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Infection signs in Myzus persicae caused by 4 strains of Bacillus thuringiensis. (A) Diet without B. thuringiensis strain, (B) strain GP300, (C) strain GP528, (D) strain GP402, and (E) strain GP777; (a) 24 h, (b) 48 h, (c) 60 h, and (d) 80 h. (For description, see the text.)
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Summary The basic step for establishing the causal agent of a disease involving microorganisms is the application of Koch's postulates. The aim of this work was to confirm that the mortality of Myzus persicae (Sulzer) (Hemiptera: Aphididae) was due to Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) strains (GP780, GP139, GP209, GP528, GP7...
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... insects, was included as a negative control and did not show pathogenicity. A Tukey test was performed, and no significant differences were found (α = 0.05) among the strains and between Cry1Ac toxin and the control ( Table 1). The photos of infected aphids at different times illustrate some observed differ- ences between the 4 strains (Fig. 2). Figure 2A shows aphids that were not exposed to spore-crystal suspensions, whereas Figs. 2B, C, D, and E show infection signs caused by strains GP300, GP528, GP402, and GP777, ...
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... photos of infected aphids at different times illustrate some observed differ- ences between the 4 strains (Fig. 2). Figure 2A shows aphids that were not exposed to spore-crystal suspensions, whereas Figs. 2B, C, D, and E show infection signs caused by strains GP300, GP528, GP402, and GP777, respectively. ...
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... aphids that were not exposed to spore-crystal suspensions remained in constant movement, continued feeding, and did not show any change in color during the first 48 h; after 60 h, these aphids became sessile, and their green color changed to a pale greenish brown (Fig. 2A). In the aphids that were exposed to spore- crystal suspensions, the signs of infection were different with each strain, but the following general pattern of symptoms was observed ( Fig. 2B-E). During the first 24 h, the aphids were moving and feed- ing and did not show any sign of infection. After 48 to 60 h, aphids exposed to the ...
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... and did not show any change in color during the first 48 h; after 60 h, these aphids became sessile, and their green color changed to a pale greenish brown (Fig. 2A). In the aphids that were exposed to spore- crystal suspensions, the signs of infection were different with each strain, but the following general pattern of symptoms was observed ( Fig. 2B-E). During the first 24 h, the aphids were moving and feed- ing and did not show any sign of infection. After 48 to 60 h, aphids exposed to the different strains moved slowly with involuntary movements (in those exposed to strains GP300 and GP528) dur- ing feeding, and abdominal segments started to squeeze. After 60 to 72 h, the aphids ...
Citations
... As a result of research conducted by L. I. Prishepa, a high mortality rate of B. thuringiensis strains (16-91, С-19 and 22-91) against E. tibialis larvae was recorded [14,15]. As a result of the conducted research, B. thuringiensis strains against pests with piercing-sucking mouthparts also recorded high mortality rates [4]. [5,10,11]. ...
Chemical and bacterial preparations have been tested in order to fight against Robinia pseudoacacia pests Obolodiplosis robiniae and Euura tibialis, some of the most widely spread fragrant tree species in Yerevan gardens. Among the preparations used against E. Tibialis, the highest biological efficiency was registered by the chemical preparation of antion (94,0 %) with a consumption rate of 1.7 l/ha, and Bacillus thuringiensis strain (91,0 %) with a concentration of 3 l/ha among the bacterial preparations. In the case of O. robiniae, high result (94,0 %) was registered by acpeline at the rate of consumption of 1 l/ha, and again the Bt 26-70 (85,4 %) strain at a rate of 3 l/ha among the bacterial preparations. Երևանի այգիներում տարածված բուրումնավետ ծառատեսակներից՝ կեղծ ակացիայի վնասատուներ սպիտակ ակացիայի գալամլակի (Obolodiplosis robiniae) և ակացիայի սղոցողի (Euura tibialis) դեմ պայքարի նպատակով փորձարկվել են քիմիական և բակտերիական պատրաստուկներ: E. tibialis -ի դեմ կիրառվող միջոցներից առավել բարձր կենսաբանական արդյունավետություն գրանցել է 1,7 լ/հա ծախսի նորմայով անթիո (94,0 %) քիմիական պատրաստուկը, իսկ բակտերիական պատրաստուկներից 3լ/հա խտանյութ չափաքանակով Bacillus thuringiensis 26-70-ը (91,0%) շտամը: O. robiniae -ի դեպքում բարձր արդյունք (94,0 %) դրսևորել է ակպելինը՝ 1լ/հա ծախսի նորմայով, իսկ բակտերիական պատրաստուկներից կրկին 3 լ/հա խտանյութ չափաքանակով Bt 26-70-ը (85,4 %) շտամը: Для борьбы вредителей (E. tibialis и O. robiniae) ложной акации, одного из наиболее широко используемых душистых деревьев в ереванских садах были испытаны химико-бак-териальные препараты. Среди средств, применяемых против вредителя E. tibialis, наиболь-шую биологическую эффективность зарегистрировал химический препарат антио (94,0 %) при норме расхода 1,7 л/га и штамм Bt 26-70 при концентрации 3 л/га. (91,0 %). В случае Obolodiplosis robiniae результат был высоким (94,0 %) при норме 1 л/га акпелина, а также при норме 3 л/га концентрата из бактериологических препаратов Bt 26-70 (85,4 %).
... The results obtained in this study are very interesting because there are few reports on the toxicity of proteins of B. thuringiensis against sucking insects. In previous reports, we demonstrated that B. thuringiensis strains isolated from corpses of Hemiptera induced physical changes and mortality in M. persicae (Torres-Quintero et al., 2015. The results obtained in this study agree with the proposed that the toxins from B. thuringiensis are specific for a certain insect group, the strain that is isolated of an insect corpse belonging to a particular order (Lepidoptera) may be pathogenic to insects of the same order (Angus and Norris, 1968). ...
The toxins produced by Bacillus thuringiensis (Bt) are well known for their insecticidal activity against Lepidoptera, Diptera and Coleoptera; however, the sap-sucking insects (Hemiptera) are not particularly susceptible to Bt toxins. We describe the aphicidal effect of Cry toxin from Bt strain GP919 against one of the most pernicious hemipterans in the agricultural environment, Myzus persicae. The mortality bioassay shows that the strain cause mortality rates above 80% at concentration of 10 ng/µl with a LC50 of 9.01 ng/µl; whereas it showed no lethal toxicity against the lepidopteran Spodoptera frugiperda. The mayor protein (∼130 kDa) expressed by this strain was subjected to purification, solubilization and trypsin digestion, the band of ∼65 kDa which was obtained from trypsin digestion was purified by ion-exchange chromatography and was used to feed the aphid. The bioassay shows mortality rates above 85% at concentration of 10 ng/µl and the LC50 was 6.58 ng/µl. The resulting fragment from the digestion was identified by mass spectrometry and the candidate protein showed an overall 100% amino acid sequence identity to the reported Cry1Cb2 (WP 033698561.1) protein from Bt. Koch’s postulated also was carried out with the GP919 strain and also, we document the signs of infection caused by this strain. This is the first report of a Cry1Cb2 protein that is toxic to a sucking insect and this protein may become a promising environmentally friendly tool for the control of M. persicae and possible also for other sap sucking insect pests.
... Therefore, if pH condition is low, the degradation process of protein molecules will not occur, and bacteria are not toxic [6] and [7] reported there are two factors which cause B. thuringiensis to be effective in killing insects, namely the presence of spores and protein. After ingestion, the spores grow in the midgut and eventually spread throughout the hemolymph leading to [8]. For this reason, it is necessary to conduct research on the effectiveness of spores and proteins against the insects tested for M. gilvus. ...
Bacillus thuringiensis an entomopathogenic bacteria is widely used as an active bio-insecticide, including to control Macrotermes gilvus termites. The effectiveness of B. thuringiensis as a bio-insecticide can be derived from both its protein and spore activities. For this reason, research was carried out to investigate effectiveness of protein separated from spores in controlling these termites. The study was arranged in a factorial completely randomized design with two factors, namely ten isolates of B. thuringiensis (first factor) and bio-insecticide separation treatment (second factor). Propagation medium was bio-urine enriched with 5% molasses. Bio-insecticide treatment was protein and supernatant of B. thuringiensis . Isolates used were B. thuringiensis isolates indigenous South Sumatera. Results showed no differences effect among B. thuringiensis isolates. The highest spore density in a solution without separation was isolate SMR-04 (11.23 x10 ¹² spores/ml). Average spore density in supernatant treatment was MSP isolates (6.00 x 10 ¹² spores/ml). The highest mortality occurred in KJ3P1 isolates on supernatant application. LT 50 value was in range of 0.921-1.025 days. To control M. gilvus termites with protein and supernatants caused high mortality and low LT 50 value. This suggested B . thurigiensis could be a candidate for biological control agents of M. gilvus in the future.
... Most studies have analysed the biopesticidal activity of the genus Bacillus against the green peach aphid Myzus persicae, one of the most destructive pests, which causes huge crop loss (Torres-Quintero et al., 2015). The most common Bacillus species tested against M. persicae is the entomopathogenic bacterium Bacillus thuringiensis (Torres-Quintero et al., 2015). ...
... Most studies have analysed the biopesticidal activity of the genus Bacillus against the green peach aphid Myzus persicae, one of the most destructive pests, which causes huge crop loss (Torres-Quintero et al., 2015). The most common Bacillus species tested against M. persicae is the entomopathogenic bacterium Bacillus thuringiensis (Torres-Quintero et al., 2015). This bacterium produces crystalline inclusions composed of insecticidal crystal proteins (ICP) and endotoxins. ...
The biosurfactants produced by Bacillus atrophaeus L193 was examined by their use in the control of the aphid Rhopalosiphum padi in order to suggest a friendly alternative to chemical pesticides. A screening of different culture media demonstrated the highest biosurfactant production by L193 in TSB supplemented with colloidal chitin. Surfactants, which are produced in large quantities (2.04 g/L), reduce surface tension to 33 mN/m. Electrospray Q-TOFS MS analysis demonstrated that lipopeptides, such as surfactins, fengycins, bacillomycins and iturins, are the predominant metabolites present in biosurfactants produced by strain L193. Treatment with L193 surfactants led to an aphid mortality rate of 59.8% within 24 h. Microscopy analysis showed that these compounds caused insect death by affecting cuticle membranes. An evaluation of aphid feeding activity also demonstrated that aphid feeding capacity is affected by treatment with surfactants. Moreover, microbial cultures of strain L193 and their supernatants also showed high levels of activity against R. padi, which is probably due to the presence of surfactants and hydrolytic enzymes such as proteases and glucanases. This study demonstrates that B. atrophaeus L193 is an effective treatment for plants affected by aphids.
Viral diseases cause the significant loss of crop yield and a marked deterioration of its quality annually. The main directions of plant protection against viral infections are: the rehabilitation of seeds by isolating and cultivating the apical meristem in vitro, the generation of transgenic plants resistant to viral infections using genes of specific and nonspecific defense, use of plant protection preparations of a chemical and biological nature against viral vectors, the application of inductors of plant resistance, etc. Thus, there is a need to look for efficient and eco-friendly measures which can prevent viral diseases from spreading. The use of endophytes for these purposes is of great interest. Endophytes are ubiquitous microorganisms, detectable in almost all plant species. Endophytes are currently regarded as the overall pools of microorganisms, including the bacteria living in plant tissues; they considerably influence the formation of plant phenotype and its adaptation to changing environmental conditions. In this review, we discuss the mechanisms of plant interactions with endophytic microorganisms. We propose the development of a microbiome using endophytic strains of microorganisms which are known to have complex biocidal activity against causal agents of infections and harmful insects as well as the ability to display viricidal properties directly and to induce plant protective reactions along with the promotion of growth and productivity is proposed as a promising approach of plant protection against viruses. At the same time, endophytes are considered delivery vectors of genes capable of blocking the reproduction of viruses in plant tissues.
The grain aphid Sitobion avenae (Fabricius) is one of the most important cereal pests, damaging crops through sap sucking and virus transmission. Sitobion avenae harbors the secondary endosymbiont Regiella insecticola, which is highly prevalent in populations in south-central Chile and other regions of the world. In order to develop ecological alternatives for biological control, we studied the effect of applying the spores of a strain of the bacterium Bacillus subtilis on the survival and fecundity of the most prevalent genotype of S. avenae in central Chile. The strain selected was one that in previous studies had shown the ability to outcompete other bacteria. Using clones of this aphid genotype infected and uninfected with R. insecticola, we found that applying B. subtilis spores through artificial diets and spraying on leaves decreased both adult survival and nymph production. The detection of spores within the aphid body was negatively correlated with nymph production and was lower in the presence of R. insecticola when applied in diets. B. subtilis spores applied on leaves reduced the number of aphids, an effect that was stronger on aphids harboring R. insecticola. A possible interaction between endosymbiotic bacteria and bacterial antagonists within the aphid body is discussed.
Con el objetivo de encontrar aislados nativos de Bacillus thuringiensis, en el presente trabajo se realizaron aislamientos a partir de diferentes materiales obtenidos del sureste de México, en el periodo de marzo 2014 a julio 2015. Se seleccionaron colonias bacterianas con base a las características típicas del genero Bacillus y se identificaron como Bacillus thuringiensis, con base a la presencia de cristales parasporales, gen cry, gen hag, perfil de proteínas y actividad insecticida. Se obtuvo un aislado de muestras de suelo (ITCBT34) y dos de larvas de Chlosyne lacinia (ITCBT61, ITCBT62). Estos aislados presentaron amplificación de los genes cry y hag. El aislado ITCBT34 presentó cristales con morfología oval, mientras que los aislados ITCBT61 e ITCCBT62 presentaron cristales bipiramidales. Se observaron diferencias en el tamaño del fragmento producido por la amplificación del gen hag y en el perfil de proteínas de los diferentes aislados. La actividad insecticida se determinó mediante bioensayo burdo con una concentración de 10 μg cm-2. Los tres aislados causaron 100% de mortalidad de larvas de Manduca sexta a las 96 h de exposición. Los aislados ITCBT61 e ITCBT62 mostraron características morfológicas y tamaño del gen hag similares a la cepa de referencia B. thuringiensis svar. kurstaki HD1, el aislado ITCBT34 no presentó similitud, por lo que podría tratarse de una aislado no relacionado al serovar kurstaki HD1.
Forty strains of Bacillus thuringiensis Berliner (Baciliales: Bacillaceae) that were isolated from corpses of Hemiptera were assessed against Myzus persicae (Sulzer) (Hemiptera: Aphididae), an aphid that is considered one of the most destructive pests affecting the agricultural economy. Seventeen strains were significantly different from the control according to the LSD test (α = 0.05). They caused mortality rates ranging from 64.4 to 88.9% at 10 ng/μL total protein concentration, and from 71.1 to 91.1% at 100 ng/μL total protein concentration. The virulence (LC50) of these 17 strains was calculated, and 5 strains showed the highest virulence (GP777 = 10.63 ng/μL, HD1 = 9.10 ng/μL, GP528 = 7.86 ng/μL, GP402 = 7.12 ng/μL, and GP300 = 6.88 ng/μL). These strains have the potential to be used as an alternative to control M. persicae under field and covered conditions.
