Bacillus thuringiensis Characterization: Morphology, Physiology, Biochemistry, Pathotype, Cellular, and Molecular Aspects

Rabinovitch, Leon; Vivoni, Adriana Marcos; Machado, Vilmar; Knaak, Neiva; Berlitz, Diouneia Lisiane; Polanczyk, Ricardo Antônio; Fiúza, Lidia Mariana

doi:10.1007/978-3-319-56678-8_1

Cited by 7 publications

(9 citation statements)

References 93 publications

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“…The morphological characterization of the Bt inocula just prior to setting up the assays was important to confirm the presence of Bt spores and crystals, recommended for a good inoculum (Johnson et al ., ; Rabinovitch et al ., ; Mukhija & Khanna, ). The capacity of Bt strains to reach young shoots of citrus after being inoculated to the seedling roots and be acquired by D. citri nymphs that fed on them was demonstrated by the isolation and plating of Bt and recuperation of CFU followed by the detection of cry or cyt gene present in each strain by PCR with specific primers, except in the control treatment.…”

Section: Discussionmentioning

confidence: 99%

Selection of Bacillus thuringiensis strains in citrus and their pathogenicity to Diaphorina citri (Hemiptera: Liviidae) nymphs

et al. 2019

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Bacillus thuringiensis (Bt) toxins are effective in controlling insect pests either through the spraying of products or when expressed in transgenic crops. The discovery of endophytic Bt strains opened new perspectives for studies aimed at the control of sapsucking insects, such as the Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Liviidae), a vector of "Candidatus Liberibacter spp.," associated with citrus huanglongbing (HLB). In this study, translocation of endophytic Bt strains in citrus seedlings inoculated with Bt suspension delivered by soil-drench, and their systemic pathogenicity to D. citri nymphs were investigated. The pathogenicity of three wild-type Bt strains against D. citri third-instar nymphs was demonstrated. Among the 10 recombinant strains tested (each of them harboring a single cry or cyt gene), 3 can be highlighted, causing 42%-77% and 66%-90% nymphal mortality at 2 and 5 d after inoculation, respectively. The isolation of Bt cells from young citrus shoots and dead nymphs, and PCR performed with specific primers, confirmed the involvement of the Bt strains in the psyllid mortality. This is the first report showing the translocation of Bt strains from citrus seedling roots to shoots and their potential to control D. citri nymphs that fed on these soil-drench inoculated seedlings. The Bt strains that caused the highest mortality rates have the potential to be used as bioinsecticides to control D. citri and the identified genes can be used for the production of transgenic Bt citrus.

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Section: Discussionmentioning

confidence: 99%

Selection of Bacillus thuringiensis strains in citrus and their pathogenicity to Diaphorina citri (Hemiptera: Liviidae) nymphs

et al. 2019

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“…Interestingly, the effects we have characterized here are reminiscent of those observed on the target organisms Helicoverpa armigera and H. zea , Spodoptera frugiperda and Choristoneura fumiferana . Indeed, when fed with sublethal doses of Btk spores, all these target organisms display developmental delays and/or reduced pupal size [ 5 , 77 , 78 , 79 ]. Moreover, recent work has also shown that the potent pathogens P. entomophila and P. aeruginosa or huge amounts of the opportunistic bacterium Erwinia carotovora carotovora induce developmental delays and growth defects in Drosophila larvae [ 80 ].…”

Section: Discussionmentioning

confidence: 99%

“…Bt is a gram-positive spore-forming bacterium belonging to the Bacillus cereus group [ 4 ]. It was first identified and characterized for its specific entomopathogenic properties due to the presence of Cry toxins, which are produced in a crystalline form during the sporulation of bacteria [ 5 ]. Seventy-eight different strains of Bt are currently inventoried [ 6 ], producing a total of more than 300 distinct Cry toxins [ 7 ] with a spectrum of toxicity ranging from nematodes to human tumor cells [ 8 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

Bacillus thuringiensis Bioinsecticides Induce Developmental Defects in Non-Target Drosophila melanogaster Larvae

Nawrot-Esposito

Babin

Pasco

et al. 2020

Insects

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Bioinsecticides made from the bacterium Bacillus thuringiensis (Bt) are the bestselling bioinsecticide worldwide. Among Bt bioinsecticides, those based on the strain Bt subsp. kurstaki (Btk) are widely used in farming to specifically control pest lepidopteran larvae. Although there is much evidence of the lack of acute lethality of Btk products for non-target animals, only scarce data are available on their potential non-lethal developmental adverse effects. Using a concentration that could be reached in the field upon sprayings, we show that Btk products impair growth and developmental time of the non-target dipteran Drosophila melanogaster. We demonstrate that these effects are mediated by the synergy between Btk bacteria and Btk insecticidal toxins. We further show that Btk bioinsecticides trigger intestinal cell death and alter protein digestion without modifying the food intake and feeding behavior of the larvae. Interestingly, these harmful effects can be mitigated by a protein-rich diet or by adding the probiotic bacterium Lactobacillus plantarum into the food. Finally, we unravel two new cellular mechanisms allowing the larval midgut to maintain its integrity upon Btk aggression: First the flattening of surviving enterocytes and second, the generation of new immature cells arising from the adult midgut precursor cells. Together, these mechanisms participate to quickly fill in the holes left by the dying enterocytes.

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“…Interestingly, the effects we have characterized here are reminiscent of those observed on the target organisms Helicoverpa armigera and H. zea, Spodoptera frugiperda and Choristoneura fumiferana. Indeed, when fed with sublethal doses of Btk spores, all these target organisms display developmental delays and/or reduced pupal size (Bauce et al, 2006;Polanczyk and Alves, 2005;Rabinovitch et al, 2017;Sedaratian et al, 2013). Moreover, recent work has also shown that the potent pathogens P. entomophila and P. aeruginosa or huge amounts of the opportunistic bacterium Erwinia carotovora carotovora induce developmental delay and growth defects in Drosophila larvae (Houtz et al, 2019).…”

Section: Discussionmentioning

confidence: 99%

“…Bt is a Gram-positive spore-forming bacterium belonging to the Bacillus cereus group (Vilas-Boas et al, 2007). It was first identified and characterized for its specific entomopathogenic properties due to the presence of specific Cry toxins, which are produced in a crystalline form during the sporulation of bacteria (Rabinovitch et al, 2017). Seventyeight different strains of Bt are currently inventoried (http://www.bgsc.org/), producing a total of more than 300 distinct Cry toxins (http://www.lifesci.sussex.ac.uk/home/Neil_Crickmore/Bt/) having a spectrum of toxicity ranging from nematodes to human tumor cells (Adang et al, 2014;Frankenhuyzen, 2017).…”

Section: Introductionmentioning

confidence: 99%

Bacillus thuringiensisbioinsecticides induce developmental defects in non-targetDrosophila melanogasterlarvae

Nawrot-Esposito

Babin

Pasco

et al. 2020

Preprint

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Bacillus thuringiensis Characterization: Morphology, Physiology, Biochemistry, Pathotype, Cellular, and Molecular Aspects

Cited by 7 publications

References 93 publications

Selection of Bacillus thuringiensis strains in citrus and their pathogenicity to Diaphorina citri (Hemiptera: Liviidae) nymphs

Selection of Bacillus thuringiensis strains in citrus and their pathogenicity to Diaphorina citri (Hemiptera: Liviidae) nymphs

Bacillus thuringiensis Bioinsecticides Induce Developmental Defects in Non-Target Drosophila melanogaster Larvae

Bacillus thuringiensisbioinsecticides induce developmental defects in non-targetDrosophila melanogasterlarvae

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