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Bacillus thuringiensis: A Broader View of Its Biocidal Activity

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A special issue of Toxins (ISSN 2072-6651). This special issue belongs to the section "Bacterial Toxins".

Deadline for manuscript submissions: closed (31 December 2023) | Viewed by 32676

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Special Issue Editors

Dr. Leopoldo Palma

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Instituto de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, 46100 Burjassot, Spain
Interests: biological control of insect pests; crop protection; entomopathohenic bacteria; Bacillus thuriniensis; Xenorhabdus spp.; insecticidal proteins; pore forming toxins; insect resistance
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Dr. Diego Herman Sauka

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Instituto Nacional de Tecnología Agropecuaria (INTA), Instituto de Microbiología y Zoología Agrícola (IMYZA), Hurlingham, Buenos Aires B1686, Argentina
Interests: Bacillus thuringiensis; microbial entomopathogens; insecticidal proteins; insect pest control; bioinsecticides
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Jorge E. Ibarra

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Centro de Investigación y de Estudio Avanzados, Unidad Irapuato, Irapuato, Mexico
Interests: Bacillus thuringiensis; insect pathology; molecular biology of entomopathogens; bioinsecticides; transgenic plants

Special Issue Information

Dear Colleagues,

Bacillus thuringiensis (Bt) is the best-characterized Gram-positive entomopathogenic bacterium with many strains bearing plasmids containing a wide variety of insecticidal genes. This has bestowed Bt-based products as the most marketed microbial insecticides to date. The encoded insecticidal proteins include both crystal and vegetative insecticidal proteins highly toxic against a wide range of invertebrates, with several of them incorporated into crops conferring resistance to some of the most destructive insect pest species worldwide.

However, insects targeted by Bt crops have been subjected continuously to selective pressures and started showing resistance to some of the most used insecticidal proteins, which has promoted worldwide screening programs for strains harboring novel insecticidal proteins intended both to overcome insect resistance and to broaden host ranges.

This Special Issue of Toxins “Bacillus thuringiensis: A Broader View of Its Biocidal Activity” will address either the description of isolated Bt strains nor insecticidal proteins showing novel biocidal activities, which can be used not only for delaying/overcoming insect resistance but also for enlarging host spectrums.

Dr. Leopoldo Palma
Dr. Diego Sauka
Prof. Dr. Jorge E. Ibarra
Guest Editors

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Keywords

Bacillus thuringiensis
insecticidal proteins
crystal proteins
vegetative insecticidal proteins
invertebrate pests
biological control

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Published Papers (13 papers)

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Editorial

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3 pages, 210 KiB

Open AccessEditorial

Bacillus thuringiensis: A Broader View of Its Biocidal Activity

by Leopoldo Palma, Diego Herman Sauka and Jorge E. Ibarra

Toxins 2024, 16(3), 162; https://doi.org/10.3390/toxins16030162 - 20 Mar 2024

Viewed by 2516

Abstract

Bacillus thuringiensis (Bt) is a Gram-positive bacterium that forms spores and produces parasporal crystalline inclusions containing Cry and Cyt proteins [...] Full article

(This article belongs to the Special Issue Bacillus thuringiensis: A Broader View of Its Biocidal Activity)

Research

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13 pages, 2155 KiB

Open AccessArticle

N-Terminal α-Helices in Domain I of Bacillus thuringiensis Vip3Aa Play Crucial Roles in Disruption of Liposomal Membrane

by Ensi Shao, Hanye Huang, Jin Yuan, Yaqi Yan, Luru Ou, Xiankun Chen, Xiaohong Pan, Xiong Guan and Li Sha

Toxins 2024, 16(2), 88; https://doi.org/10.3390/toxins16020088 - 6 Feb 2024

Cited by 3 | Viewed by 1719

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. Full article

(This article belongs to the Special Issue Bacillus thuringiensis: A Broader View of Its Biocidal Activity)

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17 pages, 3493 KiB

Open AccessArticle

Domain III β4–β5 Loop and β14–β15 Loop of Bacillus thuringiensis Vip3Aa Are Involved in Receptor Binding and Toxicity

by Xiaoyue Hou, Mengjiao Li, Chengjuan Mao, Lei Jiang, Wen Zhang, Mengying Li, Xiaomeng Geng, Xin Li, Shu Liu, Guang Yang, Jing Zhou, Yaowei Fang and Jun Cai

Toxins 2024, 16(1), 23; https://doi.org/10.3390/toxins16010023 - 1 Jan 2024

Cited by 1 | Viewed by 1756

Abstract

Vip3Aa, secreted by Bacillus thuringiensis, is effective at controlling major agricultural pests such as Spodoptera frugiperda. However, to control Vip3Aa resistance evolved in the field by different lepidoptera species, an in–depth study of sequence––structure––activity relationships is necessary to design new Vip3Aa variants. In this study, the four specific loops (β4–β5 loop, β9–β10 loop, β12–β13 loop, and β14–β15 loop) in domain III were selected and four loop mutants were constructed by replacing all residues in each specific loop with alanine. We obtained soluble proteins for three of the loop mutants, excluding the β9–β10 loop. These loop mutants have been characterized by toxicity bioassays against S. frugiperda, proteolytic processing, and receptor binding. These results indicate that the β4–β5 loop and β14–β15 loop are involved in receptor binding and Vip3Aa toxicity. Based on this, we constructed numerous mutants and obtained three single mutants (Vip3Aa–S366T, Vip3Aa–S366L, and Vip3Aa–R501A) that exhibited significantly increased toxicity of 2.61–fold, 3.39–fold, and 2.51–fold, respectively. Compared to Vip3Aa, the receptor affinity of Vip3Aa–S366T and Vip3Aa–S366L was significantly enhanced. Furthermore, we also analyzed and aligned the three–dimensional structures of the mutants and Vip3Aa. In summary, these results indicate that the loops in domain III have the potential to be targeted to enhance the insecticidal toxicity of the Vip3Aa protein. Full article

(This article belongs to the Special Issue Bacillus thuringiensis: A Broader View of Its Biocidal Activity)

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9 pages, 2077 KiB

Open AccessCommunication

Bacillus thuringiensis Bt_UNVM-84, a Novel Strain Showing Insecticidal Activity against Anthonomus grandis Boheman (Coleoptera: Curculionidae)

by Diego Herman Sauka, Cecilia Peralta, Melisa Paula Pérez, Antonella Molla, Tadeo Fernandez-Göbel, Federico Ocampo and Leopoldo Palma

Toxins 2024, 16(1), 4; https://doi.org/10.3390/toxins16010004 - 20 Dec 2023

Cited by 4 | Viewed by 1973

Abstract

Bacillus thuringiensis is a Gram-positive bacterium known for its insecticidal proteins effective against various insect pests. However, limited strains and proteins target coleopteran pests like Anthonomous grandis Boheman, causing substantial economic losses in the cotton industry. This study focuses on characterizing a Bacillus sp. strain, isolated from Oncativo (Argentina), which exhibits ovoid to amorphous parasporal crystals and was designated Bt_UNVM-84. Its genome encodes genes for the production of two pairs of binary Vpb1/Vpa2 proteins and three Cry-like proteins showing similarity with different Cry8 proteins. Interestingly, this gene content was found to be conserved in a previously characterized Argentine isolate of B. thuringiensis designated INTA Fr7-4. SDS-PAGE analysis revealed a major band of 130 kDa that is proteolytically processed to an approximately 66-kDa protein fragment by trypsin. Bioassays performed with spore-crystal mixtures demonstrated an interesting insecticidal activity against the cotton boll weevil A. grandis neonate larvae, resulting in 91% mortality. Strain Bt_UNVM-84 is, therefore, an interesting candidate for the efficient biological control of this species, causing significant economic losses in the cotton industry in the Americas. Full article

(This article belongs to the Special Issue Bacillus thuringiensis: A Broader View of Its Biocidal Activity)

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13 pages, 989 KiB

Open AccessArticle

Field Evaluation of Cotton Expressing Mpp51Aa2 as a Management Tool for Cotton Fleahoppers, Pseudatomoscelis seriatus (Reuter)

by Brady P. Arthur, Charles P. Suh, Benjamin M. McKnight, Megha N. Parajulee, Fei Yang and David L. Kerns

Toxins 2023, 15(11), 644; https://doi.org/10.3390/toxins15110644 - 5 Nov 2023

Cited by 3 | Viewed by 2063

Abstract

The cotton fleahopper (Pseudatomoscelis seriatus Reuter) is considered a highly economically damaging pest of cotton (Gossypium hirsutum L.) in Texas and Oklahoma. Current control methods rely heavily on the use of foliar-applied chemical insecticides, but considering the cost of insecticides and the critical timeliness of applications, chemical control methods are often not optimized to reduce potential yield losses from this pest. The Bacillus thuringiensis (Bt) Mpp51Aa2 (formerly Cry51Aa2.834_16) protein has proven effective against thrips and plant bugs with piercing and sucking feeding behaviors, but the impact of this toxin on cotton fleahoppers has not been investigated. To evaluate the Mpp51Aa2 trait effectiveness towards the cotton fleahopper, field trials were conducted in 2019, 2020, and 2021, comparing a cotton cultivar containing the Mpp51Aa2 trait to a non-traited isoline cultivar under insecticide-treated and untreated conditions. Populations of cotton fleahopper nymphs and adults were estimated weekly by visually inspecting cotton terminals. Square retention was also assessed during the first week of bloom to provide some insight on how the Bt trait may influence yield. While cotton fleahopper population differences between the traited and non-traited plants were not consistently noted during the pre-bloom squaring period, there was a consistent increase in square retention in cotton expressing Mpp51Aa2 relative to non-traited cotton. Additionally, cotton expressing Mpp51Aa2 offered similar square protection relative to non-traited cotton treated with insecticides for the cotton fleahopper. These findings indicate that the Mpp51Aa2 protein should provide benefits of delayed nymphal growth, population suppression, and increased square retention. Full article

(This article belongs to the Special Issue Bacillus thuringiensis: A Broader View of Its Biocidal Activity)

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12 pages, 746 KiB

Open AccessArticle

Baseline Susceptibility of the Field Populations of Ostrinia furnacalis in Indonesia to the Proteins Cry1A.105 and Cry2Ab2 of Bacillus thuringiensis

by Y. Andi Trisyono, Valentina E. F. Aryuwandari, Teguh Rahayu, Samuel Martinelli, Graham P. Head, Srinivas Parimi and Luis R. Camacho

Toxins 2023, 15(10), 602; https://doi.org/10.3390/toxins15100602 - 7 Oct 2023

Cited by 1 | Viewed by 1776

Abstract

Genetically modified MON 89034 corn (Zea mays L.) expressing Bacillus thuringiensis (Bt) insecticidal proteins, viz. Cry1A.105 and Cry2Ab2, is a biotechnological option being considered for the management of the major corn pest in Indonesia, the Asian corn borer (Ostrinia furnacalis (Guenée) (Lepidoptera: Crambidae)). As a part of a proactive resistance-management program for MON 89034 corn in Indonesia, we assessed the baseline susceptibility of field-collected populations of O. furnacalis to Cry1A.105 and Cry2Ab2 proteins. Dose–response bioassays using the diet-dipping method indicated that the lethal concentration (LC₅₀) values of Cry1A.105 and Cry2Ab2 in 24 different field populations of O. furnacalis ranged from 0.006 to 0.401 µg/mL and from 0.044 to 4.490 µg/mL, respectively, while the LC₉₅ values ranged from 0.069 to 15.233 µg/mL for Cry1A.105 and from 3.320 to 277.584 µg/mL for Cry2Ab2. The relative resistance ratios comparing the most tolerant field populations and an unselected laboratory population were 6.0 for Cry1A.105 and 2.0 for Cry2Ab2 based on their LC₅₀ values. Some field populations were more susceptible to both proteins than the unselected laboratory population. The LC₉₉ and its 95% fiducial limits across the field populations were calculated and proposed as candidate diagnostic concentrations. These data provide a basis for resistance monitoring in Bt Corn and further support building resistance-management strategies in Indonesia. Full article

(This article belongs to the Special Issue Bacillus thuringiensis: A Broader View of Its Biocidal Activity)

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12 pages, 2310 KiB

Open AccessArticle

Analysis of Synergism between Extracellular Polysaccharide from Bacillus thuringensis subsp. kurstaki HD270 and Insecticidal Proteins

by Bai Xue, Meiling Wang, Zeyu Wang, Changlong Shu, Lili Geng and Jie Zhang

Toxins 2023, 15(10), 590; https://doi.org/10.3390/toxins15100590 - 28 Sep 2023

Cited by 2 | Viewed by 1462

Abstract

Bacillus thuringiensis (Bt) is the most widely used biopesticide worldwide and can produce several insecticidal crystal proteins and vegetative insecticidal proteins (Vips) at different growth stages. In our previous study, extracellular polysaccharides (EPSs) of Bt strain HD270 were found to enhance the insecticidal activity of Cry1Ac protoxin against Plutella xylostella (L.) and promote the binding of Cry1Ac to the intestinal brush border membrane vesicles (BBMVs). Whether the synergistic activity of Bt EPSs is common to other Cry1-type or Vip proteins is unclear, as is the potential synergistic mechanism. In this study, crude EPS-HD270 was found to increase the toxicity of Cry1-type toxins and Vip3Aa11 against different lepidopteran pests by approximately 2-fold. The purified EPS-HD270 also possessed synergistic activity against the toxicity of Cry1Ac and Vip3Aa11 against Spodoptera frugiperda (J.E. Smith) and Helicoverpa armigera (Hübner). Furthermore, we found that EPS-HD270 had a strong binding ability with Vip3Aa11 and promoted the binding of Vip3Aa11 to the BBMVs of H. armigera and S. frugiperda. Bt EPS-HD270 also protected Vip3Aa11 from proteolytic processing in larval midgut juice. Bt EPSs had universal synergistic effects on Cry1-type or Vip toxins against S. frugiperda and H. armigera. Bt EPS-HD270 exhibited synergistic activity with Vip3Aa through promotion of binding to BBMVs and protection from digestion by midgut protease. The results indicated that synergistic activity with Bt toxins was an important function of Bt EPSs, which was very different from other Bacillus spp. Full article

(This article belongs to the Special Issue Bacillus thuringiensis: A Broader View of Its Biocidal Activity)

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11 pages, 2989 KiB

Open AccessCommunication

Processing Properties and Potency of Bacillus thuringiensis Cry Toxins in the Rice Leaffolder Cnaphalocrocis medinalis (Guenée)

by Yajun Yang, Zhihong Wu, Xiaochan He, Hongxing Xu and Zhongxian Lu

Toxins 2023, 15(4), 275; https://doi.org/10.3390/toxins15040275 - 6 Apr 2023

Viewed by 1766

Abstract

Different Cry toxins derived from Bacillus thuringiensis (Bt) possess different insecticidal spectra, whereas insects show variations in their susceptibilities to different Cry toxins. Degradation of Cry toxins by insect midgut extracts was involved in the action of toxins. In this study, we explored the processing patterns of different Cry toxins in Cnaphalocrocis medinalis (Lepidoptera: Crambidae) midgut extracts and evaluated the impact of Cry toxins degradation on their potency against C. medinalis to better understand the function of midgut extracts in the action of different Cry toxins. The results indicated that Cry1Ac, Cry1Aa, and Cry1C toxins could be degraded by C. medinalis midgut extracts, and degradation of Cry toxins by midgut extracts differed among time or concentration effects. Bioassays demonstrated that the toxicity of Cry1Ac, Cry1Aa, and Cry1C toxins decreased after digestion by midgut extracts of C. medinalis. Our findings in this study suggested that midgut extracts play an important role in the action of Cry toxins against C. medinalis, and the degradation of Cry toxins by C. medinalis midgut extracts could reduce their toxicities to C. medinalis. They will provide insights into the action of Cry toxins and the application of Cry toxins in C. medinalis management in paddy fields. Full article

(This article belongs to the Special Issue Bacillus thuringiensis: A Broader View of Its Biocidal Activity)

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17 pages, 2288 KiB

Open AccessArticle

Bacillus thuringiensis Cyt Proteins as Enablers of Activity of Cry and Tpp Toxins against Aedes albopictus

by Liliana Lai, Maite Villanueva, Ane Muruzabal-Galarza, Ana Beatriz Fernández, Argine Unzue, Alejandro Toledo-Arana, Primitivo Caballero and Carlos J. Caballero

Toxins 2023, 15(3), 211; https://doi.org/10.3390/toxins15030211 - 10 Mar 2023

Cited by 7 | Viewed by 3580

Abstract

Aedes albopictus is a species of mosquito, originally from Southeast Asia, that belongs to the Culicidae family and the Dipteran insect order. The distribution of this vector has rapidly changed over the past decade, making most of the temperate territories in the world vulnerable to important human vector-borne diseases such as dengue, yellow fever, zika or chikungunya. Bacillus thuringiensis var. israeliensis (Bti)-based insecticides represent a realistic alternative to the most common synthetic insecticides for the control of mosquito larvae. However, several studies have revealed emerging resistances to the major Bti Crystal proteins such as Cry4Aa, Cry4Ba and Cry11Aa, making the finding of new toxins necessary to diminish the exposure to the same toxicity factors overtime. Here, we characterized the individual activity of Cyt1Aa, Cry4Aa, Cry4Ba and Cry11Aa against A. albopictus and found a new protein, Cyt1A-like, that increases the activity of Cry11Aa more than 20-fold. Additionally, we demonstrated that Cyt1A-like facilitates the activity three new Bti toxins: Cry53-like, Cry56A-like and Tpp36-like. All in all, these results provide alternatives to the currently available Bti products for the control of mosquito populations and position Cyt proteins as enablers of activity for otherwise non-active crystal proteins. Full article

(This article belongs to the Special Issue Bacillus thuringiensis: A Broader View of Its Biocidal Activity)

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8 pages, 720 KiB

Open AccessCommunication

Mpp23Aa/Xpp37Aa Insecticidal Proteins from Bacillus thuringiensis (Bacillales: Bacillaceae) Are Highly Toxic to Anthonomus grandis (Coleoptera: Curculionidae) Larvae

by Jéssica A. de Oliveira, Bárbara F. Negri, Patricia Hernández-Martínez, Marcos F. Basso and Baltasar Escriche

Toxins 2023, 15(1), 55; https://doi.org/10.3390/toxins15010055 - 8 Jan 2023

Cited by 5 | Viewed by 2379

Abstract

The beetle Anthonomus grandis Boheman, 1843, is the main cotton pest, causing enormous losses in cotton. The breeding of genetically modified plants with A. grandis resistance is seen as an important control strategy. However, the identification of molecules with high toxicity to this insect remains a challenge. The susceptibility of A. grandis larvae to proteins (Cry1Ba, Cry7Ab, and Mpp23Aa/Xpp37Aa) from Bacillus thuringiensis Berliner, 1915, with toxicity reported against Coleopteran, has been evaluated. The ingestion of different protein concentrations (which were incorporated into an artificial diet) by the larvae was tested in the laboratory, and mortality was evaluated after one week. All Cry proteins tested exhibited higher toxicity than that the untreated artificial diet. These Cry proteins showed similar results to the control Cry1Ac, with low toxicity to A. grandis, since it killed less than 50% of larvae, even at the highest concentration applied (100 μg·g⁻¹). Mpp/Xpp proteins provided the highest toxicity with a 0.18 μg·g⁻¹ value for the 50% lethal concentration. Importantly, this parameter is the lowest ever reported for this insect species tested with B. thuringiensis proteins. This result highlights the potential of Mpp23Aa/Xpp37Aa for the development of a biotechnological tool aiming at the field control of A. grandis. Full article

(This article belongs to the Special Issue Bacillus thuringiensis: A Broader View of Its Biocidal Activity)

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16 pages, 2345 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

The Crystal Structure of Bacillus thuringiensis Tpp80Aa1 and Its Interaction with Galactose-Containing Glycolipids

by Hannah L. Best, Lainey J. Williamson, Magdalena Lipka-Lloyd, Helen Waller-Evans, Emyr Lloyd-Evans, Pierre J. Rizkallah and Colin Berry

Toxins 2022, 14(12), 863; https://doi.org/10.3390/toxins14120863 - 8 Dec 2022

Cited by 7 | Viewed by 3225

Abstract

Tpp80Aa1 from Bacillus thuringiensis is a Toxin_10 family protein (Tpp) with reported action against Culex mosquitoes. Here, we demonstrate an expanded target range, showing Tpp80Aa1 is also active against the larvae of Anopheles gambiae and Aedes aegypti mosquitoes. We report the first crystal structure of Tpp80Aa1 at a resolution of 1.8 Å, which shows Tpp80Aa1 consists of two domains: an N-terminal β-trefoil domain resembling a ricin B lectin and a C-terminal putative pore-forming domain sharing structural similarity with the aerolysin family. Similar to other Tpp family members, we observe Tpp80Aa1 binds to the mosquito midgut, specifically the posterior midgut and the gastric caecum. We also identify that Tpp80Aa1 can interact with galactose-containing glycolipids and galactose, and this interaction is critical for exerting full insecticidal action against mosquito target cell lines. Full article

(This article belongs to the Special Issue Bacillus thuringiensis: A Broader View of Its Biocidal Activity)

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12 pages, 5533 KiB

Open AccessArticle

Insights from the Structure of an Active Form of Bacillus thuringiensis Cry5B

by Jiaxin Li, Lin Wang, Masayo Kotaka, Marianne M. Lee and Michael K. Chan

Toxins 2022, 14(12), 823; https://doi.org/10.3390/toxins14120823 - 23 Nov 2022

Cited by 3 | Viewed by 2176

Abstract

The crystal protein Cry5B, a pore-forming protein produced by the soil bacterium Bacillus thuringiensis, has been demonstrated to have excellent anthelmintic activity. While a previous structure of the three-domain core region of Cry5B(112–698) had been reported, this structure lacked a key N-terminal extension critical to function. Here we report the structure of Cry5B(27–698) containing this N-terminal extension. This new structure adopts a distinct quaternary structure compared to the previous Cry5B(112–698) structure, and also exhibits a change in the conformation of residues 112–140 involved in linking the N-terminal extension to the three-domain core by forming a random coil and an extended α-helix. A role for the N-terminal extension is suggested based on a computational model of the tetramer with the conformation of residues 112–140 in its alternate α-helix conformation. Finally, based on the Cry5B(27–698) structure, site-directed mutagenesis studies were performed on Tyr495, which revealed that having an aromatic group or bulky group at this residue 495 is important for Cry5B toxicity. Full article

(This article belongs to the Special Issue Bacillus thuringiensis: A Broader View of Its Biocidal Activity)

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21 pages, 3252 KiB

Open AccessArticle

Multifunctional Properties of a Bacillus thuringiensis Strain (BST-122): Beyond the Parasporal Crystal

by Argine Unzue, Carlos J. Caballero, Maite Villanueva, Ana Beatriz Fernández and Primitivo Caballero

Toxins 2022, 14(11), 768; https://doi.org/10.3390/toxins14110768 - 7 Nov 2022

Cited by 3 | Viewed by 3896

Abstract

Chemical products still represent the most common form of controlling crop pests and diseases. However, their extensive use has led to the selection of resistances. This makes the finding of new solutions paramount to countering the economic losses that pests and diseases represent in modern agriculture. Bacillus thuringiensis (Bt) is one of the most reliable alternatives to chemical-based solutions. In this study, we aimed to further expand the global applicability of Bt strains beyond their spores and crystals. To this end, we selected a new Bt strain (BST-122) with relevant toxicity factors and tested its activity against species belonging to different phyla. The spore and crystal mixture showed toxicity to coleopterans. Additionally, a novel Cry5-like protein proved active against the two-spotted spider mite. In vivo and plant assays revealed significant control of the parasitic nematode, Meloidogyne incognita. Surprisingly, our data indicated that the nematocidal determinants may be secreted. When evaluated against phytopathogenic fungi, the strain seemed to decelerate their growth. Overall, our research has highlighted the potential of Bt strains, expanding their use beyond the confinements of spores and crystals. However, further studies are required to pinpoint the factors responsible for the wide host range properties of the BST-122 strain. Full article

(This article belongs to the Special Issue Bacillus thuringiensis: A Broader View of Its Biocidal Activity)

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