Distribution of phenotypes among Bacillus thuringiensis strains

An extensive collection of Bacillus thuringiensis isolates from around the world were phenotypically profiled using standard biochemical tests. Six phenotypic traits occurred in 20–86% of the isolates and were useful in distinguishing isolates: production of urease (U; 20.5% of isolates), hydrolysis of esculin (E; 32.3% of isolates), acid production from salicin (A; 37.4% of isolates), acid production from sucrose (S; 34.0% of isolates), production of phospholipase C or lecithinase (L; 79.7% of isolates), and hydrolysis of starch (T; 85.8% of isolates). With the exception of acid production from salicin and hydrolysis of esculin, which were associated, the traits assorted independently. Of the 64 possible combinations of these six phenotypic characteristics, 15 combinations accounted for ca. 80% of all isolates, with the most common phenotype being TL (23.6% of isolates). Surprisingly, while the biochemical traits generally assorted independently, certain phenotypic traits associated with the parasporal crystal were correlated with certain combinations of biochemical traits. Crystals that remained attached to spores (which tended to be non-toxic to insects) were highly correlated with the phenotypes that included both L and S. Among the 15 most abundant phenotypes characterizing B. thuringiensis strains, amorphous crystals were associated with TLE, TL, T, and Ø (the absence of positive tested biochemical traits). Amorphous crystal types displayed a distinct bias toward toxicity to dipteran insects. Although all common phenotypes included B. thuringiensis isolates producing bipyramidal crystals toxic to lepidopteran insects, those with the highest abundance of these toxic crystals displayed phenotypes TLU, TLUA, TLUAE, and TLAE.     

Bacillus thuringiensis subsp. sichuansis strain MC28 produces a novel crystal protein with activity against Culex quinquefasciatus larvae

The Bacillus thuringiensis subsp. sichuansis MC28 strain produces spherical parasporal crystals during sporulation and exhibits remarkable insecticidal activity against dipteran and lepidopteran pests. We characterized a novel cry gene (cry69Aa1), which was found in the pMC95 plasmid of the MC28 strain. The cry69Aa1 gene was inserted into a shuttle vector (pSTK) and expressed in an acrystalliferous mutant B. thuringiensis HD73^?. In this transformant, a large number of spherical parasporal crystals, which were toxic to Culex quinquefasciatus (Diptera), were formed.     

Distribution, Frequency, and Diversity of Bacillus thuringiensis in an Animal Feed Mill

Bacillus thuringiensis was isolated from 36 of 50 residue samples obtained from an animal feed mill (a stored-product environment). Of 710 selected colonies having Bacillus cereus-B. thuringiensis morphology isolated from the samples, 477 were classified as B. thuringiensis because of production of parasporal delta-endotoxin crystals. There was a diverse population of B. thuringiensis, as revealed by differentiation of the isolates into 36 subgroups by using (i) their spectra of toxicity to the lepidopterans Heliothis virescens, Pieris brassicae, and Spodoptera littoralis and the dipteran Aedes aegypti and (ii) their parasporal crystal morphology. A total of 55% of the isolates were not toxic to any of these insects at the concentrations used in the bioassays; 40% of all isolates were toxic to one or more of the Lepidoptera; and 20, 1, and 1% of the isolates were toxic to only P. brassicae, H. virescens, and S. littoralis, respectively. The most frequent toxicity was toxicity to P. brassicae (36% of all isolates); 18% of the isolates were toxic to A. aegypti (5% exclusively), 10% were toxic to H. virescens, and 4% were toxic to S. littoralis. Toxicity to P. brassicae was more often linked with toxicity to H. virescens than with toxicity to S. littoralis. The frequency of toxicity was significantly greater in isolates that produced bipyramidal crystals than in isolates that produced irregular pointed, irregular spherical, rectangular, or spherical crystals.     

Screening of Brazilian Bacillus thuringiensis isolates active against Spodoptera frugiperda,Plutella xylostella and Anticarsia gemmatalis

The toxicity of a collection of 1400 isolates of Bacillus thuringiensis was assessed against the Lepidoptera Spodoptera frugiperda, Anticarsia gemmantalis and Plutella xylostella. Twenty seven isolates showed toxicity to the larvae of these insects with three isolates demonstrating significantly greater potency than the standard strain against Lepidoptera, B. thuringiensis serovar kurstaki HD1. These isolates were all found to produce bipyramidal crystals and major spore-associated protein bands of approximately 130 and 65 kDa, consistent with the detection of at least one cry1 and one cry2 family gene in each. The high level of insecticidal activity of these isolates makes them excellent candidates for further development for use in the field.     

Biological, Immunological, and Genetic Analysis of Bacillus thuringiensis Isolated from Granary in Korea

To isolate a naturally occurring novel Bacillus thuringiensis strain, we investigated the distribution, toxicity, morphology, H serotype, and gene type of B. thuringiensis from residue samples of granary in Korea. A total of 163 B. thuringiensis isolates out of 411 samples producing spore and crystal were obtained. In toxicity tests, 80% of all isolates were toxic to lepidoptera, and 12% were not toxic to any of tested insects. And dipteran-active and lepidopteran/dipteran-active isolates were rare (2% and 6%, respectively). 152 B. thuringiensis isolates produced typical rhomboidal crystals, and the remainder produced parasporal inclusions with various morphologies. Serological test showed that B. thuringiensis isolates in granary represented 12 H serotypes, indicating varied distribution of B. thuringiensis. Of these, the serotype 3ab predominated, followed by the serotype 7 and 4ac. B. thuringiensis isolates of the serotype 3ab, 4ac, 5ab, 7, 8ab, 9, and 23 were toxic to lepidoptera, and the serotype 8bd, 12, 18, and 20ac were nontoxic, while 14 isolates were untypable by 33 B. thuringiensis H antisera. The frequency of toxicity against lepidoptera and diptera was primarily highly toxic. PCR analysis using cryI gene type-specific primers showed that cryIA(b) genes are frequently found and cryIE gene exists in only one isolate. Analysis of B. thuringiensis crystals and plasmid DNAs indicated a diversity of crystal and gene types. Received: 15 January 1998 / Accepted: 18 February 1998     

Diversity analysis and characterization of Coleoptera-, Hemiptera- and Nematode-active cry genes in native isolates of Bacillus thuringiensis

Applications to combat non-lepidopteran insects are not as common as applications against lepidopteran insects. The aim of the present work was to isolate and identify Bacillus thuringiensis isolates from soil samples using five approaches, viz., analysis of crystal protein production by microscopy; detection of cry gene content by PCR, SDS-PAGE profiling; cloning and sequencing; phylogenetic analysis; and toxicity testing. Two hundred soil samples were used for isolation of B. thuringiensis and a total of 69 putative isolates of B. thuringiensis that produce parasporal crystalline inclusions were isolated from 5,267 Bacillus-like colonies. A bipyramidal inclusion was predominant in 32.2 % of the B. thuringiensis isolates compared to other shapes. Crystal protein profiling of B. thuringiensis isolates by SDS-PAGE analysis showed the presence of bands of 130, 73, 34, 25 and 13 kDa, among which 50–60 kDa bands were present abundantly. PCR analysis revealed the predominance of Coleopteran-active cry genes in these isolates. Variation in nucleotide sequences, crystal morphology and mass of crystal protein(s) purified from the isolates of B. thuringiensis revealed genetic and molecular diversity. Four strains containing Coleopteran-active cry genes showed higher toxicity against Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae) adults when compared with B. thuringiensis subsp. morrisoni pathovar tenebrionis. These results are useful in emphasizing the distribution of cry genes and for prognostication of toxicity, and may contribute to the identification of novel candidate genes for bioengineered crop protection.     

Characterization of Flagellar Antigens and Insecticidal Activities of <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> Populations in Animal Feces

In total, 287 Bacillus thuringiensis isolates, recovered from feces of 28 zoo-maintained animal species, were examined for flagellar (H) antigenicity and insecticidal activity. Serologically, 209 isolates (72.8%) were allocated to the 8 H serogroups, 4 were untypable, and 74 were untestable. Among the 8 H serotypes detected, H3abc (serovar kurstaki) predominated at a high frequency of 88.0%, followed by H6 (serovar entomocidus) with a frequency of 7.7%. Insecticidal activity was associated with 67.2% of the fecal populations: 188 isolates were toxic to both Bombyx mori (Lepidoptera: Bombycidae) and Aedes aegypti (Diptera: Culicidae), 2 isolates were specific for B. mori, and 3 isolates were toxic to A. aegypti only. Of the isolates with dual toxicity, 97.9% belonged to the serovar kurstaki, producing bipyramidal parasporal inclusions. All of the H7 (serovar aizawai) isolates were toxic to both insects. Received: 4 June 2002 / Accepted: 5 July 2002     

黑龙江省苏云金杆菌的分离及对夜蛾科昆虫高毒力菌株的筛选

【目的】为了发掘新的苏云金杆菌(Bacillus thuringiensis)的资源,在黑龙江省不同地区采集不同类型的土壤样品分离出对夜蛾科具有高毒力的菌株。【方法】采用醋酸钠选择性筛选法筛选Bt菌株,利用10对通用引物对分离株进行基因型分析,SDS-PAGE进行杀虫晶体蛋白分析,同时测定苏云金杆菌分离株对棉铃虫Helicoverpa armigera(Hübner)、甘蓝夜蛾Mamestra brassicae(Linnaeus)、斜纹夜蛾Spodoptera litura(Fabricius)的杀虫活性。【结果】从黑龙江省不同地区采集的352份不同类型的土壤样品中,共分离出46株苏云金芽孢杆菌野生菌株,出菌率为13.06%。油镜下可观察到伴孢晶体的形态有菱形、球形、镶嵌形及不规则形。结果表明产菱形晶体的菌株多含有cry1类基因,而同时产生菱形、球形及不规则形晶体的菌株则含有多种基因型。SDS-PAGE蛋白分析发现这些菌株主要表达130、90、60 ku蛋白。对其中的部分菌株进行毒力测定,结果表明有4株菌株对3种夜蛾科昆虫具有高毒力。【结论】黑龙江省苏云金芽孢杆菌分布广泛,类型多样,已获得对夜蛾科昆虫有高毒力的菌株,这对夜蛾科害虫的绿色防控及延缓其抗性具有重要意义。     

Recovery of Bacillus thuringiensis from Marine Sediments of Japan

Marine sediments from a Japanese bay were examined for the occurrence of Bacillus thuringiensis. Of 1313 colonies belonging to the Bacillus cereus/B. thuringiensis group, 22 (1.7%) were allocated to B. thuringiensis. Marine isolates of B. thuringiensis consisted of heterogeneous multiple H serogroups; 10 isolates were assigned to the eight serovars (kurstaki, sumiyoshiensis, sotto, aizawai, darmstadiensis, thompsoni, neoleonensis, and higo); two motile isolates failed to react with the reference antisera; and the others were serologically untestable. Insecticidal activities were associated with two kurstaki isolates (toxic to both Lepidoptera and Diptera) and a higo isolate (Diptera-specific). None of the parasporal inclusion proteins of the 22 isolates exhibited in vitro cytotoxic activity against two vertebrate cells, sheep erythrocytes and HeLa cells. All B. thuringiensis isolates had no halophilism, although seawater-based medium supported their growth, sporulation, and formation of parasporal inclusions. Received: 29 November 1999 / Accepted: 10 January 2000     

Novel Bacillus thuringiensis Binary Insecticidal Crystal Proteins Active on Western Corn Rootworm, Diabrotica virgifera virgifera LeConte

A new family of insecticidal crystal proteins was discovered by screening sporulated Bacillus thuringiensis cultures for oral activity against western corn rootworm (WCR) larvae. B. thuringiensis isolates PS80JJ1, PS149B1, and PS167H2 have WCR insecticidal activity attributable to parasporal inclusion bodies containing proteins with molecular masses of ca. 14 and 44 kDa. The genes encoding these polypeptides reside in apparent operons, and the 14-kDa protein open reading frame (ORF) precedes the 44-kDa protein ORF. Mutagenesis of either gene in the apparent operons dramatically reduced insecticidal activity of the corresponding recombinant B. thuringiensis strain. Bioassays performed with separately expressed, biochemically purified 14- and 44-kDa polypeptides also demonstrated that both proteins are required for WCR mortality. Sequence comparisons with other known B. thuringiensis insecticidal proteins failed to reveal homology with previously described Cry, Cyt, or Vip proteins. However, there is evidence that the 44-kDa polypeptide and the 41.9- and 51.4-kDa binary dipteran insecticidal proteins from Bacillus sphaericus are evolutionarily related. The 14- and 44-kDa polypeptides from isolates PS80JJ1, PS149B1, and PS167H2 have been designated Cry34Aa1, Cry34Ab1, and Cry34Ac1, respectively, and the 44-kDa polypeptides from these isolates have been designated Cry35Aa1, Cry35Ab1, and Cry35Ac1, respectively.     

Characterization of flagellar antigens and insecticidal activities of Bacillus thuringiensis populations in animal feces

In total, 287 Bacillus thuringiensis isolates, recovered from feces of 28 zoo-maintained animal species, were examined for flagellar (H) antigenicity and insecticidal activity. Serologically, 209 isolates (72.8%) were allocated to the 8 H serogroups, 4 were untypable, and 74 were untestable. Among the 8 H serotypes detected, H3abc (serovar kurstaki) predominated at a high frequency of 88.0%, followed by H6 (serovar entomocidus) with a frequency of 7.7%. Insecticidal activity was associated with 67.2% of the fecal populations: 188 isolates were toxic to both Bombyx mori (Lepidoptera: Bombycidae) and Aedes aegypti (Diptera: Culicidae), 2 isolates were specific for B. mori, and 3 isolates were toxic to A. aegypti only. Of the isolates with dual toxicity, 97.9% belonged to the serovar kurstaki, producing bipyramidal parasporal inclusions. All of the H7 (serovar aizawai) isolates were toxic to both insects.     

Specificity of Bacillus thuringiensis var. colmeri insecticidal delta-endotoxin is determined by differential proteolytic processing of the protoxin by larval gut proteases

The native crystal delta-endotoxin produced by Bacillus thuringiensis var. colmeri, serotype 21, is toxic to both lepidopteran (Pieris brassicae) and dipteran (Aedes aegypti) larvae. Solubilization of the crystal delta-endotoxin in alkaline reducing conditions and activation with trypsin and gut extracts from susceptible insects yielded a preparation whose toxicity could be assayed in vitro against a range of insect cell lines. After activation with Aedes aegypti gut extract the preparation was toxic to all of the mosquito cell lines but only one lepidopteran line (Spodoptera frugiperda), whereas an activated preparation produced by treatment with P. brassicae gut enzymes or trypsin was toxic only to lepidopteran cell lines. These in vitro results were paralleled by the results of in vivo bioassays. Gel electrophoretic analysis of the products of these different activation regimes suggested that a 130-kDa protoxin in the native crystal is converted to a 55-kDa lepidopteran-specific toxin by trypsin or P. brassicae enzymes and to a 52-kDa dipteran toxin by A. aegypti enzymes. Two-step activation of the 130-kDa protoxin by successive treatment with trypsin and A. aegypti enzymes further suggested that the 52-kDa dipteran toxin is derived from the 55-kDa lepidopteran toxin by enzymes specific to the mosquito gut. Confirmation of this suggestion was obtained by peptide mapping of these two polypeptides. The native crystal 130 kDa delta-endotoxin and the two insect-specific toxins all cross-reacted with antiserum to B. thuringiensis var. kurstaki P1 lepidopteran toxin. Preincubation of the two activated colmeri toxins with P1 antiserum neutralized their cytotoxicity to both lepidopteran and dipteran cell lines.     

Invertebrate pathogenicity and toxin-producing potential of strains of Bacillus thuringiensis endemic to Antarctica

Several strains of Bacillus thuringiensis were previously isolated from soil in Antarctica and appeared to have physiological adaptations to this cold, nutrient-poor environment. In spite of this they could produce abnormally large, parasporal crystals under laboratory conditions. Here, they have been further characterised for toxin genes and invertebrate pathogenicity. All of the strains were positive in PCR assays for the cry1Aa and cry2 genes. This was confirmed by sequence analysis and the parasporal crystals of all strains contained polypeptides of about 130 kDa. This potential for lepidopteran toxicity was borne out in bioassays of purified δ-endotoxins against larvae of Pieris brassicae: the LD₅₀ values of B2408 (288 μg) were comparable to that of the reference strain, HD-12 (201 μg). There was no activity against the nematode Caenorhabditis elegans in spite of the fact that all strains appeared to possess the cry6 gene. PCR screening for genes encoding other nematode-toxic classes of toxins (Cry5, 4 and 21) was negative. B. thuringiensis has never previously been shown to be toxic to Collembola (springtails) but the purified δ-endotoxins of one of the Antarctic strains showed some activity against Folsomia candida and Seira domestica (224 μg and 238 μg, respectively). It seems unlikely that the level of toxicity demonstrated against springtails would support a pathogenic life-style in nature. All of the strains were positive for genes encoding Bacillus cereus-type enterotoxins. In the absence of higher insects and mammals the ecological value of retaining the toxic capability demonstrated here is uncertain.     

Bacillus thuringiensis serovar mogi (flagellar serotype 3a3b3d), a novel serogroup with a mosquitocidal activity

The flagellated vegetative cells of the Bacillus thuringiensis strain K4 were agglutinated with the H3 reference antiserum and further, agglutinated with 3b and 3d monospecific factor sera but non-reactive for 3c and 3e factor sera. This creates a new serogroup with flagellar antigenic structure of 3a3b3d: B. thuringiensis serovar mogi. The strain K4 showed high activity against dipteran larvae, Anopheles sinensis and Culex pipienspallens while no lepidopteran toxicity. It produced ovoidal parasporal inclusions (crystals) whose SDS-PAGE protein profile consisted of several bands ranging from 75 to 30 kDa. Through the protein identification by nano-LC-ESI-IT MS analysis, the putative peptides of Cry19Ba, Cry40ORF2, Cry27Aa and Cry20Aa were detected.     

The isolates of Bacillus thuringiensis serotype 10 with a highly preferential toxicity to mosquito larvae

Comparative bacteriological and serological studies of three isolates and the reference strain of Bacillus thuringiensis subsp. darmstadiensis (serotype 10) were conducted. No difference was shown in the flagellar antigenic structure between the three isolates and the reference strain. Differences were observed in the O antigenic structures and in the following biochemical properties: lecithinase production, DNase production, arginine decarboxylase production, acid production from inulin, and malonate utilization. β-Exotoxin production was not detected in these three isolates. The reference strain produced parasporal inclusions toxic to the lepidopterous larvae but nontoxic to mosquito larvae. On the contrary, two among the three isolates, which produced spherical parasporal inclusions, were not toxic to the lepidopterous larvae but highly toxic to larvae of the mosquitoes, Culex tritaenlorhynchus, Culex molestus, and Aedes aegypti. Another isolate produced large irregular-shaped inclusions nontoxic to the insects of both orders. Accordingly, B. thuringiensis serotype 10 was divided into three groups from the viewpoint of toxicity against lepidopterous and mosquito larvae.     

Nucleotide sequence and deduced amino acid sequence of a coleopteran-active delta-endotoxin gene from Bacillus thuringiensis subsp. san diego

A gene from Bacillus thuringiensis subsp. san diego that is responsible for a delta-endotoxin active against Colorado potato beetle and some other Coleoptera was sequenced and shown to have surprising regional homology with both lepidopteran and dipteran active delta-endotoxins from other strains of B. thuringiensis. Unlike the lepidopteran active toxins from B. thuringiensis subsp. kurstaki that exist as approx. 130-kDa protoxins and form bipyramidal crystalline inclusions, the coleopteran toxic protein forms a square-shaped crystal composed of an approx. 65-kDa protein. Comparisons of the gene sequences encoding the active portions of these protoxins indicate conservation of N-terminal hydrophilic and hydrophobic regions, and suggest a distant ancestral origin for these insecticidal proteins.     

Seasonal distribution and characterization of Bacillus thuringiensis isolated from sericultural environments in Korea

To isolate naturally occurring novel Bacillus thuringiensis strains, we investigated the distribution and characteristics of B. thuringiensis from samples of sericultural farms in various regions of Korea in the spring and fall. Fifty-four B. thuringiensis strains out of 164 samples and 34 B. thuringiensis strains out of 135 samples were isolated in the spring and fall, respectively. Seventy percent of the isolates in the spring and 15% in the fall were toxic to lepidopteran larvae. Dipteran-active isolates were rare (7% in spring and 3% in fall isolation). Particularly, B. thuringiensis isolates, which are toxic to both Lepidoptera and Diptera, were widely distributed (19% in spring and 62% in fall isolation). Non-toxic isolates were also found (4% in spring and 20% in fall isolation). B. thuringiensis isolates in the sericultural farms represented 11 H serotypes; they were principally B. thuringiensis subsp. aizawai in the spring and kurstaki in the fall. B. thuringiensis isolates of serotypes 1, 3a, 3a3b, 4a4c, 6, 7 and 12 were toxic to Lepidoptera. Seventy isolates produced typical rhomboidal inclusions, and the remainder produced parasporal inclusions with various morphologies. PCR analysis using cryI gene type-specific primers showed that cryIAa and cryIC genes are frequently found in the spring and cryIAa gene is a predominant type in the fall. Toxicity, H serotype and the cryI gene contents of B. thuringiensis isolated from sericultural farms showed that distribution varied depending on the season.     

Genetic diversity and functional characterization of endophytic <Emphasis Type="BoldItalic">Bacillus thuringiensis</Emphasis> isolates from the North Western Indian Himalayas

A total of 15 endophytic Bacillus thuringiensis isolates were obtained from root nodules of six legumes (soybean, ricebean, gahat, frenchbean, lentil and pea). All of these isolates were characterized by the presence of one of two different types of crystalline inclusions (spherical and bipyramidal) and tolerance to a wide pH range (4–10; optimum 7.0) and NaCl concentrations up to 8%. Genetic diversity among the B. thuringiensis isolates was determined by repetitive extragenic palindromic PCR assays (rep-PCR) using the Bacillus cereus-repetitive extragenic palindromic, BOX, enterobacterial repetitive intergenic consensus sequence and (GTG)₅ primers. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis proteogram of the B. thuringiensis isolates revealed the presence of two major polypeptides (24.4 and 131.0 kDa). Maximum crystal protein profile was observed in the B. thuringiensis isolates producing the spherical crystal, while those isolates producing the bipyramidal crystal protein showed four four major polypeptides (24.4, 33.8, 81.2 and 131.0 kDa). The purified crystal protein profile of the B. thuringiensis isolates revealed the presence of only one major protein of 130 kDa mass. Isolates VRB1 and VLG15 possessing the cry1 and cry2 family genes demonstrated 100% mortality against first-instar larvae of the Bihar hairy caterpillar (lepidopteran pest). Our study of the ecological and molecular diversity among newly identified B. thuringiensis isolates suggests that these could be useful in planning new strategies for integrated pest management in sustainable agricultural systems.     

Expression of the full-length and 3'-spliced cry1Ab gene in the 135-kDa crystal protein minus derivative of Bacillus thuringiensis subsp. kyushuensis

Bacillus thuringiensis produces a 130–135-kDa insecticidal protein in the form of bipyramidal crystal which is toxic to lepidopteran larvae. Part of the C-terminal region of the native Cry1Ab was replaced by a heterologous sequence of Cry11Aa C-terminus to get a 3′-spliced cry1Ab gene. The full-length cry1Ab and 3′-spliced cry1Ab, which were both cloned into the E. coli–B. thuringiensis shuttle expression vector pHZB1, were expressed in a 135-kDa crystal protein minus derivative of B. thuringiensis subsp. kyushuensis (4U1-Cry⁻¹³⁵). The crystal shape of Cry1Ab proteins from both recombinants was regularly bipyramidal, while the crystal size of the intact Cry1Ab was approximately fivefold larger than the 3′-spliced Cry1Ab. In addition, these two kinds of Cry1Ab proteins had similar toxicity against Argyrogramma agnata larvae. Received: 19 October 2001 / Accepted: 7 December 2001     

Virulence of some native Bacillus thuringiensis isolates against Ephestia kuehniella (Zeller) (Lep., Pyralidae) and Pieris brassicae (Lep., Pieridae) larvae isolated from stored products of Urmia city

Bacillus thuringiensis isolates were recovered from numerous sources including soil, grain dust, plant leaves, diseased insect larvae from insectariums and sericulture environments. B. thuringiensis strains were isolated using acetate selection method with 0.025?M. concentration. The morphology of crystals was studied using light microscopy. Bioassay tests were conducted on Ephestia kuehniella (Zeller) (L.) as well as Pieris brassicae (L.). Based on the results, 35 B. thuringiensis strains were isolated from 140 samples. Majority of strains (%31.42) had bipyramidal crystals. There was a significant difference in toxicity to insects among B. thuringiensis isolates; 28.57 and 14.28% of the isolates were toxic to the larvae of P. brassicae and E. kuehniella, respectively, causing more than 50% mortality. Results indicated that B. thuringiensis isolates with insecticidal activity could be used in integrated pest management to control farm and stored product pests.