|
1
|
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.
Collapse
|
|
2
|
Li Y, Wang C, Ge L, Hu C, Wu G, Sun Y, Song L, Wu X, Pan A, Xu Q, Shi J, Liang J, Li P. Environmental Behaviors of Bacillus thuringiensis ( Bt) Insecticidal Proteins and Their Effects on Microbial Ecology. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11091212. [PMID: 35567212 PMCID: PMC9100956 DOI: 10.3390/plants11091212] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/27/2022] [Accepted: 04/28/2022] [Indexed: 05/12/2023]
Abstract
Bt proteins are crystal proteins produced by Bacillus thuringiensis (Bt) in the early stage of spore formation that exhibit highly specific insecticidal activities. The application of Bt proteins primarily includes Bt transgenic plants and Bt biopesticides. Transgenic crops with insect resistance (via Bt)/herbicide tolerance comprise the largest global area of agricultural planting. After artificial modification, Bt insecticidal proteins expressed from Bt can be released into soils through root exudates, pollen, and plant residues. In addition, the construction of Bt recombinant engineered strains through genetic engineering has become a major focus of Bt biopesticides, and the expressed Bt proteins will also remain in soil environments. Bt proteins expressed and released by Bt transgenic plants and Bt recombinant strains are structurally and functionally quite different from Bt prototoxins naturally expressed by B. thuringiensis in soils. The former can thus be regarded as an environmentally exogenous substance with insecticidal toxicity that may have potential ecological risks. Consequently, biosafety evaluations must be conducted before field tests and production of Bt plants or recombinant strains. This review summarizes the adsorption, retention, and degradation behavior of Bt insecticidal proteins in soils, in addition to their impacts on soil physical and chemical properties along with soil microbial diversity. The review provides a scientific framework for evaluating the environmental biosafety of Bt transgenic plants, Bt transgenic microorganisms, and their expression products. In addition, prospective research targets, research methods, and evaluation methods are highlighted based on current research of Bt proteins.
Collapse
Affiliation(s)
- Yujie Li
- College of Food Sciences and Technology, Shanghai Ocean University, Shanghai 201306, China;
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai 201106, China; (C.W.); (L.G.); (C.H.); (G.W.); (Y.S.); (L.S.); (X.W.); (A.P.)
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai 201106, China
| | - Cui Wang
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai 201106, China; (C.W.); (L.G.); (C.H.); (G.W.); (Y.S.); (L.S.); (X.W.); (A.P.)
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai 201106, China
| | - Lei Ge
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai 201106, China; (C.W.); (L.G.); (C.H.); (G.W.); (Y.S.); (L.S.); (X.W.); (A.P.)
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai 201106, China
| | - Cong Hu
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai 201106, China; (C.W.); (L.G.); (C.H.); (G.W.); (Y.S.); (L.S.); (X.W.); (A.P.)
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai 201106, China
| | - Guogan Wu
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai 201106, China; (C.W.); (L.G.); (C.H.); (G.W.); (Y.S.); (L.S.); (X.W.); (A.P.)
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai 201106, China
| | - Yu Sun
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai 201106, China; (C.W.); (L.G.); (C.H.); (G.W.); (Y.S.); (L.S.); (X.W.); (A.P.)
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai 201106, China
| | - Lili Song
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai 201106, China; (C.W.); (L.G.); (C.H.); (G.W.); (Y.S.); (L.S.); (X.W.); (A.P.)
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai 201106, China
| | - Xiao Wu
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai 201106, China; (C.W.); (L.G.); (C.H.); (G.W.); (Y.S.); (L.S.); (X.W.); (A.P.)
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai 201106, China
| | - Aihu Pan
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai 201106, China; (C.W.); (L.G.); (C.H.); (G.W.); (Y.S.); (L.S.); (X.W.); (A.P.)
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai 201106, China
| | - Qinqing Xu
- Shandong County Agricultural Technology Extension Center, Jinan 250003, China;
| | - Jialiang Shi
- Dezhou Academy of Agricultural Sciences, Dezhou 253000, China;
| | - Jingang Liang
- Development Center of Science and Technology, Ministry of Agriculture and Rural Affairs, Beijing 100176, China
- Correspondence: (J.L.); (P.L.)
| | - Peng Li
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai 201106, China; (C.W.); (L.G.); (C.H.); (G.W.); (Y.S.); (L.S.); (X.W.); (A.P.)
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Shanghai 201106, China
- Shanghai Co-Elite Agricultural Sci-Tech (Group) Co., Ltd., Shanghai 201106, China
- Correspondence: (J.L.); (P.L.)
| |
Collapse
|
|
3
|
Bacterial Toxins Active against Mosquitoes: Mode of Action and Resistance. Toxins (Basel) 2021; 13:toxins13080523. [PMID: 34437394 PMCID: PMC8402332 DOI: 10.3390/toxins13080523] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/18/2021] [Accepted: 06/19/2021] [Indexed: 12/25/2022] Open
Abstract
Larvicides based on the bacteria Bacillus thuringiensis svar. israelensis (Bti) and Lysinibacillus sphaericus are effective and environmentally safe compounds for the control of dipteran insects of medical importance. They produce crystals that display specific and potent insecticidal activity against larvae. Bti crystals are composed of multiple protoxins: three from the three-domain Cry type family, which bind to different cell receptors in the midgut, and one cytolytic (Cyt1Aa) protoxin that can insert itself into the cell membrane and act as surrogate receptor of the Cry toxins. Together, those toxins display a complex mode of action that shows a low risk of resistance selection. L. sphaericus crystals contain one major binary toxin that display an outstanding persistence in field conditions, which is superior to Bti. However, the action of the Bin toxin based on its interaction with a single receptor is vulnerable for resistance selection in insects. In this review we present the most recent data on the mode of action and synergism of these toxins, resistance issues, and examples of their use worldwide. Data reported in recent years improved our understanding of the mechanism of action of these toxins, showed that their combined use can enhance their activity and counteract resistance, and reinforced their relevance for mosquito control programs in the future years.
Collapse
|