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Cong R, Hou JT, Yamamoto T. High-throughput screening for novel Bacillus thuringiensis insecticidal proteins revealed evidence that the bacterium exchanges Domain III to enhance its insecticidal activity. JOURNAL OF PESTICIDE SCIENCE 2024; 49:148-158. [PMID: 39398507 PMCID: PMC11464270 DOI: 10.1584/jpestics.d24-011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 05/14/2024] [Indexed: 10/15/2024]
Abstract
Approximately 3000 Bacillus thuringiensis (Bt) isolates were screened to discover novel three-domain (3D) Cry proteins active against Helicoverpa zea (corn earworm). From 400 active isolates found during the primary screening, Cry1Ac and Cry2A, which are known to be active against H. zea, were removed using multiplex-primer PCR and high-throughput column chromatography. This process reduced the number of active cultures to 48. DNA segments encoding Domain III of these 48 cultures were amplified by PCR and sequenced. Sequencing revealed two novel Cry1B-type Domain IIIs. Further sequencing of the flanking regions of these domains revealed that one was part of Cry1Bj (GenBank: KT952325). However, the other Domain III lacked Domains I and II. Instead, this Domain III was associated with two open reading frames, ORF1 and ORF2. ORF1 was identified as an ATP-binding protein, and ORF2 as an ATPase, suggesting that Bt exchanges Domain III among homologous Cry proteins.
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Qiao J, Borriss R, Sun K, Zhang R, Chen X, Liu Y, Liu Y. Research advances in the identification of regulatory mechanisms of surfactin production by Bacillus: a review. Microb Cell Fact 2024; 23:100. [PMID: 38566071 PMCID: PMC10988940 DOI: 10.1186/s12934-024-02372-7] [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: 11/16/2023] [Accepted: 03/18/2024] [Indexed: 04/04/2024] Open
Abstract
Surfactin is a cyclic hexalipopeptide compound, nonribosomal synthesized by representatives of the Bacillus subtilis species complex which includes B. subtilis group and its closely related species, such as B. subtilis subsp subtilis, B. subtilis subsp spizizenii, B. subtilis subsp inaquosorum, B. atrophaeus, B. amyloliquefaciens, B. velezensis (Steinke mSystems 6: e00057, 2021) It functions as a biosurfactant and signaling molecule and has antibacterial, antiviral, antitumor, and plant disease resistance properties. The Bacillus lipopeptides play an important role in agriculture, oil recovery, cosmetics, food processing and pharmaceuticals, but the natural yield of surfactin synthesized by Bacillus is low. This paper reviews the regulatory pathways and mechanisms that affect surfactin synthesis and release, highlighting the regulatory genes involved in the transcription of the srfAA-AD operon. The several ways to enhance surfactin production, such as governing expression of the genes involved in synthesis and regulation of surfactin synthesis and transport, removal of competitive pathways, optimization of media, and fermentation conditions were commented. This review will provide a theoretical platform for the systematic genetic modification of high-yielding strains of surfactin.
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Affiliation(s)
- Junqing Qiao
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, Jiangsu, China
| | - Rainer Borriss
- Institute of Biology, Humboldt University Berlin, Berlin, Germany.
| | - Kai Sun
- College of Plant Protection, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Rongsheng Zhang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, Jiangsu, China
| | - Xijun Chen
- College of Plant Protection, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Youzhou Liu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, Jiangsu, China.
| | - Yongfeng Liu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, Jiangsu, China.
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Miranda LS, Rudd SR, Mena O, Hudspeth PE, Barboza-Corona JE, Park HW, Bideshi DK. The Perpetual Vector Mosquito Threat and Its Eco-Friendly Nemeses. BIOLOGY 2024; 13:182. [PMID: 38534451 DOI: 10.3390/biology13030182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Revised: 03/06/2024] [Accepted: 03/08/2024] [Indexed: 03/28/2024]
Abstract
Mosquitoes are the most notorious arthropod vectors of viral and parasitic diseases for which approximately half the world's population, ~4,000,000,000, is at risk. Integrated pest management programs (IPMPs) have achieved some success in mitigating the regional transmission and persistence of these diseases. However, as many vector-borne diseases remain pervasive, it is obvious that IPMP successes have not been absolute in eradicating the threat imposed by mosquitoes. Moreover, the expanding mosquito geographic ranges caused by factors related to climate change and globalization (travel, trade, and migration), and the evolution of resistance to synthetic pesticides, present ongoing challenges to reducing or eliminating the local and global burden of these diseases, especially in economically and medically disadvantaged societies. Abatement strategies include the control of vector populations with synthetic pesticides and eco-friendly technologies. These "green" technologies include SIT, IIT, RIDL, CRISPR/Cas9 gene drive, and biological control that specifically targets the aquatic larval stages of mosquitoes. Regarding the latter, the most effective continues to be the widespread use of Lysinibacillus sphaericus (Ls) and Bacillus thuringiensis subsp. israelensis (Bti). Here, we present a review of the health issues elicited by vector mosquitoes, control strategies, and lastly, focus on the biology of Ls and Bti, with an emphasis on the latter, to which no resistance has been observed in the field.
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Affiliation(s)
- Leticia Silva Miranda
- Graduate Program in Biomedical Sciences, Department of Biological Sciences, California Baptist University, Riverside, CA 92504, USA
| | - Sarah Renee Rudd
- Graduate Program in Biomedical Sciences, Department of Biological Sciences, California Baptist University, Riverside, CA 92504, USA
- Integrated Biomedical Graduate Studies, and School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
| | - Oscar Mena
- Undergraduate Program in Biomedical Sciences, Department of Biological Sciences, California Baptist University, Riverside, CA 92504, USA
| | - Piper Eden Hudspeth
- Undergraduate Program in Biomedical Sciences, Department of Biological Sciences, California Baptist University, Riverside, CA 92504, USA
| | - José E Barboza-Corona
- Departmento de Alimentos, Posgrado en Biociencias, Universidad de Guanajuato Campus Irapuato-Salamanca, Irapuato 36500, Guanajuato, Mexico
| | - Hyun-Woo Park
- Graduate Program in Biomedical Sciences, Department of Biological Sciences, California Baptist University, Riverside, CA 92504, USA
- Undergraduate Program in Biomedical Sciences, Department of Biological Sciences, California Baptist University, Riverside, CA 92504, USA
| | - Dennis Ken Bideshi
- Graduate Program in Biomedical Sciences, Department of Biological Sciences, California Baptist University, Riverside, CA 92504, USA
- Undergraduate Program in Biomedical Sciences, Department of Biological Sciences, California Baptist University, Riverside, CA 92504, USA
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Morwool P, Dimitriu T, Crickmore N, Raymond B. Group Selection as a Basis for Screening Mutagenized Libraries of Public Goods (Bacillus thuringiensis Cry Toxins). Appl Environ Microbiol 2023; 89:e0051223. [PMID: 37358425 PMCID: PMC10370297 DOI: 10.1128/aem.00512-23] [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: 03/28/2023] [Accepted: 05/26/2023] [Indexed: 06/27/2023] Open
Abstract
The pesticidal toxins of Bacillus thuringiensis (Bt) supply the active proteins for genetically modified insect-resistant crops. There is therefore keen interest in finding new toxins, or improving known toxins, in order to increase the mortality of various targets. The production and screening of large libraries of mutagenized toxins are among the means of identifying improved toxins. Since Cry toxins are public goods, and do not confer advantages to producers in competition, conventional directed evolution approaches cannot be used here. Instead, thousands of individual mutants have to be sequenced and assayed individually, a costly and time-consuming process. In this study, we tested a group selection-based approach that could be used to screen an uncharacterized pool of Cry toxin mutants. This involved selecting for infectivity between subpopulations of Bt clones within metapopulations of infected insects in three rounds of passage. We also tested whether additional mutagenesis from exposure to ethyl methanesulfonate could increase infectivity or supply additional Cry toxin diversity during passage. Sequencing of pools of mutants at the end of selection showed that we could effectively screen out Cry toxin variants that had reduced toxicity with our group selection approach. The addition of extra mutagenesis during passage decreased the efficiency of selection for infectivity and did not produce any additional novel toxin diversity. Toxins with loss-of-function mutations tend to dominate mutagenized libraries, and so a process for screening out these mutants without time-consuming sequencing and characterization steps could be beneficial when applied to larger libraries. IMPORTANCE Insecticidal toxins from the bacterium Bacillus thuringiensis are widely exploited in genetically modified plants. This application creates a demand for novel insecticidal toxins that can be used to better manage resistant pests or control new or recalcitrant target species. An important means of producing novel toxins is via high-throughput mutagenesis and screening of existing toxins, a lengthy and resource-intensive process. This study describes the development and testing of an efficient means of screening a test library of mutagenized insecticidal toxins. Here, we showed that it is possible to screen out loss-of-function mutations with low infectivity within a pool without the need to characterize and sequence each mutant individually. This has the potential to improve the efficiency of processes used to identify novel proteins.
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Affiliation(s)
| | | | - Neil Crickmore
- Department of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Ben Raymond
- University of Exeter, Penryn, United Kingdom
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dos Santos IB, Paula-Moraes SV, Beuzelin JM, Hahn DA, Perera OP, Fraisse C. Factors Affecting Population Dynamics of Helicoverpa zea (Lepidoptera: Noctuidae) in a Mixed Landscape with Bt Cotton and Peanut. INSECTS 2023; 14:395. [PMID: 37103210 PMCID: PMC10142863 DOI: 10.3390/insects14040395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/14/2023] [Accepted: 04/15/2023] [Indexed: 06/19/2023]
Abstract
In North America, weather and host-plant abundance drive the population dynamics of the migratory pest Helicoverpa zea. The objectives of this study were to (i) estimate monthly abundance of H. zea moths in Bt cotton and peanut fields, (ii) document the effects of weather on H. zea trap catches, and (iii) determine larval hosts supporting H. zea populations from 2017 to 2019. Year-round trapping of H. zea moths was conducted in 16 commercial fields in two regions of the Florida Panhandle using delta traps. H. zea moth catches were associated with temperature, rainfall, and relative humidity. Larval hosts were determined by isotopic carbon analysis. Our results showed year-round H. zea flights in both regions across two years, with the highest and lowest moth catches occurring from July to September and November to March, respectively. There was no difference in catches between traps set on Bt cotton and peanut. In the Santa Rosa/Escambia counties, weather explained 59% of the variance in H. zea catches, with significant effects of temperature, relative humidity, and rainfall. In Jackson County, weather explained 38% of H. zea catches, with significant effects of temperature and relative humidity. Carbon isotopic data showed that feeding on C3 plants, including Bt cotton, occurred over most of the year, although feeding on C4 hosts, including Bt corn, occurred during the summer months. Hence overwintering and resident populations of H. zea in the Florida Panhandle may be continually exposed to Bt crops, increasing the risk for the evolution of resistance.
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Affiliation(s)
- Izailda Barbosa dos Santos
- West Florida Research and Education Center, Department of Entomology and Nematology, University of Florida, Jay, FL 32565, USA
| | - Silvana V. Paula-Moraes
- West Florida Research and Education Center, Department of Entomology and Nematology, University of Florida, Jay, FL 32565, USA
| | - Julien M. Beuzelin
- Everglades Research and Education Center, Department of Entomology and Nematology, University of Florida, 3200 East Palm Beach Road, Belle Glade, FL 33430, USA
| | - Daniel A. Hahn
- Department of Entomology and Nematology, University of Florida, 1881 Natural Area Drive, Gainesville, FL 32611, USA
| | | | - Clyde Fraisse
- Department of Agricultural and Biological Engineering, University of Florida, 271 Frazier Rogers Hall, Gainesville, FL 32611, USA
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