Relationship between chemical properties of the soil and the occurrence of Bacillus thuringiensis

Polanczyk, Ricardo Antônio; Zanúncio, José Cola; Alves, Sérgio Batista

doi:10.1590/s0103-84782009000100001

Cited by 10 publications

(6 citation statements)

References 18 publications

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“…Bacillus thuringiensis (Bt) is often referred to as a soil microorganism simply due to the fact that it has been isolated from this environment for several years [ 34 , 35 ]. Other researchers believe that the Bt spores may only be stored in the soil since they hardly germinate there and need certain nutrients and pH levels for that to occur [ 36 , 37 ]. The native microbiota and soil characteristics, including pH, humidity, mineral and organic matter concentrations, have an immediate impact on the Bt viability, thereby affecting its growth, sporulation, germination, and protein synthesis [ 37 , 38 ].…”

Section: Discussionmentioning

confidence: 99%

Efficiency of Bacillus thuringiensis and Bacillus cereus against Rhynchophorus ferrugineus

Elsharkawy

Almasoud²,

Alsulaiman³

et al. 2022

Insects

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The Red Palm Weevil (Rhynchophorus ferrugineus (Oliv.) (Coleoptera, Dryophthoridae) is a well-known palm tree pest that has caused enormous economic damage all over the globe. Insecticides are still the primary method of controlling this pest at this period. However, field populations of RPW have been shown to be resistant to pesticides. Using Bacillus spp. might be one of the options for controlling R. ferruginous. In this study, 23 species of Bacillus spp. were isolated from the rhizosphere of date palm trees in Al Ahsa Oasis, Saudi Arabia. The isolates were identified using 16S rRNA gene sequencing. R. ferrugineus larvae and adults were tested on sugarcane pieces that were treated with the B. thuringiensis strain PDC-AHSAA1 and B. cereus strains (PDC-AHSAA2, PDC-AHSA3 and PDC-AHSA4). The LC50 values for larvae and adults were quite low when they were compared with those of the other isolated strains. The B. thuringiensis strain PDC-AHSAA1 was more effective against both the larvae and adults. The determined LC50 values for B. thuringiensis ranged from 4.19 × 107 - 3.78 × 109. After 21 days, the data on larval mortality and body weight were evaluated. The surviving larvae that were treated with the bacterial isolates did not acquire a substantial weight. For the RPW larvae and adults, the mortality and corrected mortality death rates were increased by increasing the concentration of B. thuringiensis. In conclusion, Bacillus-treated diets negatively influenced the growth and development of the RPW. This research reported on the interaction between the RPW and the rhizosphere Bacillus spp. and highlighted the tremendous potential for the development of microbial resource-based control strategies for this pest.

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Section: Discussionmentioning

confidence: 99%

Efficiency of Bacillus thuringiensis and Bacillus cereus against Rhynchophorus ferrugineus

Elsharkawy

Almasoud²,

Alsulaiman³

et al. 2022

Insects

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“…The B. thuringiensis' isolates index variation from the soil samples may be related to the soil's chemical proprieties, such as type of nutrients, acidity and soil oxygenation, that can influence the B. thuringiensis prospection and the bacterium's toxins production (Yao et al, 2002;Polanczyk et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

“…The B. thuringiensis var. israelensis (Bti) is the most powerful biological alternative for controlling some diseases' vectors around the world (Polanczyk et al, 2009;Ben-Dov, 2014). This species' larvicidal activity resides in toxic proteins encoded by the cry4Aa, cry4Ba, cry10Aa, cry11Aa, cyt1Aa, cyt1Ca and cyt2Ba genes (Berry et al, 2002;Costa et al, 2010;Ben-Dov, 2014), which are used in many commercial products indicated to the Ae.…”

Section: Introductionmentioning

confidence: 99%

Strain of Bacillus thuringiensis from Restinga, toxic to Aedes (Stegomyia) aegypti (Linnaeus) (Diptera, Culicidae)

et al. 2021

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Bacillus thuringiensis is the most commonly used entomopathogen in the control of Aedes aegypti, which is a vector for different etiological agents that cause serious infections in humans. Several studies aim to isolate strains of this bacterium from different environments, with the perspective of selecting isolates with larvicidal activity for mosquitoes. Aiming at the insecticidal action of B. thuringiensis, the present study aimed to prospect B. thuringiensis of restinga and mangrove soils from the state of Maranhão, Brazil, with toxic potential for use in the biological control of Ae. aegypti. Bioassays were performed to determine the entomopathogenic activity of the bacilli against Ae. aegypti and lethal concentrations (LC50 and CL90) were estimated after the tests. Polymerase Chain Reaction and SDS-PAGE techniques were performed to verify the gene and protein content of the isolates, respectively. The soil of the mangrove and restinga ecosystems showed potential for obtaining B. thuringiensis. This isolate, in addition to having proteins with molecular mass similar to the toxins Cry and Cyt, also presented several diptera-specific genes cry and cyt, demonstrating that it has high potential to be used in the biological control of Ae. aegypti.

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“…Others, however, consider the soil only as a storage milieu for Bt spores, as they barely germinate in these places, requiring specific nutrients and pH conditions for that [ 16 , 17 , 18 , 19 ]. The indigenous microbiota, as well as soil properties, such as pH, humidity, mineral and organic matter concentrations have a direct effect on Bt ’s survival, acting positively or negatively on germination, growth, sporulation, and production of proteins [ 18 , 20 , 21 , 22 , 23 ]. These conditions, on another hand, tend to have a much lesser effect on Bacillus cereus (a taxon very closely related to Bt ), which has shown the ability to multiply in non-sterilized soils, increasing its population up to 20% [ 17 ].…”

Section: Niches Occupied By Btmentioning

confidence: 99%

“…Moreover, Bt apparently does not have to be an obligate microbe in its association with insects, as it grows in regular media in vitro [ 12 ]. Nevertheless, the chemical properties of the assessed soils, which are widely known to interphere in Bt ’s survival [ 18 , 20 , 21 , 22 , 23 ], have not been analyzed.…”

Section: Niches Occupied By Btmentioning

confidence: 99%

Bacillus thuringiensis Is an Environmental Pathogen and Host-Specificity Has Developed as an Adaptation to Human-Generated Ecological Niches

Argôlo-Filho

Loguercio

2013

Insects

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Bacillus thuringiensis (Bt) has been used successfully as a biopesticide for more than 60 years. More recently, genes encoding their toxins have been used to transform plants and other organisms. Despite the large amount of research on this bacterium, its true ecology is still a matter of debate, with two major viewpoints dominating: while some understand Bt as an insect pathogen, others see it as a saprophytic bacteria from soil. In this context, Bt’s pathogenicity to other taxa and the possibility that insects may not be the primary targets of Bt are also ideas that further complicate this scenario. The existence of conflicting research results, the difficulty in developing broader ecological and genetics studies, and the great genetic plasticity of this species has cluttered a definitive concept. In this review, we gathered information on the aspects of Bt ecology that are often ignored, in the attempt to clarify the lifestyle, mechanisms of transmission and target host range of this bacterial species. As a result, we propose an integrated view to account for Bt ecology. Although Bt is indeed a pathogenic bacterium that possesses a broad arsenal for virulence and defense mechanisms, as well as a wide range of target hosts, this seems to be an adaptation to specific ecological changes acting on a versatile and cosmopolitan environmental bacterium. Bt pathogenicity and host-specificity was favored evolutionarily by increased populations of certain insect species (or other host animals), whose availability for colonization were mostly caused by anthropogenic activities. These have generated the conditions for ecological imbalances that favored dominance of specific populations of insects, arachnids, nematodes, etc., in certain areas, with narrower genetic backgrounds. These conditions provided the selective pressure for development of new hosts for pathogenic interactions, and so, host specificity of certain strains.

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Relationship between chemical properties of the soil and the occurrence of Bacillus thuringiensis

Cited by 10 publications

References 18 publications

Efficiency of Bacillus thuringiensis and Bacillus cereus against Rhynchophorus ferrugineus

Efficiency of Bacillus thuringiensis and Bacillus cereus against Rhynchophorus ferrugineus

Strain of Bacillus thuringiensis from Restinga, toxic to Aedes (Stegomyia) aegypti (Linnaeus) (Diptera, Culicidae)

Bacillus thuringiensis Is an Environmental Pathogen and Host-Specificity Has Developed as an Adaptation to Human-Generated Ecological Niches

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