee/toac184] [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: 09/07/2022] [Indexed: 06/16/2023]
Abstract
Spodoptera litura is one of the most destructive lepidopteran insects of cabbages and cauliflowers in the world. Cry1 and Vip3 toxins from Bacillus thuringiensis have been reported to show toxicity in multiple lepidopteran insects. Binding of toxic molecules to specific receptors on the midgut epithelial cells is known to be a key step in the action mode of Bt toxins. Aminopeptidase N (APN) -like proteins have been reported to be binding sites of multiple Cry toxins in the midgut of Cry susceptible insects. In the present study, we identified six midgut APNs by analysis of the genome and midgut transcriptome of S. litura. CRISPR/Cas9 mediated gene-knockout system was utilized to mutate the GPI-anchor signal peptide at the C terminus of SlAPN1. SlAPN1 was verified to be removed from the midgut brush border membrane vesicles of a homozygous knockout strain of S. litura (SlAPN1-KO). Bioassay results indicated that susceptibility of the SlAPN1-KO strain to Cry1Aa, Cry1Ac, Cry1Ca, and Vip3Aa toxins was close to that of the wild-type strain of S. litura. RT-qPCR results showed that the transcriptional level of SlAPN2-6 was not up-regulated after knockout of the SlAPN1. Results in this study indicated that the SlAPN1 did not play a critical role in the pathway of toxicity of Cry1Aa, Cry1Ac, Cry1Ca, and Vip3Aa toxins in S. litura.
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Affiliation(s)
- Can Wang
- National Engineering Research Center of JUNCAO Technology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education & Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China
| | - Zhimin Deng
- National Engineering Research Center of JUNCAO Technology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education & Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China
| | - Jin Yuan
- National Engineering Research Center of JUNCAO Technology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education & Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China
| | - Kexin Xu
- National Engineering Research Center of JUNCAO Technology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education & Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China
| | - Li Sha
- National Engineering Research Center of JUNCAO Technology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education & Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China
| | - Xiong Guan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education & Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China
| | - Zhipeng Huang
- National Engineering Research Center of JUNCAO Technology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops & Key Laboratory of Biopesticide and Chemical Biology of Ministry of Education & Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China
| | - Ensi Shao
- National Engineering Research Center of JUNCAO Technology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China
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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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Grizanova EV, Krytsyna TI, Kalmykova GV, Sokolova E, Alikina T, Kabilov M, Coates CJ, Dubovskiy IM. Virulent and necrotrophic strategies of Bacillus thuringiensis in susceptible and resistant insects, Galleria mellonella. Microb Pathog 2023; 175:105958. [PMID: 36572197 DOI: 10.1016/j.micpath.2022.105958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 12/03/2022] [Accepted: 12/21/2022] [Indexed: 12/25/2022]
Abstract
Bacillus thuringiensis (Bt) is one of the most common entomopathogenic bacteria used as a biopesticide, and source of endotoxin genes for generating insect-resistant transgenic plants. The mechanisms underpinning an insect's susceptibility or resistance to B. thuringiensis are diverse. The bacterial lifecycle does not end with the death of a host, they continue to exploit the cadaver to reproduce and sporulate. Herein, we studied the progression of B. thuringiensis subsp. galleriae infection in two populations of wax moth larvae (Galleria mellonella) to gain further insight into the "arms race" between B. thuringiensis virulence and insect defences. Two doses of B. thuringiensis subsp. galleriae (spore and crystalline toxin mixtures) were administered orally to compare the responses of susceptible (S) and resistant (R) populations at ∼30% mortality each. To investigate B. thuringiensis-insect antibiosis, we used a combination of in vivo infection trials, bacterial microbiome analysis, and RNAi targeting the antibacterial peptide gloverin. Within 48 h post-inoculation, B. thuringiensis-resistant insects purged the midgut of bacteria, i.e., colony forming unit numbers fell below detectable levels. Second, B. thuringiensis rapidly modulated gene expression to initiate sporulation (linked to quorum sensing) when exposed to resistant insects in contrast to susceptible G. mellonella. We reinforce earlier findings that elevated levels of antimicrobial peptides, specifically gloverin, are found in the midgut of resistant insects, which is an evolutionary strategy to combat B. thuringiensis infection via its main portal of entry. A sub-population of highly virulent B. thuringiensis can survive the enhanced immune defences of resistant G. mellonella by disrupting the midgut microbiome and switching rapidly to a necrotrophic strategy, prior to sporulation in the cadaver.
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Affiliation(s)
- Ekaterina V Grizanova
- Department of Plant Protection, Novosibirsk State Agrarian University, 630039, Novosibirsk, Russia.
| | - Tatiana I Krytsyna
- Department of Plant Protection, Novosibirsk State Agrarian University, 630039, Novosibirsk, Russia.
| | - Galina V Kalmykova
- Faculty of Physical Engineering, Novosibirsk State Technical University, 630039, Novosibirsk, Russia.
| | - Elina Sokolova
- Department of Plant Protection, Novosibirsk State Agrarian University, 630039, Novosibirsk, Russia.
| | - Tatyana Alikina
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, 630039, Novosibirsk, Russia.
| | - Marsel Kabilov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, 630039, Novosibirsk, Russia.
| | - Christopher J Coates
- Zoology, Ryan Institute, School of Natural Sciences, University of Galway, Galway, H91 TK33, Ireland; Department of Biosciences, Faculty of Science and Engineering, Swansea University, Swansea, SA2 8PP, Wales, UK.
| | - Ivan M Dubovskiy
- Department of Plant Protection, Novosibirsk State Agrarian University, 630039, Novosibirsk, Russia.
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eCry1Gb.1Ig, A Novel Chimeric Cry Protein with High Efficacy against Multiple Fall Armyworm ( Spodoptera frugiperda) Strains Resistant to Different GM Traits. Toxins (Basel) 2022; 14:toxins14120852. [PMID: 36548749 PMCID: PMC9785401 DOI: 10.3390/toxins14120852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/24/2022] [Accepted: 11/26/2022] [Indexed: 12/12/2022] Open
Abstract
Spodoptera frugiperda (fall armyworm, FAW) is one of the most devastating insect pests to corn and soybean production in the Americas and is rapidly expanding its range worldwide. It is known to be hard to control either by chemical insecticide applications or by GM. Although the use of GM traits can be an effective way to control this pest, it is very rare to find native insecticidal proteins that provide the necessary level of FAW control in crop fields where FAW pressure and damage are high. Insecticidal Cry proteins sourced from Bacillus thuringiensis have been heavily utilized in the development of crops with GM traits; however, it is increasingly difficult to identify Cry proteins with unique modes of action. Protein engineering via a phylogenetically guided Cry protein domain swapping approach enabled us to discover novel chimeric Cry proteins engineered from inactive parent sequences. Some of these chimeras show excellent efficacy against key biotypes of FAW from Brazil and North America. In this study, we characterized a Cry-based chimera eCry1Gb.1Ig that is a very potent FAW toxin. eCry1Gb.1Ig showed high efficacy against multiple FAW strains that are resistant to various traits, including Cry1Fa, Vip3Aa and Cry1A.105/Cry2Ab. These results clearly indicate that the FAW strains resistant to Cry1Fa, Vip3Aa or Cry1A.105/Cry2Ab demonstrate no cross-resistance to eCry1Gb.1Ig and strongly suggest that eCry1Gb.1Ig acts through a novel mode of action compared to the existing traits. In addition to its FAW activity, eCry1Gb.1Ig has also been shown to control Chrysodeixis includens (soybean looper, SBL) and Anticarsia gemmatalis (velvetbean caterpillar, VBC), which are significant pests of soybean. When eCry1Gb.1Ig was introduced into corn and soybean crops, transgenic events showed strong efficacy against FAW, SBL and VBC, but no adverse plant phenotypes. This suggests that the in planta expression of the eCry1Gb.1Ig protein does not compromise plant growth or reproduction and can protect plants from FAW-related damage. Therefore, this valuable discovery will provide a differentiating FAW control trait that will give growers another tool to help them reduce yield loss due to FAW.
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Sathyan T, Jayakanthan M, Mohankumar S, Balasubramani V, Kokiladevi E, Ravikesavan R, Kennedy JS, Sathiah N. Genome profiling of an indigenous Bacillus thuringiensis isolate, T405 toxic against the fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae). Microb Pathog 2022; 173:105820. [PMID: 36270440 DOI: 10.1016/j.micpath.2022.105820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 10/02/2022] [Accepted: 10/05/2022] [Indexed: 11/06/2022]
Abstract
In this study, we present the molecular and insecticidal characteristics of an indigenous Bt isolate T405 toxic against the maize fall armyworm (FAW), Spodoptera frugiperda. The presence of cry1, cry2 (cry2Aa & cry2Ab) and vip3A1 genes in T405 was confirmed. The SDS-PAGE gel analysis confirmed the occurrence of Cry and Vip proteins with molecular masses of 130, ∼88 and 65 kDa in T405. LC50 estimates of T405 and HD1 were 161.37 and 910.73 μg ml-1 for neonates whereas, 412.29 and 1014.95 μg ml-1 correspondingly for 2nd instar FAW larvae. Scanning Electron Microscopy depicted the existence of bipyramidal, spherical and cubic crystals in T405 spore suspension. The whole genome sequencing and assembly of T405 produced a total of 563 scaffolds with a genome size of 6,673,691 bp. The BLAST similarity search showed that 12 plasmids were distributed in this genome. Genome annotation revealed the presence of 6174 protein coding genes, 13 rRNA and 98 tRNA, in which 6126 genes were completely annotated for their functions through sequence similarity search, domains/motifs identification and gene ontology studies. Further analysis of these genes identified the presence of many insecticidal toxin protein coding genes viz., cry1Ac32, cry1Ab9, cry1Aa6, cry1Ac5, cry1Aa18, cry1Ab8, cry1Ab11, cry2Aa9, cry1Ia40, cry2Aa9, cry1Ia40, cry2Ab35, cyt, vip3Aa7 and tpp80Aa and several additional virulence assisted factors viz., immune inhibitor A, phospholipase C, sphingomyelinase, cell wall hydrolases, chitinase, hemolysin XhlA and seven urease subunit coding genes (ureA, ureB, ureC, ureD, ureE, ureF, ureG) in the annotated genome.
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Affiliation(s)
- Thiravidamani Sathyan
- Department of Agricultural Entomology, Centre for Plant Protection Studies, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - Mannu Jayakanthan
- Department of Plant Molecular Biology and Bioinformatics, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - Subbarayalu Mohankumar
- Department of Plant Biotechnology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - Venkatasamy Balasubramani
- Department of Plant Biotechnology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - Eswaran Kokiladevi
- Department of Plant Biotechnology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - Rajasekaran Ravikesavan
- Department of Millets, Centre for Plant Breeding and Genetics, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - John Samuel Kennedy
- School of Post Graduate Studies, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - Natarajan Sathiah
- Department of Agricultural Entomology, Centre for Plant Protection Studies, Tamil Nadu Agricultural University, Coimbatore, 641003, India.
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Frattini A, Martínez‐Solís M, Llopis‐Giménez Á, Pozo MJ, Rivero J, Crava CM, Herrero S. Compatibility of mycorrhiza-induced resistance with viral and bacterial entomopathogens in the control of Spodoptera exigua in tomato. PEST MANAGEMENT SCIENCE 2022; 78:4388-4396. [PMID: 35767223 PMCID: PMC9543428 DOI: 10.1002/ps.7058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 06/22/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Arbuscular mycorrhizal fungi (AMF) are soil-borne microorganisms that establish mutualistic associations with roots of most terrestrial plants. This symbiosis results in nutritional and defensive benefits to the host plant, usually conferring protection against biotic stresses, but its indirect impact on third trophic levels is still unknown. In the present work, we explore whether the symbiosis of tomato plants with Funneliformis mosseae (and/or exposition to herbivory) influences the interaction of the generalist pest Spodoptera exigua (Lepidoptera: Noctuidae) with bacterial (Bacillus thuringiensis) and viral (baculovirus, SeMNPV) natural entomopathogens. RESULTS Symbiosis with AMF and previous herbivory reduces the relative growth of S. exigua, increases its susceptibility to a sublethal dose of B. thuringiensis and has positive or neutral impact on the lethality of SeMNPV. Reduction of the phenoloxidase activity, a marker of the insect immune response, was associated with the larval feeding on plant material previously exposed to herbivory but not to the AMF. In addition, no changes in the insect gut microbiota could be associated with the observed changes in larval growth and susceptibility to the entomopathogens. CONCLUSION Our findings provide the first evidence of compatibility of AMF symbiosis in tomato with the use of bacterial and viral entomopathogens, contributing to the development of novel approaches to combine the beneficial effect of AMF and entomopathogens in biological pest control. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
- Ada Frattini
- Department of Genetics and University Institute of Biotechnology and Biomedicine (BIOTECMED)Universitat de ValènciaValenciaSpain
| | - María Martínez‐Solís
- Department of Genetics and University Institute of Biotechnology and Biomedicine (BIOTECMED)Universitat de ValènciaValenciaSpain
| | - Ángel Llopis‐Giménez
- Department of Genetics and University Institute of Biotechnology and Biomedicine (BIOTECMED)Universitat de ValènciaValenciaSpain
| | - María J. Pozo
- Department of Soil Microbiology and Symbiotic SystemsEstación Experimental del Zaidín – Consejo Superior de Investigaciones CientíficasGranadaSpain
| | - Javier Rivero
- Department of Soil Microbiology and Symbiotic SystemsEstación Experimental del Zaidín – Consejo Superior de Investigaciones CientíficasGranadaSpain
| | - Cristina M. Crava
- Department of Genetics and University Institute of Biotechnology and Biomedicine (BIOTECMED)Universitat de ValènciaValenciaSpain
| | - Salvador Herrero
- Department of Genetics and University Institute of Biotechnology and Biomedicine (BIOTECMED)Universitat de ValènciaValenciaSpain
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Li Q, Li M, Zhu M, Zhong J, Wen L, Zhang J, Zhang R, Gao Q, Yu XQ, Lu Y. Genome-wide identification and comparative analysis of Cry toxin receptor families in 7 insect species with a focus on Spodoptera litura. INSECT SCIENCE 2022; 29:783-800. [PMID: 34405540 DOI: 10.1111/1744-7917.12961] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/30/2021] [Accepted: 08/12/2021] [Indexed: 06/13/2023]
Abstract
Cadherin, aminopeptidase N (APN) and alkaline phosphatase (ALP) have been characterized as Cry receptors. In this study, comparative genomic analysis of the 3 receptor families was performed in 7 insects. ALPs and APNs are divided into three and eight clades in phylogenetic trees, respectively. ALPs in clade 3 and APNs in clade 1 contain multiple paralogs within each species and most paralogs are located closely in chromosomes. Drosophila melanogaster has expanded APNs in clade 5 and were lowly expressed in midgut. Cadherins are divided into 16 clades; they may diverge before holometabolous insect speciation except for BtR and Cad89D-like clades. Eight insects from different orders containing BtR orthologs are sensitive to Cry1A or Cry3A, while five species without BtR are insensitive to both toxins. Most APNs in clade 1, several ALPs in clade 3, BtR and Cad89D-like genes were highly or moderately expressed in larval midgut of Spodoptera litura and the other six species, and several members in these clades have been identified as Cry receptors. Expressions of putative S. litura Cry receptors in the midgut after exposing to Bt toxins were also analyzed.
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Affiliation(s)
- Qilin Li
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Mengge Li
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Mengyao Zhu
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Jielai Zhong
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Liang Wen
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Jie Zhang
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Ruonan Zhang
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Qiang Gao
- College of Biology, Hunan University, Changsha, 410082, China
| | - Xiao-Qiang Yu
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Yuzhen Lu
- Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
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11
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Hernández-Martínez P, Bretsnyder EC, Baum JA, Haas JA, Head GP, Jerga A, Ferré J. Comparison of in vitro and in vivo binding site competition of Bacillus thuringiensis Cry1 proteins in two important maize pests. PEST MANAGEMENT SCIENCE 2022; 78:1457-1466. [PMID: 34951106 DOI: 10.1002/ps.6763] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 12/17/2021] [Accepted: 12/23/2021] [Indexed: 06/14/2023]
Abstract
BACKGROUND Binding site models, derived from in vitro competition binding studies, have been widely used for predicting potential cross-resistance among insecticidal proteins from Bacillus thuringiensis. However, because discrepancies have been found between binding data and observed cross-resistance patterns in some insect species, new tools are required to study the functional relevance of the shared binding sites. RESULTS Here, an in vivo approach has been applied to the competition studies to establish the functional relevance of shared binding sites as determined by in vitro competition assays. Using Cry disabled proteins as competitors in mixed protein overlay assays, we assessed the preference of Cry1Ab, Cry1Fa, and Cry1A.105 proteins for shared binding sites in vivo in two important corn pests, Ostrinia nubilalis and Spodoptera frugiperda. CONCLUSION This study shows that in vivo and in vitro binding site competition assays can provide useful information to better ascertain whether different Cry proteins share binding sites and, consequently, whether cross-resistance due to binding site alteration can occur. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
- Patricia Hernández-Martínez
- Department of Genetics, University Institute of Biotechnology and Biomedicine, University of Valencia, Burjassot, Spain
| | - Eric C Bretsnyder
- Plant Biotechnology Program, Bayer Crop Science, Chesterfield, MO, USA
| | - James A Baum
- Plant Biotechnology Program, Bayer Crop Science, Chesterfield, MO, USA
| | - Jeff A Haas
- Plant Biotechnology Program, Bayer Crop Science, Chesterfield, MO, USA
| | - Graham P Head
- Plant Biotechnology Program, Bayer Crop Science, Chesterfield, MO, USA
| | - Agoston Jerga
- Plant Biotechnology Program, Bayer Crop Science, Chesterfield, MO, USA
| | - Juan Ferré
- Department of Genetics, University Institute of Biotechnology and Biomedicine, University of Valencia, Burjassot, Spain
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12
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Güney G, Cedden D, Hänniger S, Heckel DG, Coutu C, Hegedus DD, Mutlu DA, Suludere Z, Sezen K, Güney E, Toprak U. Silencing of an ABC transporter, but not a cadherin, decreases the susceptibility of Colorado potato beetle larvae to Bacillus thuringiensis ssp. tenebrionis Cry3Aa toxin. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2021; 108:e21834. [PMID: 34288075 DOI: 10.1002/arch.21834] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 06/24/2021] [Accepted: 07/02/2021] [Indexed: 06/13/2023]
Abstract
The Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae), is a major pest of potato plants worldwide and is notorious for its ability to develop resistance to insecticides. Cry3 toxins synthesized by Bacillus thuringiensis ssp. tenebrionis have been used successfully to manage this pest. Resistance to Cry toxins is a concerning problem for many insect pests; therefore, it is important to determine the mechanisms by which insects acquire resistance to these toxins. Cadherin-like and ABC transporter proteins have been implicated in the mode of action of Cry toxins as mutations in these genes render lepidopterans resistant to them; however, clear consensus does not exist on whether these proteins also play a role in Cry3 toxin activity and/or development of resistance in coleopterans. In the current study, we identified the L. decemlineata orthologues of the cadherin (LdCAD) and the ABCB transporter (LdABCB1) that have been implicated in the mode of action of Cry toxins in other coleopterans. Suppression of LdABCB1 via RNA interference reduced toxin-related larval mortality, whereas partial silencing of LdCAD did not. Our results suggest that the ABCB is involved in the mode of action of Cry3Aa toxins; however, no evidence was found to support the role of cadherin as a receptor of Cry3Aa in L. decemlineata.
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Affiliation(s)
- Gözde Güney
- Molecular Entomology Lab, Department of Plant Protection, Faculty of Agriculture, Ankara University, Ankara, Turkey
- Max Planck Institute for Chemical Ecology, Jena, Germany
- Agriculture and Agri-Food Canada, Saskatoon, Saskatchewan, Canada
| | - Doğa Cedden
- Molecular Entomology Lab, Department of Plant Protection, Faculty of Agriculture, Ankara University, Ankara, Turkey
| | | | - David G Heckel
- Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Cathy Coutu
- Agriculture and Agri-Food Canada, Saskatoon, Saskatchewan, Canada
| | - Dwayne D Hegedus
- Agriculture and Agri-Food Canada, Saskatoon, Saskatchewan, Canada
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | | | | | - Kazım Sezen
- Department of Biology, Karadeniz Technical University, Trabzon, Turkey
| | - Ebru Güney
- Department of Biology, Karadeniz Technical University, Trabzon, Turkey
| | - Umut Toprak
- Molecular Entomology Lab, Department of Plant Protection, Faculty of Agriculture, Ankara University, Ankara, Turkey
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13
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Ramos LFC, Rangel JHDO, Andrade GC, Lixa C, de Castilho LVA, Nogueira FCS, Pinheiro AS, Gomes FM, AnoBom CD, Almeida RV, de Oliveira DMP. Identification and recombinant expression of an antimicrobial peptide (cecropin B-like) from soybean pest Anticarsia gemmatalis. J Venom Anim Toxins Incl Trop Dis 2021; 27:e20200127. [PMID: 33796137 PMCID: PMC7970720 DOI: 10.1590/1678-9199-jvatitd-2020-0127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 01/11/2021] [Indexed: 11/22/2022] Open
Abstract
ABSTRACT BACKGROUND Insects can be found in numerous diverse environments, being exposed to pathogenic organisms like fungi and bacteria. Once these pathogens cross insect physical barriers, the innate immune system operates through cellular and humoral responses. Antimicrobial peptides are small molecules produced by immune signaling cascades that develop an important and generalist role in insect defenses against a variety of microorganisms. In the present work, a cecropin B-like peptide (AgCecropB) sequence was identified in the velvetbean caterpillar Anticarsia gemmatalis and cloned in a bacterial plasmid vector for further heterologous expression and antimicrobial tests. METHODS AgCecropB sequence (without the signal peptide) was cloned in the plasmid vector pET-M30-MBP and expressed in the Escherichia coli BL21(DE3) expression host. Expression was induced with IPTG and a recombinant peptide was purified using two affinity chromatography steps with Histrap column. The purified peptide was submitted to high-resolution mass spectrometry (HRMS) and structural analyses. Antimicrobial tests were performed using gram-positive (Bacillus thuringiensis) and gram-negative (Burkholderia kururiensis and E. coli) bacteria. RESULTS AgCecropB was expressed in E. coli BL21 (DE3) at 28°C with IPTG 0.5 mM. The recombinant peptide was purified and enriched after purification steps. HRMS confirmed AgCrecropB molecular mass (4.6 kDa) and circular dichroism assay showed α-helix structure in the presence of SDS. AgCrecropB inhibited almost 50% of gram-positive B. thuringiensis bacteria growth. CONCLUSIONS The first cecropin B-like peptide was described in A. gemmatalis and a recombinant peptide was expressed using a bacterial platform. Data confirmed tertiary structure as predicted for the cecropin peptide family. AgCecropB was capable to inhibit B. thuringiensis growth in vitro.
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Affiliation(s)
- Luís Felipe Costa Ramos
- Department of Biochemistry, Institute of Chemistry, Center of Mathematical and Natural Sciences, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - João Henrique de Oliveira Rangel
- Department of Biochemistry, Institute of Chemistry, Center of Mathematical and Natural Sciences, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Guilherme Caldas Andrade
- Department of Biochemistry, Institute of Chemistry, Center of Mathematical and Natural Sciences, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Carolina Lixa
- Department of Biochemistry, Institute of Chemistry, Center of Mathematical and Natural Sciences, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Livia Vieira Araujo de Castilho
- Department of Biochemistry, Institute of Chemistry, Center of Mathematical and Natural Sciences, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
- Alberto Luiz Coimbra Institute of Graduate Studies and Research (COPPE), Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Fábio César Sousa Nogueira
- Department of Biochemistry, Institute of Chemistry, Center of Mathematical and Natural Sciences, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Anderson S Pinheiro
- Department of Biochemistry, Institute of Chemistry, Center of Mathematical and Natural Sciences, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Fabio Mendonça Gomes
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Cristiane Dinis AnoBom
- Department of Biochemistry, Institute of Chemistry, Center of Mathematical and Natural Sciences, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Rodrigo Volcan Almeida
- Department of Biochemistry, Institute of Chemistry, Center of Mathematical and Natural Sciences, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Danielle Maria Perpétua de Oliveira
- Department of Biochemistry, Institute of Chemistry, Center of Mathematical and Natural Sciences, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
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Chen C, Chen H, Huang S, Jiang T, Wang C, Tao Z, He C, Tang Q, Li P. Volatile DMNT directly protects plants against Plutella xylostella by disrupting the peritrophic matrix barrier in insect midgut. eLife 2021; 10:63938. [PMID: 33599614 PMCID: PMC7924945 DOI: 10.7554/elife.63938] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 02/17/2021] [Indexed: 12/14/2022] Open
Abstract
Insect pests negatively affect crop quality and yield; identifying new methods to protect crops against insects therefore has important agricultural applications. Our analysis of transgenic Arabidopsis thaliana plants showed that overexpression of pentacyclic triterpene synthase 1, encoding the key biosynthetic enzyme for the natural plant product (3E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), led to a significant resistance against a major insect pest, Plutella xylostella. DMNT treatment severely damaged the peritrophic matrix (PM), a physical barrier isolating food and pathogens from the midgut wall cells. DMNT repressed the expression of PxMucin in midgut cells, and knocking down PxMucin resulted in PM rupture and P. xylostella death. A 16S RNA survey revealed that DMNT significantly disrupted midgut microbiota populations and that midgut microbes were essential for DMNT-induced killing. Therefore, we propose that the midgut microbiota assists DMNT in killing P. xylostella. These findings may provide a novel approach for plant protection against P. xylostella.
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Affiliation(s)
- Chen Chen
- The National Key Engineering Lab of Crop Stress Resistance Breeding, the School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Hongyi Chen
- The National Key Engineering Lab of Crop Stress Resistance Breeding, the School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Shijie Huang
- The National Key Engineering Lab of Crop Stress Resistance Breeding, the School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Taoshan Jiang
- The National Key Engineering Lab of Crop Stress Resistance Breeding, the School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Chuanhong Wang
- The National Key Engineering Lab of Crop Stress Resistance Breeding, the School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Zhen Tao
- The National Key Engineering Lab of Crop Stress Resistance Breeding, the School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Chen He
- The National Key Engineering Lab of Crop Stress Resistance Breeding, the School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Qingfeng Tang
- Key Laboratory of Biology and Sustainable Management of Plant Diseases and Pests of Anhui Higher Education Institutes, the School of Plant Protection, Anhui Agricultural University, Hefei, China
| | - Peijin Li
- The National Key Engineering Lab of Crop Stress Resistance Breeding, the School of Life Sciences, Anhui Agricultural University, Hefei, China
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Immunosuppressive Activities of Novel PLA 2 Inhibitors from Xenorhabdus hominickii, an Entomopathogenic Bacterium. INSECTS 2020; 11:insects11080505. [PMID: 32759864 PMCID: PMC7469199 DOI: 10.3390/insects11080505] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/03/2020] [Accepted: 08/03/2020] [Indexed: 01/27/2023]
Abstract
Simple Summary Insect immune responses defend fatal attacks from entomopathogens. A Gram-negative Xenorhabdus hominickii exhibits high entomopathogenicity against lepidopteran insects. During the pathogenic processes, the bacteria suppress host insect immune responses by inhibiting phospholipase A2 (PLA2) enzyme activity with the bacterial secondary metabolites. PLA2 catalyzes eicosanoid biosynthesis. Eicosanoids mediate both cellular and humoral immune responses against various insect pathogens. This study identified eight different PLA2 inhibitors from the bacterial culture broth. Butanol extract of the culture broth possessed high potency to inhibit PLA2 activity. Subsequent fractionations led to identification of eight different compounds. The synthetic compounds also showed PLA2 inhibition and insecticidal activities. Furthermore, the addition of the bacterial PLA2 inhibitors significantly enhance other bacterial pathogenicity, suggesting its potential to be applied for developing novel insecticides. Abstract Eicosanoids mediate both cellular and humoral immune responses in insects. Phospholipase A2 (PLA2) catalyzes the first committed step in eicosanoid biosynthesis. It is a common pathogenic target of two entomopathogenic bacteria, Xenorhabdus and Photorhabdus. The objective of this study was to identify novel PLA2 inhibitors from X. hominickii and determine their immunosuppressive activities. To identify novel PLA2 inhibitors, stepwise fractionation of X. hominickii culture broth and subsequent enzyme assays were performed. Eight purified fractions of bacterial metabolites were obtained. Gas chromatography and mass spectrometry (GC-MS) analysis predicted that the main components in these eight fractions were 2-cyanobenzoic acid, dibutylamine, 2-ethyl 1-hexanol, phthalimide (PM), dioctyl terephthalate, docosane, bis (2-ethylhexyl) phthalate, and 3-ethoxy-4-methoxyphenol (EMP). Their synthetic compounds inhibited the activity of PLA2 in hemocytes of a lepidopteran insect, Spodoptera exigua, in a dose-dependent manner. They also showed significant inhibitory activities against immune responses such as prophenoloxidase activation and hemocytic nodulation of S. exigua larvae, with PM and EMP exhibiting the most potent inhibitory activities. These immunosuppressive activities were specific through PLA2 inhibition because an addition of arachidonic acid, a catalytic product of PLA2, significantly rescued such suppressed immune responses. The two most potent compounds (PM and EMP) showed significant insecticidal activities after oral administration. When the compounds were mixed with Bacillus thuringiensis (Bt), they markedly increased Bt pathogenicity. This study identified eight PLA2 inhibitors from bacterial metabolites of X. hominickii and demonstrated their potential as novel insecticides.
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Wang J, Wang J, He J, Wu J, Sun J, Wang R, Zhang W. Vip3Aa from Bacillus thuringiensis subsp. kurstaki HD1 is toxic to Aedes aegypti (Diptera: Culicidae). J Invertebr Pathol 2020; 171:107342. [DOI: 10.1016/j.jip.2020.107342] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 01/14/2020] [Accepted: 02/08/2020] [Indexed: 01/25/2023]
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Ren X, Wang Y, Ma Y, Jiang W, Ma X, Hu H, Wang D, Ma Y. Midgut de novo transcriptome analysis and gene expression profiling of Spodoptera exigua larvae exposed with sublethal concentrations of Cry1Ca protein. 3 Biotech 2020; 10:138. [PMID: 32158634 DOI: 10.1007/s13205-020-2129-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 02/11/2020] [Indexed: 12/01/2022] Open
Abstract
Spodoptera exigua (Hübner) is a polyphagous pest on agricultural crops, whose control is based mainly on the application of chemical insecticides. Bacillus thuringiensis (Bt) is one of the most important biological agents that have been successfully applied as a biological control, and Cry1Ca protein is considered to be active against S. exigua. Therefore, to understand the response of S. exigua to Cry1Ca protein, high-throughput sequencing was used to analyse the S. exigua larval midgut after treatment with sublethal concentrations of Cry1Ca protein. Transcriptome data showed that a total of 98,571 unigenes with an N50 value of 1135 bp and a mean length of 653 bp were obtained. Furthermore, 2962 differentially expressed genes (DEGs) were identified after Cry1Ca challenge, including 1508 up-regulated and 1454 down-regulated unigenes. Among these DEGs, detoxification (CYP, CarE, and GST) and Bt resistance (ALP, APN, and ABC transporter)-related genes were differentially expressed in the midgut of S. exigua after Cry1Ca treatment. However, most DEGs of protective enzymes were down-regulated, while most DEGs related with serine protease and REPAT were up-regulated. Furthermore, almost all DEGs related to the immune signaling pathway, antimicrobial protein, and lysozyme were up-regulated by Cry1Ca treatment. These results indicated that the detoxification enzyme, protective enzymes, Bt resistance-related genes, serine protease, REPAT, and the immune response might have been involved in the response of S. exigua to Cry1Ca protein. In summary, analysis of the transcriptomal expression of genes involved in Cry1Ca protein against S. exigua provided potential clues for elucidating the host response processes and defensive mechanisms underlying Cry1Ca toxicity.
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Affiliation(s)
- Xiangliang Ren
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of CAAS, Anyang, 455000 Henan China
| | - Yingying Wang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of CAAS, Anyang, 455000 Henan China
- Honghu Agricultural Technology Extension Center, Jingzhou, 433200 Hubei China
| | - Yajie Ma
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of CAAS, Anyang, 455000 Henan China
| | - Weili Jiang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of CAAS, Anyang, 455000 Henan China
| | - Xiaoyan Ma
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of CAAS, Anyang, 455000 Henan China
| | - Hongyan Hu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of CAAS, Anyang, 455000 Henan China
| | - Dan Wang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of CAAS, Anyang, 455000 Henan China
| | - Yan Ma
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of CAAS, Anyang, 455000 Henan China
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The role of midgut nonspecific esterase in the susceptibility of Galleria mellonella larvae to Bacillus thuringiensis. J Invertebr Pathol 2019; 166:107208. [DOI: 10.1016/j.jip.2019.107208] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 06/06/2019] [Accepted: 06/12/2019] [Indexed: 11/20/2022]
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19
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Chen CY, Bouwer G. The compatibility of Bacillus thuringiensis Cry protein-solubilizing buffers with the droplet feeding method in fall armyworm larvae. J Invertebr Pathol 2019; 166:107233. [PMID: 31437438 DOI: 10.1016/j.jip.2019.107233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 08/08/2019] [Accepted: 08/18/2019] [Indexed: 11/27/2022]
Abstract
The volumes of alkaline (pH > 10), Bacillus thuringiensis Cry protein-solubilizing buffers imbibed by fall armyworm larvae in droplet feeding assays were determined. The buffers differed in the presence or concentration of key ingredients, including buffering agents, chelating agents, reducing agents, and protease inhibitors. For both first and second instar larvae, the buffer used had a significant effect on the volume imbibed. The study showed that the droplet feeding method is compatible with Cry protein-solubilizing buffers, but that it is important to determine the volume imbibed for every buffer used in dose-dependent bioassays in order to reduce dose errors.
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Affiliation(s)
- Chia-Yu Chen
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa
| | - Gustav Bouwer
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa.
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Boonmee K, Thammasittirong SNR, Thammasittirong A. Molecular characterization of lepidopteran-specific toxin genes in Bacillus thuringiensis strains from Thailand. 3 Biotech 2019; 9:117. [PMID: 30854277 DOI: 10.1007/s13205-019-1646-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 02/21/2019] [Indexed: 01/14/2023] Open
Abstract
A total of 511 local isolates of Bacillus thuringiensis from different geographical regions of Thailand were analyzed for the presence of the cry1A, cry1B, cry2A, cry9, and vip3A genes encoding for lepidopteran-specific toxins. PCR results revealed that 94.32% (482/511) of B. thuringiensis isolates harbored at least one of the detected genes, of which the cry1A, cry1B, cry2A, cry9, and vip3A genes were detected at frequencies of 90.61%, 89.63%, 76.32%, 40.70%, and 48.18%, respectively. Nineteen gene-combination profiles were discovered among 482 B. thuringiensis isolates, of which the most frequently detected profile contained the cry1A, cry1B, cry2A, and vip3A genes. Sixty-one isolates (12.66%), which harbored all of the detected insecticidal toxin genes, were further detected for the exochitinase (chi36) gene and chitinase activity. The results revealed that all 61 isolates contained the chi36 gene and exhibited chitinase activity. Insect bioassays showed that five isolates were highly toxic (more than 80% mortality) against second instar larvae of Spodoptera litura, of which the highest insect mortality (93%) was obtained from the B. thuringiensis isolates 225-15 and 417-1. Scanning electron microscopy revealed that the crystal morphologies of the five effective isolates were bipyramidal and cuboidal shapes. SDS-PAGE analysis of the spore-crystal mixture showed major bands of approximately 65 and 130 kDa. These five effective strains are alternative candidates for use as a microbial insecticide for the control of the S. litura pest.
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Affiliation(s)
- Kesorn Boonmee
- 1Department of Microbiology, Faculty of Liberal Arts and Science, Kasetsart University, Nakhon Pathom, 73140 Thailand
| | - Sutticha Na-Ranong Thammasittirong
- 1Department of Microbiology, Faculty of Liberal Arts and Science, Kasetsart University, Nakhon Pathom, 73140 Thailand
- 2Microbial Biotechnology Unit, Faculty of Liberal Arts and Science, Kasetsart University, Nakhon Pathom, 73140 Thailand
| | - Anon Thammasittirong
- 1Department of Microbiology, Faculty of Liberal Arts and Science, Kasetsart University, Nakhon Pathom, 73140 Thailand
- 2Microbial Biotechnology Unit, Faculty of Liberal Arts and Science, Kasetsart University, Nakhon Pathom, 73140 Thailand
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Pinos D, Martínez-Solís M, Herrero S, Ferré J, Hernández-Martínez P. The Spodoptera exigua ABCC2 Acts as a Cry1A Receptor Independently of its Nucleotide Binding Domain II. Toxins (Basel) 2019; 11:toxins11030172. [PMID: 30909393 PMCID: PMC6468857 DOI: 10.3390/toxins11030172] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 03/18/2019] [Accepted: 03/20/2019] [Indexed: 12/27/2022] Open
Abstract
ABC proteins are primary-active transporters that require the binding and hydrolysis of ATP to transport substrates across the membrane. Since the first report of an ABCC2 transporter as receptor of Cry1A toxins, the number of ABC transporters known to be involved in the mode of action of Cry toxins has increased. In Spodoptera exigua, a mutation in the SeABCC2 gene is described as genetically linked to resistance to the Bt-product XentariTM. This mutation affects an intracellular domain involved in ATP binding, but not the extracellular loops. We analyzed whether this mutation affects the role of the SeABCC2 as a functional receptor to Cry1A toxins. The results show that Sf21 cells expressing the truncated form of the transporter were susceptible to Cry1A toxins. Moreover, specific Cry1Ac binding was observed in those cells expressing the truncated SeABCC2. Additionally, no differences in the irreversible Cry1Ac binding component (associated with the toxin insertion into the membrane) were observed when tested in Sf21 cells expressing either the full-length or the truncated form of the SeABCC2 transporter. Therefore, our results point out that the partial lack of the nucleotide binding domain II in the truncated transporter does not affect its functionality as a Cry1A receptor.
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Affiliation(s)
- Daniel Pinos
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain.
| | - María Martínez-Solís
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain.
| | - Salvador Herrero
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain.
| | - Juan Ferré
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain.
| | - Patricia Hernández-Martínez
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain.
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Soares Figueiredo C, Nunes Lemes AR, Sebastião I, Desidério JA. Synergism of the Bacillus thuringiensis Cry1, Cry2, and Vip3 Proteins in Spodoptera frugiperda Control. Appl Biochem Biotechnol 2019; 188:798-809. [DOI: 10.1007/s12010-019-02952-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/11/2019] [Indexed: 12/17/2022]
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Martínez-Solís M, Pinos D, Endo H, Portugal L, Sato R, Ferré J, Herrero S, Hernández-Martínez P. Role of Bacillus thuringiensis Cry1A toxins domains in the binding to the ABCC2 receptor from Spodoptera exigua. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 101:47-56. [PMID: 30077769 DOI: 10.1016/j.ibmb.2018.07.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 07/24/2018] [Accepted: 07/29/2018] [Indexed: 06/08/2023]
Abstract
Cry proteins from Bacillus thuringiensis (Bt) have been used to control insect pests either as formulated sprays or as in Bt-crops. However, field-evolved resistance to Bt proteins is threatening the long-term use of Bt products. The SeABCC2 locus has been genetically linked to resistance to a Bt bioinsecticide (Xentari™) in Spodoptera exigua (a mutation producing a truncated form of the transporter lacking an ATP binding domain was found in the resistant insects). Here, we investigated the role of SeABCC2 in the mode of action of Cry1Aa, Cry1Ab, Cry1Ac, Cry1Ca, and two Cry1A-1Ca hybrids by expressing the receptor in Sf21 and HEK293T cell lines. Cell toxicity assays showed that Sf21 cells expressing SeABCC2 become susceptible to Cry1A proteins. HEK293T cells expressing the transporter were found susceptible to Cry1A proteins but not to Cry1Ca. The results with the Cry1A-1Ca hybrids suggest that domain II from Cry1Ab/c is crucial for the toxicity to Sf21 cells, whereas domain III from Cry1Aa/b is crucial for the toxicity to HEK293T cells. Binding assays showed that the Cry1Ac binding is of high affinity and specific to cells expressing the SeABCC2 transporter. Heterologous competition experiments support a model in which domain II of Cry1Ab/c has a common binding site in the SeABCC2 protein, whereas domain III of Cry1Aa/b binds to a different binding site in the SeABCC2 protein.
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Affiliation(s)
- María Martínez-Solís
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain
| | - Daniel Pinos
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain
| | - Haruka Endo
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
| | - Leivi Portugal
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca 62250, Morelos, Mexico
| | - Ryoichi Sato
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
| | - Juan Ferré
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain
| | - Salvador Herrero
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain
| | - Patricia Hernández-Martínez
- ERI de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain.
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Changes in gene expression and apoptotic response in Spodoptera exigua larvae exposed to sublethal concentrations of Vip3 insecticidal proteins. Sci Rep 2017; 7:16245. [PMID: 29176692 PMCID: PMC5701239 DOI: 10.1038/s41598-017-16406-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 11/12/2017] [Indexed: 01/24/2023] Open
Abstract
The insecticidal Vip3 proteins from Bacillus thuringiensis (Bt), along with the classical Bt Cry proteins, are currently used in Bt-crops to control insect pests, since they do not share the same mode of action. Here we characterized the response of Spodoptera exigua larvae after Vip3 challenge. The expression profile of 47 genes was analyzed in larvae challenged with three concentrations of Vip3Ca. Results showed that the up-regulated genes were mainly involved in immune response, whereas the down-regulated genes were mainly involved in the digestion process. Other mechanisms of cellular response to the damage such as apoptosis were analyzed. For this analysis, sections from the midguts were examined by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. The nuclei of the midgut epithelial cells were stained at the highest concentration of the Vip3Ca protein and at lower concentrations of Vip3Aa in agreement with the different potency of the two proteins. In addition, apoptosis was also examined by the analysis of the expression of five caspase genes. The present study shows that exposure of S. exigua larvae to sublethal concentrations of Vip3 proteins activates different insect response pathways which trigger the regulation of some genes, APN shedding, and apoptotic cell death.
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Bel Y, Sheets JJ, Tan SY, Narva KE, Escriche B. Toxicity and Binding Studies of Bacillus thuringiensis Cry1Ac, Cry1F, Cry1C, and Cry2A Proteins in the Soybean Pests Anticarsia gemmatalis and Chrysodeixis (Pseudoplusia) includens. Appl Environ Microbiol 2017; 83:e00326-17. [PMID: 28363958 PMCID: PMC5440703 DOI: 10.1128/aem.00326-17] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 03/23/2017] [Indexed: 11/20/2022] Open
Abstract
Anticarsia gemmatalis (velvetbean caterpillar) and Chrysodeixis includens (soybean looper, formerly named Pseudoplusia includens) are two important defoliating insects of soybeans. Both lepidopteran pests are controlled mainly with synthetic insecticides. Alternative control strategies, such as biopesticides based on the Bacillus thuringiensis (Bt) toxins or transgenic plants expressing Bt toxins, can be used and are increasingly being adopted. Studies on the insect susceptibilities and modes of action of the different Bt toxins are crucial to determine management strategies to control the pests and to delay outbreaks of insect resistance. In the present study, the susceptibilities of both soybean pests to the Bt toxins Cry1Ac, Cry1Fa, Cry1Ca, and Cry2Aa have been investigated. Bioassays performed in first-instar larvae showed that both insects are susceptible to all these toxins. Competition-binding studies carried out with Cry1Ac and Cry1Fa 125-iodine labeled proteins demonstrated the presence of specific binding sites for both of them on the midgut brush border membrane vesicles (BBMVs) of both A. gemmatalis and C. includens Competition-binding experiments and specific-binding inhibition studies performed with selected sugars and lectins indicated that Cry1Ac and Cry1Fa share some, but not all, binding sites in the midguts of both insects. Also, the Cry1Ac- or Cry1Fa-binding sites were not shared with Cry1Ca or Cry2Aa in either soybean pest. This study contributes to the knowledge of Bt toxicity and midgut toxin binding sites in A. gemmatalis and C. includens and sheds light on the cross-resistance potential of Cry1Ac, Cry1Fa, Cry1Ca, and Cry2Aa Bt proteins as candidate proteins for Bt-pyramided crops.IMPORTANCE In the present study, the toxicity and the mode of action of the Bacillus thuringiensis (Bt) toxins Cry1Ac, Cry1Fa, Cry1Ca, and Cry2Aa in Anticarsia gemmatalis and Chrysodeixis includens (important defoliating pests of soybeans) have been investigated. These studies are crucial for determining management strategies for pest control. Bioassays showed that both insects were susceptible to the toxins. Competition-binding studies demonstrated the presence of Cry1Fa- and Cry1Ac-specific binding sites in the midguts of both pests. These results, together with the results from binding inhibition studies performed with sugars and lectins, indicated that Cry1Ac and Cry1Fa share some, but not all, binding sites, and that they were not shared with Cry1Ca or Cry2Aa in either soybean pest. This study contributes to the knowledge of Bt toxicity in A. gemmatalis and C. includens and sheds light on the cross-resistance potential of Cry1Ac, Cry1Fa, Cry1Ca, and Cry2Aa Bt proteins as candidate proteins for Bt-pyramided crops.
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Affiliation(s)
- Yolanda Bel
- Department of Genetics, Universitat de València, Burjassot, Spain
- Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BioTecMed), Universitat de València, Burjassot, Spain
| | | | - Sek Yee Tan
- Dow AgroSciences, Indianapolis, Indiana, USA
| | | | - Baltasar Escriche
- Department of Genetics, Universitat de València, Burjassot, Spain
- Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BioTecMed), Universitat de València, Burjassot, Spain
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Zhao M, Yuan X, Wei J, Zhang W, Wang B, Myint Khaing M, Liang G. Functional roles of cadherin, aminopeptidase-N and alkaline phosphatase from Helicoverpa armigera (Hübner) in the action mechanism of Bacillus thuringiensis Cry2Aa. Sci Rep 2017; 7:46555. [PMID: 28488696 PMCID: PMC5424343 DOI: 10.1038/srep46555] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 03/17/2017] [Indexed: 11/08/2022] Open
Abstract
A pyramid strategy combining the Cry1A and Cry2A toxins in Bt crops has been widely used throughout the world to delay pest adaption to transgenic crops and broaden the insecticidal spectrum. Midgut membrane-bound cadherin (CAD), aminopeptidase-N (APN) and alkaline phosphatase (ALP) are important for Cry1A toxicity in some lepidopteran larvae, but the proteins that bind Cry2A in the midgut of target insects and their role in the Cry2A mechanism of action are still unclear. In this study, we found that heterologously expressed CAD, APN4 and ALP2 peptides from the midgut of Helicoverpa armigera could bind to the Cry2Aa toxin with a high affinity. Additionally, the efficiency of Cry2Aa insecticidal activity against H. armigera larvae was obviously reduced after the genes encoding these proteins were silenced with specific siRNAs: CAD- and ALP2-silenced larvae showed significantly similar reductions in mortality due to the Cry2Aa toxin (41.67% and 43.06%, respectively), whereas a larger reduction in mortality was observed in APN4-silenced larvae (61.11%) than in controls. These results suggest that CAD, APN4 and ALP2 are involved in the mechanism of action of Cry2Aa in H. armigera and may play important functional roles in the toxicity of the Cry2Aa toxin.
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Affiliation(s)
- Man Zhao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xiangdong Yuan
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Jizhen Wei
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Wanna Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Bingjie Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Myint Myint Khaing
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Gemei Liang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
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Recombinant Bacillus thuringiensis subsp. kurstaki HD73 strain that synthesizes Cry1Ac and chimeric ChiA74∆sp chitinase inclusions. Arch Microbiol 2017; 199:627-633. [DOI: 10.1007/s00203-017-1339-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 01/06/2017] [Accepted: 01/09/2017] [Indexed: 10/20/2022]
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