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Bacillus thuringiensis receptors

Kavita Nair, Ahmad Iskandarani, Roda Al-Thani, Ramzi Mohammad, Samir Jaoua
Cyt1A protein is a cytolytic protein encoded by the cyt gene of Bacillus thuringiensis subsp. israelensis (Bti) as part of the parasporal crystal proteins produced during the sporulation. Cyt1A protein is unique compared to the other endotoxins present in these parasporal crystals. Unlike δ-endotoxins, Cyt1A protein does not require receptors to bind to the target cell and activate the toxicity. It has the ability to affect a broad range of cell types and organisms, due to this characteristic. Cyt1A has been recognized to not only target the insect cells directly, but also recruit other endotoxins by acting as receptors...
March 16, 2018: Toxins
Junxiang Wang, Guifang Lin, Khadija Batool, Shuaiqi Zhang, Mingfeng Chen, Jin Xu, Juan Wu, Liang Jin, Ivan Gelbic, Lei Xu, Lingling Zhang, Xiong Guan
Ectropis oblique Prout (Lepidoptera: Geometridae) is one of the main pests that damages the tea crop in Southeast Asia. To understand the molecular mechanisms of its feeding biology, transcriptomes of the alimentary tract (AT) and of the body minus the AT of E. oblique were successfully sequenced and analyzed in this study. A total of 36,950 unigenes from de novo sequences were assembled. After analysis using six annotation databases (e.g., Gene Ontology, Kyoto Encyclopedia of Genes and Genome, and NCBI nr), a series of putative genes were found for this insect species that were related to digestion, detoxification, the immune system, and Bacillus thuringiensis (Bt) receptors...
March 12, 2018: Journal of Economic Entomology
Donghai Peng, Danfeng Wan, Chunsheng Cheng, Xiaobo Ye, Ming Sun
Parasitic nematodes of animals and plants cause worldwide devastating impacts on people's lives and agricultural crops. The crystal protein Cry5B produced by Bacillus thuringiensis has efficient and specific activity against a wide range of nematodes. However, the action mode of this toxin has not yet been thoroughly determined. Here, a nematode-specific cadherin CDH-8 was demonstrated to be a receptor for Cry5B toxin by using Caenorhabditis elegans as a model, providing evidence that the cadherin mutant worm cdh-8(RB815) possesses significant resistance to Cry5B, and the CDH-8 fragments bind specifically to Cry5B...
March 3, 2018: Applied Microbiology and Biotechnology
Hanen Boukedi, Slim Tounsi, Lobna Abdelkefi-Mesrati
The carob moth, Ectomyelois ceratoniae, is an important agricultural pest that is susceptible to the Vip3(459) protein. The insecticidal activity, evaluated against this lepidopteran pest, displayed an LC 50 value of about 28 ng/cm 2 .The investigation of the mode of action of this B. thuringiensis protein demonstrated that the active form of this toxin bound to putative receptors in the BBMV of E. ceratoniae. Ligand blotting experiment proved that Vip3(459) specifically bound to two proteins of about 53 and 57 kDa, located on the midgut...
February 12, 2018: Acta Tropica
Haruka Endo, Satomi Adegawa, Shingo Kikuta, Ryoichi Sato
The cadherin-like protein in lepidopteran insects, known as a receptor for Bacillus thuringiensis Cry1A toxins, is a single-pass membrane protein that can be divided into extracellular and intracellular regions. The extracellular region is important for toxin binding and oligomerization, whereas the role of the intracellular region during Cry1A intoxication is unclear. In the present study, we generated a deletion mutant of Bombyx mori cadherin-like protein (BtR175) that lacked the intracellular region to investigate its role in mediating Cry1A toxicity...
February 6, 2018: Insect Biochemistry and Molecular Biology
Ensi Shao, Li Lin, Sijun Liu, Jiao Zhang, Xuelin Chen, Li Sha, Zhipeng Huang, Biwang Huang, Xiong Guan
The brown planthopper (BPH) Nilaparvata lugens is one of the most destructive insect pests in the rice fields of Asia. Like other hemipteran insects, BPH is not susceptible to Cry toxins of Bacillus thuringiensis (Bt) or transgenic rice carrying Bt cry genes. Lack of Cry receptors in the midgut is one of the main reasons that BPH is not susceptible to the Cry toxins. The main Cry-binding proteins (CBPs) of the susceptible insects are cadherin, aminopeptidase N (APN), and alkaline phosphatase (ALP). In this study, we analyzed and validated de novo assembled transcripts from transcriptome sequencing data of BPH to identify and characterize homologs of cadherin, APN, and ALP...
February 5, 2018: Journal of Insect Science
Xiaodi Li, Feng Zhao, Xianfeng Qiu, Xiaomeng Ren, Xiangtao Mo, Xuezhi Ding, Liqiu Xia, Yunjun Sun
The new dual model for Bacillus thuringiensis insecticidal mechanism proposed that Cry1A protoxins without proteolytic activation could bind to insect midgut receptors to exert toxicity. To evaluate insecticidal potency of Cry1Ac protoxin at precluding interference of midgut proteases, the cytotoxicity of Cry1Ac protoxin against midgut cell line CF-203 derived from Choristoneura fumiferana was analyzed. It was revealed that Cry1Ac protoxin was toxic to CF-203 cells and there existed certain differences in the cytological changes when treated with protoxin and toxin...
January 30, 2018: Journal of Invertebrate Pathology
Lian Xu, Zhi-Zhen Pan, Jing Zhang, Li-Yang Niu, Jie Li, Zheng Chen, Bo Liu, Yu-Jing Zhu, Qing-Xi Chen
Cry2Ab, a pore-forming toxin (PFT) derived from Bacillus thuringiensis (Bt), is widely used as a bio-insecticides to control lepidopteran pests around the world. A previous study revealed that proteolytic activation of Cry2Ab by Plutella xylostella midgut juice (PxMJ) was essential for its insecticidal activity against P. xylostella, although the exact molecular mechanism remained unknown. Here we demonstrated for the first time that proteolysis of Cry2Ab uncovered an active region (the helices α4-α5 in Domain I), which was required for the mode of action of Cry2Ab...
January 30, 2018: Cellular Microbiology
Hanen Boukedi, Saoussen Ben Khedher, Lobna Abdelkefi-Mesrat, Jeroen Van Rie, Slim Tounsi
The cotton leaf worm Spodoptera littoralis is known for causing serious damages to various crops. In this study, the susceptibility/tolerance of this larvae to four Vip3A (Vip3Aa, Vip3Ae, Vip3Ad and Vip3Af) toxins was investigated. UnlikeVip3Ad which showed no activity to S. littoralis, Vip3Aa, Vip3Ae and Vip3Af exhibited high toxicity to this larva with LC50 of 228.42 ng/cm2, 65.71 ng/cm2, and 388.90 ng/cm2, respectively. Activation of the 90 kDa Vip3A proteins by S. littoralis larvae juice generated four major bands of sizes 62, 45, 33 and 22 kDa...
January 26, 2018: Journal of Invertebrate Pathology
Dalel BenFarhat-Touzri, Fatma Driss, Sonia Jemli, Slim Tounsi
Bacillus thuringiensis subsp. aizawai strain HD133, known by its effectiveness against Spodoptera species, produces bipyramidal crystals encompassing the insecticidal proteins Cry1Ab, Cry1Ca and Cry1D-133 in the proportions 60:37:3, respectively. In this study, we dealt with the relevance of the low rate of Cry1D-133. The cry1D-133 gene from HD133 was cloned and sequenced. Both nucleotide and amino acid sequence similarity analyses with the cry1D genes available in the GenBank database revealed that cry1D-133 is a new variant of cry1Da-type genes with 99% identity with cry1Da1...
January 20, 2018: International Journal of Biological Macromolecules
Xiaodan Hu, Xiao Zhang, Jianfeng Zhong, Yuan Liu, Cunzheng Zhang, Yajing Xie, Manman Lin, Chongxin Xu, Lina Lu, Qing Zhu, Xianjin Liu
Cadherin-like protein has been identified as the primary Bacillus thuringiensis (Bt) Cry toxin receptor in Lepidoptera pests and plays a key role in Cry toxin insecticidal. In this study, we successfully expressed the putative Cry1Ac toxin-binding region (CR7-CR11) of Plutella xylostella cadherin-like in Escherichia coli BL21 (DE3). The expressed CR7-CR11 fragment showed binding ability to Cry1Ac toxin under denaturing (Ligand blot) and non-denaturing (ELISA) conditions. The three-dimensional structure of CR7-CR11 was constructed by homology modeling...
January 2, 2018: International Journal of Biological Macromolecules
Y-A Tan, X-D Zhao, Y Sun, D-J Hao, J Zhao, Y-P Jiang, L-X Bai, L-B Xiao
Apolygus lucorum is the predominant pest of Bacillus thuringiensis (Bt) cotton in China. 20-hydroxyecdysone (20E) plays a key role in the reproduction of this insect. To better understand the mechanism underlying 20E-regulated reproduction, the nuclear hormone receptor E75 isoform-A of Ap. lucorum (Al-E75A) was cloned and its expression analysed. A 2241-bp sequence of Al-E75A cDNA encoded an open reading frame of a polypeptide with a predicted molecular mass of 69.04 kDa. Al-E75A mRNA was detected in female adult stages of Ap...
November 29, 2017: Insect Molecular Biology
Shiho Tanaka, Haruka Endo, Satomi Adegawa, Ami Iizuka, Kazuhiro Imamura, Shingo Kikuta, Ryoichi Sato
Because Bombyx mori ABC transporter C2 (BmABCC2) has 1000-fold higher potential than B. mori cadherin-like protein as a receptor for Bacillus thuringiensis Cry1Aa toxin (Tanaka et al., 2013), the gate-opening ability of the latent pore under six extracellular loops (ECLs) of BmABCC2 was expected to be the reason for its higher potential (Heckel, 2012). In this study, cell swelling assays in Sf9 cells showed that BmABCC2 mutants lacking substrate-excreting activity retained receptor activity, indicating that the gate-opening activity of BmABCC2 is not responsible for Cry1Aa toxicity...
December 2017: Insect Biochemistry and Molecular Biology
Rong Li, Zhenzhen Yan, Juan Wang, Qisheng Song, Zhi Wang
BACKGROUND: Pardosa pseudoannulata is a prevailing spider species, and has been regarded as an important bio-control agent of insect pests in farmland of China. However, the available genomic and transcriptomic databases of P. pseudoannulata and their venom are limited, which severely hampers functional genomic analysis of P. pseudoannulata. Recently high-throughput sequencing technology has been proved to be an efficient tool for profiling the transcriptome of relevant non-target organisms exposed to Bacillus thuringiensis (Bt) protein through food webs...
November 7, 2017: BMC Biotechnology
Bing Wang, Haiwen Wang, Jing Xiong, Qiaoni Zhou, Huan Wu, Liqiu Xia, Lin Li, Ziquan Yu
Cry6A represents a novel family of nematicidal crystal proteins from Bacillus thuringiensis. It has distinctive architecture as well as mechanism of action from Cry5B, a highly focused family of nematicidal crystal proteins, and even from other insecticidal crystal proteins containing the conserved three-domain. However, how nematode defends against Cry6A toxin remains obscure. In this study, the global defense pattern of Caenorhabditis elegans against Cry6Aa2 toxin was investigated by proteomic analysis. In response to Cry6Aa2, 12 proteins with significantly altered abundances were observed from worms, participating in innate immune defense, insulin-like receptor (ILR) signaling pathway, energy metabolism, and muscle assembly...
October 26, 2017: Scientific Reports
Rahul Banerjee, James Hasler, Robert Meagher, Rodney Nagoshi, Lucas Hietala, Fangneng Huang, Kenneth Narva, Juan Luis Jurat-Fuentes
Evolution of resistance threatens sustainability of transgenic crops producing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt). The fall armyworm (Spodoptera frugiperda) is a devastating pest of corn in the Western Hemisphere initially controlled by transgenic Bt corn producing the Cry1Fa insecticidal protein (event TC1507). However field-evolved resistance to TC1507 was observed in Puerto Rico in 2007 and has subsequently been reported in a number of locations in North and South America...
September 7, 2017: Scientific Reports
Tiantao Zhang, Brad S Coates, Yueqin Wang, Yidong Wang, Shuxiong Bai, Zhenying Wang, Kanglai He
The Asian corn borer (ACB), Ostrinia furnacalis (Lepidoptera: Crambidae), is a highly destructive pest of cultivated maize throughout East Asia. Bacillus thuringiensis (Bt) crystalline protein (Cry) toxins cause mortality by a mechanism involving pore formation or signal transduction following toxin binding to receptors along the midgut lumen of susceptible insects, but this mechanism and mutations therein that lead to resistance are not fully understood. In the current study, quantitative comparisons were made among midgut expressed transcripts from O...
2017: International Journal of Biological Sciences
Donna R Farmer, Thomas C Edrington, Colton R Kessenich, Cunxi Wang, Jay S Petrick
Many insect-protected crops express insecticidal crystal (Cry) proteins derived from the soil bacterium Bacillus thuringiensis (Bt), including both naturally-occurring Cry proteins and chimeric Cry proteins created through biotechnology. The Cry51Aa2 protein is a naturally-occurring Cry protein that was modified to increase its potency and expand its insect activity spectrum through amino acid sequence changes. The improved Cry51Aa2 variant, Cry51Aa2.834_16, and other developmental variants belong to the ETX_MTX2 family of proteins but share a low level of sequence similarity to other members of this family...
July 24, 2017: Regulatory Toxicology and Pharmacology: RTP
Jianghuai Li, Yuemin Ma, Wanli Yuan, Yutao Xiao, Chenxi Liu, Jia Wang, Jianxin Peng, Rong Peng, Mario Soberón, Alejandra Bravo, Yongbo Yang, Kaiyu Liu
Cry toxins produced by Bacillus thuringiensis (Bt) are insecticidal proteins widely used in insect control. Recently, it was shown that ATP-binding cassette transporter proteins (ABC) such as ABCC2, ABCC3, ABCG1 and ABCA2 are implicated in the insecticidal action of Cry toxins as putative receptors. However, the transcriptional regulators involved in the expression of ABC transporter genes remain unknown. Sequence analysis of promoter regions of ABCC2 gene from Helicoverpa armigera and ABCC3 gene from Spodoptera litura Sl-HP cultured cells, revealed the potential participation of Forkhead box protein A (FOXA), a transcription factor that regulates the expression of genes through remodeling chromatin...
September 2017: Insect Biochemistry and Molecular Biology
Zan Zhang, Xiaolu Teng, Weihua Ma, Fei Li
Bacillus thuringiensis (Bt) Cry toxins play an important role in the management of insect pests. Resistance to Bt toxins has been reported in many pest insects but the mechanism responsible for this resistance in rice crop pests remains largely unknown. Cadherin is one of several Bt toxin receptors. At present, only one cadherin gene, CsCAD1, has been documented in the striped rice stem borer, Chilo suppressalis. We amplified a nearly full-length transcript of another C. suppressalis cadherin gene, CsCAD2, and found that it has a different expression pattern to CsCAD1...
July 20, 2017: Scientific Reports
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