{"title":"Genomic and toxicity analysis of Lepidopteran toxic novel Bacillus thuringiensis strain T407","authors":"Rajadurai Gothandaraman , Raghu Rajasekaran , Jayakanthan Mannu , Balasubramani Venkatasamy , Kokiladevi Eswaran , Mohankumar Subbarayalu","doi":"10.1016/j.pestbp.2025.106718","DOIUrl":null,"url":null,"abstract":"<div><div><em>Bacillus thuringiensis</em> is a gram-positive and spore-forming bacterium recognized for its pathogenicity against a broad spectrum of insect and nematode pests, and it has been extensively employed as a biopesticide. In this study, we examined the morphological, molecular, and genetic features of a native <em>Bt</em> isolate T407, which demonstrated significant toxicity against lepidopteran pests. Scanning Electron Microscopy confirmed the presence of bipyramidal and cuboidal-shaped crystals in T407. SDS-PAGE examination of spore-crystal mixtures revealed two significant protein bands at ∼135 and ∼ 65 kDa, representing Cry1 and Cry2 proteins. The presence of <em>cry</em> and <em>vip</em> gene combinations in T407 was confirmed by PCR analysis. Probit analysis estimates the LC<sub>50</sub> values of 0.771, 1.379, 2.038, and 14.997 μg/mL against <em>Plutella xylostella, Helicoverpa armigera, Spodoptera litura,</em> and <em>Spodoptera frugiperda</em>, respectively. The draft genome assembly of the <em>Bt</em> isolate T407 consists of 228 scaffolds, encompassing a total of 6,148,454 bp, with an N50 value of 93,189 bp. A total of 13 plasmids were identified in this genome through BLAST search similarity analysis. Similarly, 6631 protein-coding genes were identified in this genome with 53 tRNA, 4 rRNA, and 5 ncRNA genes. Similarly, a total of 11 insecticidal toxin proteins such as Cry1Ac5, Cry1Aa18, Cry1Ac5, Cry1Aa6, Cry1Ia42, Cry2Aa9, Cry2Ab41, Vip3Aa86, Mpp46Ab1, Vpb4Ca1, and Spp1Aa1 were identified in this <em>Bt</em> genome. In addition to insecticidal toxin genes few other toxin proteins like Zwa5A, Zwa5B, Zwa6, ChitinaseC, InhA1, InhA2, Enhancin, and Bmp1 also identified in this <em>Bt</em> genome.</div></div>","PeriodicalId":19828,"journal":{"name":"Pesticide Biochemistry and Physiology","volume":"216 ","pages":"Article 106718"},"PeriodicalIF":4.0000,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Pesticide Biochemistry and Physiology","FirstCategoryId":"97","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0048357525004316","RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Bacillus thuringiensis is a gram-positive and spore-forming bacterium recognized for its pathogenicity against a broad spectrum of insect and nematode pests, and it has been extensively employed as a biopesticide. In this study, we examined the morphological, molecular, and genetic features of a native Bt isolate T407, which demonstrated significant toxicity against lepidopteran pests. Scanning Electron Microscopy confirmed the presence of bipyramidal and cuboidal-shaped crystals in T407. SDS-PAGE examination of spore-crystal mixtures revealed two significant protein bands at ∼135 and ∼ 65 kDa, representing Cry1 and Cry2 proteins. The presence of cry and vip gene combinations in T407 was confirmed by PCR analysis. Probit analysis estimates the LC50 values of 0.771, 1.379, 2.038, and 14.997 μg/mL against Plutella xylostella, Helicoverpa armigera, Spodoptera litura, and Spodoptera frugiperda, respectively. The draft genome assembly of the Bt isolate T407 consists of 228 scaffolds, encompassing a total of 6,148,454 bp, with an N50 value of 93,189 bp. A total of 13 plasmids were identified in this genome through BLAST search similarity analysis. Similarly, 6631 protein-coding genes were identified in this genome with 53 tRNA, 4 rRNA, and 5 ncRNA genes. Similarly, a total of 11 insecticidal toxin proteins such as Cry1Ac5, Cry1Aa18, Cry1Ac5, Cry1Aa6, Cry1Ia42, Cry2Aa9, Cry2Ab41, Vip3Aa86, Mpp46Ab1, Vpb4Ca1, and Spp1Aa1 were identified in this Bt genome. In addition to insecticidal toxin genes few other toxin proteins like Zwa5A, Zwa5B, Zwa6, ChitinaseC, InhA1, InhA2, Enhancin, and Bmp1 also identified in this Bt genome.
期刊介绍:
Pesticide Biochemistry and Physiology publishes original scientific articles pertaining to the mode of action of plant protection agents such as insecticides, fungicides, herbicides, and similar compounds, including nonlethal pest control agents, biosynthesis of pheromones, hormones, and plant resistance agents. Manuscripts may include a biochemical, physiological, or molecular study for an understanding of comparative toxicology or selective toxicity of both target and nontarget organisms. Particular interest will be given to studies on the molecular biology of pest control, toxicology, and pesticide resistance.
Research Areas Emphasized Include the Biochemistry and Physiology of:
• Comparative toxicity
• Mode of action
• Pathophysiology
• Plant growth regulators
• Resistance
• Other effects of pesticides on both parasites and hosts.