Bacillus thuringiensis: Difference between revisions
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[[File:Bacillus thuringiensis.jpg|thumb|[[Gram stain]] of ''Bacillus thuringiensis'' under 1000 × magnification]] | [[File:Bacillus thuringiensis.jpg|thumb|[[Gram stain]] of ''Bacillus thuringiensis'' under 1000 × magnification]] | ||
'''''Bacillus thuringiensis''''' (or '''Bt''') is a [[gram-positive bacteria|gram-positive]], soil-dwelling [[bacterium]], the most commonly used [[biological pesticide]] worldwide. ''B. thuringiensis'' also occurs naturally in the gut of [[caterpillar]]s of various types of [[moth]]s and [[butterfly|butterflies]], as well as on leaf surfaces, aquatic environments, animal feces, insect-rich environments, flour mills and grain-storage facilities.<ref name=Brock>{{cite book | veditors = Madigan MT, Martinko JM |title=Brock Biology of Microorganisms |edition=11th |publisher=Prentice Hall |year=2005 |isbn=978-0-13-144329-7}}{{page needed|date=February 2013}}</ref><ref name = effective>{{cite thesis | vauthors = du Rand N |title=Isolation of Entomopathogenic Gram Positive Spore Forming Bacteria Effective Against Coleoptera | degree = PhD |publisher=University of KwaZulu-Natal |location= Pietermaritzburg, South Africa |date=July 2009 |hdl=10413/1235}}{{page needed|date=February 2013}}</ref> It has also been observed to parasitize moths such as ''[[Cadra calidella]]''—in laboratory experiments working with ''C. calidella'', many of the moths were diseased due to this parasite.<ref>{{cite journal | vauthors = Cox PD | year = 1975 | title = The influence of photoperiod on the life-cycles of Ephestia calidella (Guenee) and Ephestia figulilella Gregson (Lepidoptera: Phycitidae) | journal = J. Stored Prod. Res. | volume = 11 | issue = 2 | pages = 77 | doi = 10.1016/0022-474X(75)90043-0 }}</ref> | '''''Bacillus thuringiensis''''' (or '''Bt''') is a [[gram-positive bacteria|gram-positive]], soil-dwelling [[bacterium]], and is the most commonly used [[biological pesticide]] worldwide. ''B. thuringiensis'' also occurs naturally in the gut of [[caterpillar]]s of various types of [[moth]]s and [[butterfly|butterflies]], as well as on leaf surfaces, aquatic environments, animal feces, insect-rich environments, flour mills and grain-storage facilities.<ref name=Brock>{{cite book | veditors = Madigan MT, Martinko JM |title=Brock Biology of Microorganisms |edition=11th |publisher=Prentice Hall |year=2005 |isbn=978-0-13-144329-7}}{{page needed|date=February 2013}}</ref><ref name = effective>{{cite thesis | vauthors = du Rand N |title=Isolation of Entomopathogenic Gram Positive Spore Forming Bacteria Effective Against Coleoptera | degree = PhD |publisher=University of KwaZulu-Natal |location= Pietermaritzburg, South Africa |date=July 2009 |hdl=10413/1235}}{{page needed|date=February 2013}}</ref> It has also been observed to parasitize moths such as ''[[Cadra calidella]]''—in laboratory experiments working with ''C. calidella'', many of the moths were diseased due to this parasite.<ref>{{cite journal | vauthors = Cox PD | year = 1975 | title = The influence of photoperiod on the life-cycles of Ephestia calidella (Guenee) and Ephestia figulilella Gregson (Lepidoptera: Phycitidae) | journal = J. Stored Prod. Res. | volume = 11 | issue = 2 | pages = 77 | doi = 10.1016/0022-474X(75)90043-0 }}</ref> | ||
During [[Endospore|sporulation]], many Bt strains produce [[crystal protein]]s (proteinaceous inclusions), called [[delta endotoxin]]s, that have [[Insecticide|insecticidal]] action. This has led to their use as insecticides, and more recently to [[genetically modified crops]] using Bt genes, such as [[Genetically modified maize#Bt corn|Bt corn]].<ref name="pmid8865583">{{cite book | vauthors = Kumar PA, Sharma RP, Malik VS | title = Advances in Applied Microbiology Volume 42 | chapter = The Insecticidal Proteins of Bacillus thuringiensis | volume = 42 | pages = 1–43 | date = 1996 | pmid = 8865583 | doi = 10.1016/s0065-2164(08)70371-x| chapter-url =https://zenodo.org/record/1259743 | isbn = 978-0-12-002642-5 }}</ref> Many crystal-producing Bt [[strain (biology)|strains]], though, do not have insecticidal properties.<ref name="Roh">{{cite journal | vauthors = Roh JY, Choi JY, Li MS, Jin BR, Je YH | title = Bacillus thuringiensis as a specific, safe, and effective tool for insect pest control | journal = Journal of Microbiology and Biotechnology | volume = 17 | issue = 4 | pages = 547–59 | date = April 2007 | pmid = 18051264 }}</ref> [[Bacillus thuringiensis israelensis]] (Bti) was discovered in 1976 by Israeli researchers Yoel Margalith and B. Goldberg in the Negev Desert of Israel. While investigating mosquito breeding sites in the region, they isolated a bacterial strain from a stagnant pond that exhibited potent larvicidal activity against various mosquito species, including ''Anopheles'', ''Culex'', and ''Aedes''.<ref>{{Cite journal | | During [[Endospore|sporulation]], many Bt strains produce [[crystal protein]]s (proteinaceous inclusions), called [[delta endotoxin]]s, that have [[Insecticide|insecticidal]] action. This has led to their use as insecticides, and more recently to [[genetically modified crops]] using Bt genes, such as [[Genetically modified maize#Bt corn|Bt corn]].<ref name="pmid8865583">{{cite book | vauthors = Kumar PA, Sharma RP, Malik VS | title = Advances in Applied Microbiology Volume 42 | chapter = The Insecticidal Proteins of Bacillus thuringiensis | volume = 42 | pages = 1–43 | date = 1996 | pmid = 8865583 | doi = 10.1016/s0065-2164(08)70371-x| chapter-url =https://zenodo.org/record/1259743 | isbn = 978-0-12-002642-5 }}</ref> Many crystal-producing Bt [[strain (biology)|strains]], though, do not have insecticidal properties.<ref name="Roh">{{cite journal | vauthors = Roh JY, Choi JY, Li MS, Jin BR, Je YH | title = Bacillus thuringiensis as a specific, safe, and effective tool for insect pest control | journal = Journal of Microbiology and Biotechnology | volume = 17 | issue = 4 | pages = 547–59 | date = April 2007 | pmid = 18051264 }}</ref> [[Bacillus thuringiensis israelensis]] (Bti) was discovered in 1976 by Israeli researchers Yoel Margalith and B. Goldberg in the Negev Desert of southern Israel. While investigating mosquito breeding sites in the region, they isolated a bacterial strain from a stagnant pond that exhibited potent larvicidal activity against various mosquito species, including ''Anopheles'', ''Culex'', and ''Aedes''.<ref>{{Cite journal |last1=Margalit |first1=J. |last2=Zomer |first2=E. |last3=Erel |first3=Z. |last4=Barak |first4=Z. |date=March 1983 |title=Development and Application of Bacillus Thuringiensis Var. Israelensis Serotype H 14 as an Effective Biological Control Agent Against Mosquitoes in Israel |url=https://www.nature.com/articles/nbt0383-74 |journal=Bio/Technology |language=en |volume=1 |issue=1 |pages=74–76 |doi=10.1038/nbt0383-74 |issn=1546-1696}}</ref> This subspecies, ''israelensis'', is now commonly used for the biological control of mosquitoes and [[fungus gnat]]s due to its effectiveness and environmental safety.<ref>{{cite web |title=Bti for Mosquito Control |url=https://www.epa.gov/mosquitocontrol/bti-mosquito-control |website=EPA.gov |access-date=28 June 2018 |publisher=US EPA |language=en|date=2016-07-05 }}</ref><ref>{{cite web |title=Fungus Gnats Management Guidelines--UC IPM |url=http://ipm.ucanr.edu/PMG/PESTNOTES/pn7448.html |website=ipm.ucanr.edu |publisher=University of California Integrated Pest Management |language=en-us}}</ref> | ||
As a toxic mechanism, ''cry'' proteins bind to specific receptors on the membranes of mid-gut ([[epithelial]]) cells of the targeted pests, resulting in their rupture. Other organisms (including humans, other animals and non-targeted insects) that lack the appropriate receptors in their gut cannot be affected by the ''cry'' protein, and therefore are not affected by Bt.<ref name="auto">{{cite web |title=Bt corn: is it worth the risk? |url=http://www.scq.ubc.ca/bt-corn-is-it-worth-the-risk/ | vauthors = Hall H |publisher=The Science Creative Quarterly|date=May 30, 2006 }}</ref><ref name="auto1">{{cite journal |vauthors=Dorsch JA, Candas M, Griko NB, Maaty WS, Midboe EG, Vadlamudi RK, Bulla LA |title=Cry1A toxins of Bacillus thuringiensis bind specifically to a region adjacent to the membrane-proximal extracellular domain of BT-R(1) in Manduca sexta: involvement of a cadherin in the entomopathogenicity of Bacillus thuringiensis |journal=Insect Biochemistry and Molecular Biology |volume=32 |issue=9 |pages=1025–36 |date=September 2002 |pmid=12213239 |doi=10.1016/S0965-1748(02)00040-1}}</ref> | As a toxic mechanism, ''cry'' proteins bind to specific receptors on the membranes of mid-gut ([[epithelial]]) cells of the targeted pests, resulting in their rupture. Other organisms (including humans, other animals and non-targeted insects) that lack the appropriate receptors in their gut cannot be affected by the ''cry'' protein, and therefore are not affected by Bt.<ref name="auto">{{cite web |title=Bt corn: is it worth the risk? |url=http://www.scq.ubc.ca/bt-corn-is-it-worth-the-risk/ | vauthors = Hall H |publisher=The Science Creative Quarterly|date=May 30, 2006 }}</ref><ref name="auto1">{{cite journal |vauthors=Dorsch JA, Candas M, Griko NB, Maaty WS, Midboe EG, Vadlamudi RK, Bulla LA |title=Cry1A toxins of Bacillus thuringiensis bind specifically to a region adjacent to the membrane-proximal extracellular domain of BT-R(1) in Manduca sexta: involvement of a cadherin in the entomopathogenicity of Bacillus thuringiensis |journal=Insect Biochemistry and Molecular Biology |volume=32 |issue=9 |pages=1025–36 |date=September 2002 |pmid=12213239 |doi=10.1016/S0965-1748(02)00040-1}}</ref> | ||
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In 1902, ''B. thuringiensis'' was first discovered in [[silkworm]]s by Japanese sericultural engineer {{nihongo|Ishiwatari Shigetane|石渡 繁胤}}. He named it ''B. sotto'',<ref>{{cite book|title=New Innovative Pesticides|url=https://books.google.com/books?id=ZR3uH7O713QC&pg=PA61|year=1977|publisher=EPA|page=61|quote= In 1915 the bacterium was re-examined and named ''Bacillus sotto''. [...] At about the same time, Beriner was isolating the organism}}</ref> using the Japanese word {{nihongo||卒倒|sottō|'collapse'}}, here referring to bacillary paralysis.<ref>{{cite book|title=Natural Enemies in the Pacific Area: Biological Control|url=https://books.google.com/books?id=ynweAQAAMAAJ|year=1967|publisher=Fukuoka Entomological Society|page=99|quote= "Sotto" in Japanese means "sudden collapse" or "fainting", and "sotto" of ''Bacillus thuringiensis'' var. ''sotto'' derives its name from the "sotto" disease.}}</ref> In 1911, German microbiologist [[Ernst Berliner]] rediscovered it when he isolated it as the cause of a disease called ''{{lang|de|[[Schlaffsucht]]}}'' in [[Ephestia kuehniella|flour moth]] caterpillars in [[Thuringia]] (hence the [[specific name (zoology)|specific name]] ''thuringiensis'', "Thuringian").<ref>{{cite book | vauthors = Reardon RC, Dubois NR, McLane W |title=''Bacillus thuringiensis'' for managing gypsy moth: a review |url= https://archive.org/details/CAT10861975 |year=1994 | work = USDA Forest Service | publisher = United States Department of Agriculture |quote= Mediterranean flour moths, ''Ephestia'' (=''Anagasta'') ''kuehniella'' (Zeller), that were found in stored grain in [[Thuringia]]}}</ref> ''B. sotto'' would later be reassigned as ''B. thuringiensis'' var. ''sotto''.<ref>{{cite book| vauthors =Steinhaus E |title=Insect Pathology: An Advanced Treatise|url=https://books.google.com/books?id=qXy7rpkMJdwC&pg=PA32|year=2012|publisher=Elsevier|isbn=978-0-323-14317-2|page=32 | quote= ''Bacillus sotto'' {{small|Ishiwata}} [→] Taxonomic reassignment: ''Bacillus thuringiensis'' var. ''sotto'' {{small|Ishiwata}}. [Heimpel and Angus, 1960]}}</ref> | In 1902, ''B. thuringiensis'' was first discovered in [[silkworm]]s by Japanese sericultural engineer {{nihongo|Ishiwatari Shigetane|石渡 繁胤}}. He named it ''B. sotto'',<ref>{{cite book|title=New Innovative Pesticides|url=https://books.google.com/books?id=ZR3uH7O713QC&pg=PA61|year=1977|publisher=EPA|page=61|quote= In 1915 the bacterium was re-examined and named ''Bacillus sotto''. [...] At about the same time, Beriner was isolating the organism}}</ref> using the Japanese word {{nihongo||卒倒|sottō|'collapse'}}, here referring to bacillary paralysis.<ref>{{cite book|title=Natural Enemies in the Pacific Area: Biological Control|url=https://books.google.com/books?id=ynweAQAAMAAJ|year=1967|publisher=Fukuoka Entomological Society|page=99|quote= "Sotto" in Japanese means "sudden collapse" or "fainting", and "sotto" of ''Bacillus thuringiensis'' var. ''sotto'' derives its name from the "sotto" disease.}}</ref> In 1911, German microbiologist [[Ernst Berliner]] rediscovered it when he isolated it as the cause of a disease called ''{{lang|de|[[Schlaffsucht]]}}'' in [[Ephestia kuehniella|flour moth]] caterpillars in [[Thuringia]] (hence the [[specific name (zoology)|specific name]] ''thuringiensis'', "Thuringian").<ref>{{cite book | vauthors = Reardon RC, Dubois NR, McLane W |title=''Bacillus thuringiensis'' for managing gypsy moth: a review |url= https://archive.org/details/CAT10861975 |year=1994 | work = USDA Forest Service | publisher = United States Department of Agriculture |quote= Mediterranean flour moths, ''Ephestia'' (=''Anagasta'') ''kuehniella'' (Zeller), that were found in stored grain in [[Thuringia]]}}</ref> ''B. sotto'' would later be reassigned as ''B. thuringiensis'' var. ''sotto''.<ref>{{cite book| vauthors =Steinhaus E |title=Insect Pathology: An Advanced Treatise|url=https://books.google.com/books?id=qXy7rpkMJdwC&pg=PA32|year=2012|publisher=Elsevier|isbn=978-0-323-14317-2|page=32 | quote= ''Bacillus sotto'' {{small|Ishiwata}} [→] Taxonomic reassignment: ''Bacillus thuringiensis'' var. ''sotto'' {{small|Ishiwata}}. [Heimpel and Angus, 1960]}}</ref> | ||
In 1976, Robert A. Zakharyan reported the presence of a plasmid in a strain of ''B. thuringiensis'' and suggested the plasmid's involvement in endospore and crystal formation.<ref>{{cite journal | vauthors = Zakharyan RA, Israelyan YK, Agabalyan AS, Tatevosyan PE, Akopyan S, Afrikyan EK |year=1979 |title=Plasmid DNA from Bacillus thuringiensis |journal=Microbiologiya |volume=48 |issue=2 |pages=226–229 |issn=0026-3656}}</ref><ref>{{cite book | veditors = Cheng TC |year=1984 |title=Pathogens of invertebrates: application in biological control and transmission mechanisms |isbn=978-0-306-41700-9 |page=[https://archive.org/details/pathogensofinver07chen/page/159 159] |url-access=registration |url=https://archive.org/details/pathogensofinver07chen/page/159 }}</ref> ''B. thuringiensis'' is closely related to ''[[Bacillus cereus|B. cereus]]'', a soil bacterium, and ''[[Bacillus anthracis|B. anthracis]]'', the cause of [[Anthrax disease|anthrax]]; the three organisms differ mainly in their [[plasmid]]s.<ref>{{cite book | vauthors = Økstad OA, Kolstø A | title=Genomics of Foodborne Bacterial Pathogens | chapter=Genomics of Bacillus Species | author2-link=Anne-Brit Kolstø | veditors = Wiedmann M, Zhang W | pages= 29–53 | publisher = Springer Science+Business Media, LLC | year = 2011 | doi = 10.1007/978-1-4419-7686-4_2 | isbn= 978-1-4419-7685-7 }}</ref>{{rp|34–35}} Like other members of the genus, all three are capable of producing [[endospore]]s.<ref name=Brock/> | In 1976, Robert A. Zakharyan reported the presence of a plasmid in a strain of ''B. thuringiensis'' and suggested the plasmid's involvement in endospore and crystal formation.<ref>{{cite journal | vauthors = Zakharyan RA, Israelyan YK, Agabalyan AS, Tatevosyan PE, Akopyan S, Afrikyan EK |year=1979 |title=Plasmid DNA from Bacillus thuringiensis |journal=Microbiologiya |volume=48 |issue=2 |pages=226–229 |issn=0026-3656}}</ref><ref>{{cite book |last1=Cheng |first1=Thomas C. | veditors = Cheng TC |year=1984 |title=Pathogens of invertebrates: application in biological control and transmission mechanisms |isbn=978-0-306-41700-9 |page=[https://archive.org/details/pathogensofinver07chen/page/159 159] |publisher=Springer |url-access=registration |url=https://archive.org/details/pathogensofinver07chen/page/159 }}</ref> ''B. thuringiensis'' is closely related to ''[[Bacillus cereus|B. cereus]]'', a soil bacterium, and ''[[Bacillus anthracis|B. anthracis]]'', the cause of [[Anthrax disease|anthrax]]; the three organisms differ mainly in their [[plasmid]]s.<ref>{{cite book | vauthors = Økstad OA, Kolstø A | title=Genomics of Foodborne Bacterial Pathogens | chapter=Genomics of Bacillus Species | author2-link=Anne-Brit Kolstø | veditors = Wiedmann M, Zhang W | pages= 29–53 | publisher = Springer Science+Business Media, LLC | year = 2011 | doi = 10.1007/978-1-4419-7686-4_2 | isbn= 978-1-4419-7685-7 }}</ref>{{rp|34–35}} Like other members of the genus, all three are capable of producing [[endospore]]s.<ref name=Brock/> | ||
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Tubulin was long thought to be specific to [[eukaryote]]s. More recently, however, several [[Prokaryote|prokaryotic]] proteins have been shown to be related to tubulin.<ref name="pmid9628483">{{cite journal | vauthors = Nogales E, Downing KH, Amos LA, Löwe J | title = Tubulin and FtsZ form a distinct family of GTPases | journal = Nature Structural Biology | volume = 5 | issue = 6 | pages = 451–8 | date = June 1998 | pmid = 9628483 | doi = 10.1038/nsb0698-451 | s2cid = 5945125 }}</ref><ref name="Jenkins_2002">{{cite journal | vauthors = Jenkins C, Samudrala R, Anderson I, Hedlund BP, Petroni G, Michailova N, Pinel N, Overbeek R, Rosati G, Staley JT | title = Genes for the cytoskeletal protein tubulin in the bacterial genus Prosthecobacter | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 99 | issue = 26 | pages = 17049–54 | date = December 2002 | pmid = 12486237 | pmc = 139267 | doi = 10.1073/pnas.012516899 | bibcode = 2002PNAS...9917049J }}</ref><ref name="Yutin_2012">{{cite journal | vauthors = Yutin N, Koonin EV | title = Archaeal origin of tubulin | journal = Biology Direct | volume = 7 | pages = 10 | date = March 2012 | pmid = 22458654 | pmc = 3349469 | doi = 10.1186/1745-6150-7-10 }}</ref><ref name="Larsen_2007">{{cite journal | vauthors = Larsen RA, Cusumano C, Fujioka A, Lim-Fong G, Patterson P, Pogliano J | title = Treadmilling of a prokaryotic tubulin-like protein, TubZ, required for plasmid stability in Bacillus thuringiensis | journal = Genes & Development | volume = 21 | issue = 11 | pages = 1340–52 | date = June 2007 | pmid = 17510284 | pmc = 1877747 | doi = 10.1101/gad.1546107 }}</ref> --> | Tubulin was long thought to be specific to [[eukaryote]]s. More recently, however, several [[Prokaryote|prokaryotic]] proteins have been shown to be related to tubulin.<ref name="pmid9628483">{{cite journal | vauthors = Nogales E, Downing KH, Amos LA, Löwe J | title = Tubulin and FtsZ form a distinct family of GTPases | journal = Nature Structural Biology | volume = 5 | issue = 6 | pages = 451–8 | date = June 1998 | pmid = 9628483 | doi = 10.1038/nsb0698-451 | s2cid = 5945125 }}</ref><ref name="Jenkins_2002">{{cite journal | vauthors = Jenkins C, Samudrala R, Anderson I, Hedlund BP, Petroni G, Michailova N, Pinel N, Overbeek R, Rosati G, Staley JT | title = Genes for the cytoskeletal protein tubulin in the bacterial genus Prosthecobacter | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 99 | issue = 26 | pages = 17049–54 | date = December 2002 | pmid = 12486237 | pmc = 139267 | doi = 10.1073/pnas.012516899 | bibcode = 2002PNAS...9917049J }}</ref><ref name="Yutin_2012">{{cite journal | vauthors = Yutin N, Koonin EV | title = Archaeal origin of tubulin | journal = Biology Direct | volume = 7 | pages = 10 | date = March 2012 | pmid = 22458654 | pmc = 3349469 | doi = 10.1186/1745-6150-7-10 }}</ref><ref name="Larsen_2007">{{cite journal | vauthors = Larsen RA, Cusumano C, Fujioka A, Lim-Fong G, Patterson P, Pogliano J | title = Treadmilling of a prokaryotic tubulin-like protein, TubZ, required for plasmid stability in Bacillus thuringiensis | journal = Genes & Development | volume = 21 | issue = 11 | pages = 1340–52 | date = June 2007 | pmid = 17510284 | pmc = 1877747 | doi = 10.1101/gad.1546107 }}</ref> --> | ||
===Species group placement=== | ===Species group placement=== | ||
''B. thuringiensis'' is placed in the ''Bacillus cereus'' group which is variously defined as | ''B. thuringiensis'' is placed in the ''Bacillus cereus'' group which is variously defined as seven closely related species: ''B. cereus'' ''sensu stricto'' (''[[Bacillus cereus|B. cereus]]''), ''[[Bacillus anthracis|B. anthracis]]'', ''B. thuringiensis'', ''[[Bacillus mycoides|B. mycoides]]'', ''[[Bacillus pseudomycoides|B. pseudomycoides]]'', and ''[[Bacillus cytotoxicus|B. cytotoxicus]]'';<ref>{{cite journal | vauthors = Guinebretière MH, Auger S, Galleron N, Contzen M, De Sarrau B, De Buyser ML, Lamberet G, Fagerlund A, Granum PE, Lereclus D, De Vos P, Nguyen-The C, Sorokin A | display-authors = 6 | title = Bacillus cytotoxicus sp. nov. is a novel thermotolerant species of the Bacillus cereus Group occasionally associated with food poisoning | journal = International Journal of Systematic and Evolutionary Microbiology | volume = 63 | issue = Pt 1 | pages = 31–40 | date = January 2013 | pmid = 22328607 | doi = 10.1099/ijs.0.030627-0 | s2cid = 2407509 }}</ref> or as six species in a ''Bacillus cereus'' sensu lato: ''[[Bacillus weihenstephanensis|B. weihenstephanensis]]'', ''B. mycoides'', ''B. pseudomycoides'', ''B. cereus'', ''B. thuringiensis'', and ''B. anthracis''. Within this grouping ''B.t.'' is more closely related to ''B.ce.'' It is more distantly related to ''B.w.'', ''B.m.'', ''B.p.'', and ''B.cy.''<ref name="Kolsto-et-al-2009">{{cite journal | vauthors = Kolstø AB, Tourasse NJ, Økstad OA | title = What sets Bacillus anthracis apart from other Bacillus species? | journal = Annual Review of Microbiology | volume = 63 | issue = 1 | pages = 451–476 | year = 2009 | pmid = 19514852 | doi = 10.1146/annurev.micro.091208.073255 | publisher = [[Annual Reviews (publisher)|Annual Reviews]] | author1-link = Anne-Brit Kolstø }}</ref> | ||
===Subspecies=== | ===Subspecies=== | ||
| Line 68: | Line 68: | ||
Common with ''B. cereus'' but so far not found elsewhere – including in other members of the species group – are the [[efflux pump]] [[BC3663]], the [[N-acyl-L-amino-acid amidohydrolase|''N''-acyl-{{small|L}}-amino-acid amidohydrolase]] [[BC3664]], and the [[methyl-accepting chemotaxis protein]] [[BC5034]].<ref name="Kolsto-et-al-2009" /> | Common with ''B. cereus'' but so far not found elsewhere – including in other members of the species group – are the [[efflux pump]] [[BC3663]], the [[N-acyl-L-amino-acid amidohydrolase|''N''-acyl-{{small|L}}-amino-acid amidohydrolase]] [[BC3664]], and the [[methyl-accepting chemotaxis protein]] [[BC5034]].<ref name="Kolsto-et-al-2009" /> | ||
==Mechanism of insecticidal action== | ==Mechanism of insecticidal action== | ||
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Spores and crystalline insecticidal proteins produced by ''B. thuringiensis'' have been used to control insect pests since the 1920s and are often applied as liquid sprays and donut pellets.<ref name="review">{{cite journal | vauthors = Lemaux PG | title = Genetically Engineered Plants and Foods: A Scientist's Analysis of the Issues (Part I) | journal = Annual Review of Plant Biology | volume = 59 | pages = 771–812 | year = 2008 | pmid = 18284373 | doi = 10.1146/annurev.arplant.58.032806.103840 }}</ref> They are now used as specific [[insecticide]]s under trade names such as DiPel, Thuricide, and Mosquito Dunks.<ref>{{Cite web |date=2024-08-09 |title=This Mosquito Hack ACTUALLY Works! |url=https://styleblueprint.com/everyday/mosquito-hack/ |access-date=2025-05-23 |website=styleblueprint.com |language=en-US}}</ref><ref>{{Cite web |last=Skwarecki |first=Beth |date=2024-05-02 |title=The Best Way to Keep Mosquitoes From Breeding in Your Yard |url=https://lifehacker.com/how-to-keep-mosquitoes-from-breeding-in-your-yard-1850607465 |access-date=2025-05-23 |website=Lifehacker |language=en}}</ref> Because of their specificity, these [[pesticide]]s are regarded as environmentally friendly, with little or no effect on humans, [[wildlife]], [[pollinator]]s, and most other [[beneficial insect]]s, and are used in [[organic farming]];<ref name="pmid12598644"/> however, the manuals for these products do contain many environmental and human health warnings,<ref>{{Cite web |url= http://www.cdms.net/ldat/ld4KK005.pdf |archive-url= https://web.archive.org/web/20130908063221/http://www.cdms.net/ldat/ld4KK005.pdf |url-status=dead|title=DiPelProDf data sheet | publisher = Valent U.S.A Corporation | date = 2005 |archive-date=September 8, 2013}}</ref><ref>{{Cite web |url= http://www.cdms.net/ldat/ld4KK007.pdf |archive-url=https://web.archive.org/web/20140313091246/http://www.cdms.net/ldat/ld4KK007.pdf|url-status=dead|title=DiPelProDf data sheet | publisher = Valent U.S.A Corporation | date = 2009 |archive-date=March 13, 2014}}</ref> and a 2012 European regulatory peer review of five approved strains found, while data exist to support some claims of low toxicity to humans and the environment, the data are insufficient to justify many of these claims.<ref>{{Cite journal|title=Conclusion on the peer review of the pesticide risk assessment of the active substance Bacillus thuringiensis subsp. kurstaki (strains ABTS 351, PB 54, SA 11, SA 12, EG 2348)|date=August 8, 2012|journal=EFSA Journal|volume=10|issue=2|pages=2540|doi=10.2903/j.efsa.2012.2540|doi-access=free}}</ref> | Spores and crystalline insecticidal proteins produced by ''B. thuringiensis'' have been used to control insect pests since the 1920s and are often applied as liquid sprays and donut pellets.<ref name="review">{{cite journal | vauthors = Lemaux PG | title = Genetically Engineered Plants and Foods: A Scientist's Analysis of the Issues (Part I) | journal = Annual Review of Plant Biology | volume = 59 | pages = 771–812 | year = 2008 | pmid = 18284373 | doi = 10.1146/annurev.arplant.58.032806.103840 }}</ref> They are now used as specific [[insecticide]]s under trade names such as DiPel, Thuricide, and Mosquito Dunks.<ref>{{Cite web |date=2024-08-09 |title=This Mosquito Hack ACTUALLY Works! |url=https://styleblueprint.com/everyday/mosquito-hack/ |access-date=2025-05-23 |website=styleblueprint.com |language=en-US}}</ref><ref>{{Cite web |last=Skwarecki |first=Beth |date=2024-05-02 |title=The Best Way to Keep Mosquitoes From Breeding in Your Yard |url=https://lifehacker.com/how-to-keep-mosquitoes-from-breeding-in-your-yard-1850607465 |access-date=2025-05-23 |website=Lifehacker |language=en}}</ref> Because of their specificity, these [[pesticide]]s are regarded as environmentally friendly, with little or no effect on humans, [[wildlife]], [[pollinator]]s, and most other [[beneficial insect]]s, and are used in [[organic farming]];<ref name="pmid12598644"/> however, the manuals for these products do contain many environmental and human health warnings,<ref>{{Cite web |url= http://www.cdms.net/ldat/ld4KK005.pdf |archive-url= https://web.archive.org/web/20130908063221/http://www.cdms.net/ldat/ld4KK005.pdf |url-status=dead|title=DiPelProDf data sheet | publisher = Valent U.S.A Corporation | date = 2005 |archive-date=September 8, 2013}}</ref><ref>{{Cite web |url= http://www.cdms.net/ldat/ld4KK007.pdf |archive-url=https://web.archive.org/web/20140313091246/http://www.cdms.net/ldat/ld4KK007.pdf|url-status=dead|title=DiPelProDf data sheet | publisher = Valent U.S.A Corporation | date = 2009 |archive-date=March 13, 2014}}</ref> and a 2012 European regulatory peer review of five approved strains found, while data exist to support some claims of low toxicity to humans and the environment, the data are insufficient to justify many of these claims.<ref>{{Cite journal|title=Conclusion on the peer review of the pesticide risk assessment of the active substance Bacillus thuringiensis subsp. kurstaki (strains ABTS 351, PB 54, SA 11, SA 12, EG 2348)|date=August 8, 2012|journal=EFSA Journal|volume=10|issue=2|pages=2540|doi=10.2903/j.efsa.2012.2540|doi-access=free}}</ref> | ||
New strains of Bt are developed and introduced over time<ref>{{cite book | vauthors = Rubin AL | chapter = Microbial Pest Control Agents: Use Patterns, Registration Requirements, and Mammalian Toxicity | chapter-url = https://books.google.com/books?id=sUrLT9z9i3IC&pg=PA442 | veditors = Krieger R |title= Hayes' Handbook of Pesticide Toxicology | volume = 1 |publisher=Academic Press, imprint of Elsevier |year=2010 |pages=442–443|isbn= 978-0-08-092201-0 }}</ref> as insects develop resistance to Bt,<ref name=" | New strains of Bt are developed and introduced over time<ref>{{cite book | vauthors = Rubin AL | chapter = Microbial Pest Control Agents: Use Patterns, Registration Requirements, and Mammalian Toxicity | chapter-url = https://books.google.com/books?id=sUrLT9z9i3IC&pg=PA442 | veditors = Krieger R |title= Hayes' Handbook of Pesticide Toxicology | volume = 1 |publisher=Academic Press, imprint of Elsevier |year=2010 |pages=442–443|isbn= 978-0-08-092201-0 }}</ref><ref>{{cite web|title= New Biological Option for Pod Borer Control in Red Gram|url= https://peptechbio.com/a-new-biological-option-for-pod-borer-control-in-red-gram/|website= Peptech Biosciences Ltd. |date= 2026-04-07| access-date=2026-04-16}}</ref> as insects develop resistance to Bt,<ref name="Charles"/><ref name="Gassmann"/><ref name="Gao">{{cite journal |last1=Gao |first1=Yulin |last2=Alyokhin |first2=Andrei |last3=Prager |first3=Sean M. |last4=Reitz |first4=Stuart |last5=Huseth |first5=Anders |title=Complexities in the Implementation and Maintenance of Integrated Pest Management in Potato |journal=Annual Review of Entomology |date=28 January 2025 |volume=70 |issue= |pages=45–63 |doi=10.1146/annurev-ento-120523-023156 |url=https://www.annualreviews.org/content/journals/10.1146/annurev-ento-120523-023156#right-ref-B147 |language=en |issn=0066-4170}}</ref>. Companies modify organisms, use [[genetic engineering]] to improve crystal size and increase pesticidal activity,<ref>{{cite patent |url=https://www.google.com/patents/US6303382 |title=Formation of and methods for the production of large bacillus thuringiensis crystals with increased pesticidal activity | assign1 = Valent BioSciences LLC | inventor = Adams LF, Thomas MD, Sloma AP, Widner WR | country = US | number = 6303382 | gdate = 16 October 2001 | postscript = . }}</ref> or broaden the host range of Bt and obtain more effective formulations.<ref>{{cite patent |status = patent|url= https://www.google.com/patents/US5955367 |title=Production of bacillus thuringiensis integrants |number=5955367 |country =US |pridate = 1989-12-18 |pubdate = 1999-09-21| inventor = Adams LF }}</ref> Each new strain is given a unique number and registered with the U.S. EPA<ref>{{cite web|url=http://www.epa.gov/fedrgstr/EPA-PEST/2007/October/Day-26/p20828.htm|archive-url=https://web.archive.org/web/20080117134704/http://www.epa.gov/fedrgstr/EPA-PEST/2007/October/Day-26/p20828.htm|url-status=dead|archive-date=January 17, 2008|title=Pesticides; Data Requirements for Biochemical and Microbial Pesticides|publisher=U.S. Environmental Protection Agency|access-date=2022-04-09}}</ref> and allowances may be given for genetic modification depending on "its parental strains, the proposed pesticide use pattern, and the manner and extent to which the organism has been genetically modified".<ref>{{Cite web|url=https://www.law.cornell.edu/cfr/text/40/158.2100|title=40 CFR § 158.2100 - Microbial pesticides definition and applicability.|website=Law.cornell.edu|access-date=9 April 2022}}</ref> Formulations of Bt that are approved for organic farming in the US are listed at the website of the [[Organic Materials Review Institute]] (OMRI)<ref>{{cite web |url= https://www.omri.org/ubersearch/results/bacillus%20thuringiensis?type[]=materials_article&type[]=opd_generic_listing&type[]=livestock&type[]=opd_listed_product&type[]=opd_prohibited_product&type[]=opd_removed_product |title= Search: bacillus, thuringiensis |publisher=OMRI }}</ref> and several university extension websites offer advice on how to use Bt spore or protein preparations in organic farming.<ref>{{cite book | veditors = Caldwell B, Sideman E, Seaman A, Shelton A, Smart C |year=2013 |chapter=Material Fact Sheet: Bacillus thuringiensis (Bt) |chapter-url=https://web.pppmb.cals.cornell.edu/resourceguide/pdf/resource-guide-for-organic-insect-and-disease-management.pdf#116 |archive-url=https://ghostarchive.org/archive/20221009/http://web.pppmb.cals.cornell.edu/resourceguide/pdf/resource-guide-for-organic-insect-and-disease-management.pdf#116 |archive-date=2022-10-09 |url-status=live |pages=109–12 |title=Resource Guide for Organic Insect and Disease Management |edition=2nd |url=https://web.pppmb.cals.cornell.edu/resourceguide/ |isbn= 978-0-9676507-8-4}}</ref><ref name=ColoSt /> | ||
==Use of Bt genes in genetic engineering of plants for pest control== | ==Use of Bt genes in genetic engineering of plants for pest control== | ||
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===Insect resistance=== | ===Insect resistance=== | ||
Multiple insects have developed a resistance to ''B. thuringiensis''. In November 2009, [[Monsanto]] scientists found the [[pink bollworm]] had become [[Pesticide resistance|resistant]] to the first-generation [[Bt cotton]] in parts of [[Gujarat]], India - that generation expresses one Bt gene, ''Cry1Ac''. This was the first instance of Bt resistance confirmed by Monsanto anywhere in the world.<ref name=MonsantoWebCotton>{{cite web|url=http://www.monsanto.com/newsviews/Pages/india-pink-bollworm.aspx |title=Cotton in India |publisher=Monsanto.com |date=2008-11-03 |access-date=2013-07-09}}</ref><ref>{{cite journal | vauthors = Bagla P | title = India. Hardy cotton-munching pests are latest blow to GM crops | journal = Science | volume = 327 | issue = 5972 | pages = 1439 | date = March 2010 | pmid = 20299559 | doi = 10.1126/science.327.5972.1439 | bibcode = 2010Sci...327.1439B | doi-access = free }}</ref | Multiple insects have developed a resistance to ''B. thuringiensis'', often due to overuse, or to use of lower-dose applications. Overuse results in only the most resistant individuals surviving to breed, which hastens the development of a resistant population. Repeated exposure to lower doses also increases the number of resistant individuals that survive to breed. The most effective management strategy for avoiding resistance is a high-dose/refuge strategy. Areas where a high dose is used, capable of killing large numbers of pests, are partnered with nearby refuge areas where non-resistant populations continue to live. When these non-resistant insects repopulate the target area, they breed with any resistant individuals that have survived, decreasing the likelihood that a resistant population will develop.<ref name="Charles">{{cite news |last1=Charles |first1=Dan |title=The ever-tenuous success of plants engineered to kill insect foes |url=https://knowablemagazine.org/content/article/food-environment/2023/bt-crops-successes-failures |access-date=7 May 2026 |work=Knowable Magazine |publisher=Annual Reviews |date=15 May 2023 |language=en |doi=10.1146/knowable-051523-3}}</ref><ref name="Gassmann">{{cite journal |last1=Gassmann |first1=Aaron J. |last2=Reisig |first2=Dominic D. |title=Management of Insect Pests with Bt Crops in the United States |journal=Annual Review of Entomology |date=23 January 2023 |volume=68 |issue= |pages=31–49 |doi=10.1146/annurev-ento-120220-105502 |url=https://www.annualreviews.org/content/journals/10.1146/annurev-ento-120220-105502 |access-date=7 May 2026 |language=en |issn=0066-4170}}</ref> | ||
Another effective tactic is the use of "pyramided" Bt crops that target the same insect pest with multiple toxins. Individuals that can resist one toxin in a pyramid may be killed by another, decreasing the number of survivors. Refuges are still needed to delay resistance to pyramided Bt crops, by reducing the chance of a resistant population developing.<ref name="Charles"/><ref name="Gassmann"/> Another strategy involves the release sterile insects to reduce the effective breeding population.<ref name="Charles"/><ref name="Gassmann"/> | |||
In some cases, [[integrated pest management]] strategies have prolonged the effectiveness of treatments, or even eradicated pests. In other cases inappropriate use has led to failure and development of resistant strains. Mexico is an example of a highly successful approach to fighting resistance in the [[bollworm]]. Farmers were allowed to plant Bt cotton strains but Bt corn was banned. Cotton bollworms feed on both cotton and corn, so Mexico’s cornfields became an effective refuge. As of 2023, Bt-resistant bollworm populations had not emerged in Mexico. However, it can be challenging to implement integrated pest management plans effectively. The companies developing Bt crops and the farmers using them may be unwilling to use strict refuge management plans; companies want to sell their products and farmers want to increase their yields, not leave some fields unprotected.<ref name="Charles"/><ref name="Gassmann"/> | |||
In November 2009, [[Monsanto]] scientists found the [[pink bollworm]] had become [[Pesticide resistance|resistant]] to the first-generation [[Bt cotton]] in parts of [[Gujarat]], India - that generation expresses one Bt gene, ''Cry1Ac''. This was the first instance of Bt resistance confirmed by Monsanto anywhere in the world.<ref name=MonsantoWebCotton>{{cite web|url=http://www.monsanto.com/newsviews/Pages/india-pink-bollworm.aspx |title=Cotton in India |publisher=Monsanto.com |date=2008-11-03 |access-date=2013-07-09}}</ref><ref>{{cite journal | vauthors = Bagla P | title = India. Hardy cotton-munching pests are latest blow to GM crops | journal = Science | volume = 327 | issue = 5972 | pages = 1439 | date = March 2010 | pmid = 20299559 | doi = 10.1126/science.327.5972.1439 | bibcode = 2010Sci...327.1439B | doi-access = free }}</ref> Bollworm resistance to first-generation Bt cotton was also identified in Australia, China, Spain, and the United States.<ref>{{cite journal | vauthors = Tabashnik BE, Gassmann AJ, Crowder DW, Carriére Y | title = Insect resistance to Bt crops: evidence versus theory | journal = Nature Biotechnology | volume = 26 | issue = 2 | pages = 199–202 | date = February 2008 | pmid = 18259177 | doi = 10.1038/nbt1382 | s2cid = 205273664 }}</ref> Additionally, resistance to Bt was documented in field population of [[diamondback moth]] in Hawaii, the continental US, and Asia.<ref>{{cite journal | vauthors = Tabshnik BE |title=Evolution of Resistance to Bacillus Thuringiensis |journal=Annual Review of Entomology |date=January 1994 |volume= 39 |pages=47–79 |doi= 10.1146/annurev.en.39.010194.000403}}</ref> Monsanto responded by introducing a second-generation cotton with multiple Bt proteins, which was rapidly adopted.<ref name=MonsantoWebCotton /> Studies in the [[cabbage looper]] have suggested that a mutation in the membrane transporter ABCC2 can confer resistance to Bt ''Cry1Ac''.<ref>{{cite journal | vauthors = Baxter SW, Badenes-Pérez FR, Morrison A, Vogel H, Crickmore N, Kain W, Wang P, Heckel DG, Jiggins CD | title = Parallel evolution of Bacillus thuringiensis toxin resistance in lepidoptera | journal = Genetics | volume = 189 | issue = 2 | pages = 675–9 | date = October 2011 | pmid = 21840855 | pmc = 3189815 | doi = 10.1534/genetics.111.130971 }}</ref> | |||
===Secondary pests=== | ===Secondary pests=== | ||
Several studies have documented surges in "sucking pests" (which are not affected by Bt toxins) within a few years of adoption of Bt cotton. In China, the main problem has been with [[mirids]],<ref>{{cite journal | vauthors = Lu Y, Wu K, Jiang Y, Xia B, Li P, Feng H, Wyckhuys KA, Guo Y | title = Mirid bug outbreaks in multiple crops correlated with wide-scale adoption of Bt cotton in China | journal = Science | volume = 328 | issue = 5982 | pages = 1151–4 | date = May 2010 | pmid = 20466880 | doi = 10.1126/science.1187881 | bibcode = 2010Sci...328.1151L | s2cid = 2093962 | doi-access = free }}</ref><ref>{{cite conference | vauthors = Just DR, Wang S, Pinstrup-Andersen P |year=2006 |title=Tarnishing Silver Bullets: Bt Technology Adoption, Bounded Rationality and the Outbreak of Secondary Pest Infestations in China |conference=American Agricultural Economics Association Annual Meeting |location=Long Beach, CA |url=http://purl.umn.edu/21230}} | Several studies have documented surges in "sucking pests" (which are not affected by Bt toxins) within a few years of adoption of Bt cotton. In China, the main problem has been with [[mirids]],<ref>{{cite journal | vauthors = Lu Y, Wu K, Jiang Y, Xia B, Li P, Feng H, Wyckhuys KA, Guo Y | title = Mirid bug outbreaks in multiple crops correlated with wide-scale adoption of Bt cotton in China | journal = Science | volume = 328 | issue = 5982 | pages = 1151–4 | date = May 2010 | pmid = 20466880 | doi = 10.1126/science.1187881 | bibcode = 2010Sci...328.1151L | s2cid = 2093962 | doi-access = free }}</ref><ref>{{cite conference | vauthors = Just DR, Wang S, Pinstrup-Andersen P |year=2006 |title=Tarnishing Silver Bullets: Bt Technology Adoption, Bounded Rationality and the Outbreak of Secondary Pest Infestations in China |conference=American Agricultural Economics Association Annual Meeting |location=Long Beach, CA |url=http://purl.umn.edu/21230}} | ||
* {{cite news | vauthors = Lang S |date=July 25, 2006 |title=Seven-year glitch: Cornell warns that Chinese GM cotton farmers are losing money due to 'secondary' pests |newspaper=Cornell Chronicle |url= | * {{cite news | vauthors = Lang S |date=July 25, 2006 |title=Seven-year glitch: Cornell warns that Chinese GM cotton farmers are losing money due to 'secondary' pests |newspaper=Cornell Chronicle |url=https://www.news.cornell.edu/stories/July06/Bt.cotton.China.ssl.html |archive-url=https://web.archive.org/web/20060811215559/http://www.news.cornell.edu/stories/July06/Bt.cotton.China.ssl.html |archive-date=2006-08-11}}</ref> which have in some cases "completely eroded all benefits from Bt cotton cultivation".<ref>{{cite journal |doi=10.1504/IJBT.2008.018348 |title=Bt-cotton and secondary pests |year=2008 | vauthors = Wang S, Just DR, Pinstrup-Andersen P |journal=International Journal of Biotechnology |volume=10 |issue=2/3 |pages=113–21 |article-number=18348 }}</ref> The increase in sucking pests depended on local temperature and rainfall conditions and increased in half the villages studied. The increase in insecticide use for the control of these secondary insects was far smaller than the reduction in total insecticide use due to Bt cotton adoption.<ref>{{cite journal | vauthors = Wang Z, Lin H, Huang J, Hu R, Rozelle S, Pray C |doi=10.1016/S1671-2927(09)60012-2 |title=Bt Cotton in China: Are Secondary Insect Infestations Offsetting the Benefits in Farmer Fields? |year=2009 |journal=Agricultural Sciences in China |volume=8 |pages=83–90}}</ref> Another study in five provinces in China found the reduction in pesticide use in Bt cotton cultivars is significantly lower than that reported in research elsewhere, consistent with the hypothesis suggested by recent studies that more pesticide sprayings are needed over time to control emerging secondary pests, such as aphids, spider mites, and lygus bugs.<ref>{{cite journal | vauthors = Zhao JH, Ho P, Azadi H | title = Benefits of Bt cotton counterbalanced by secondary pests? Perceptions of ecological change in China | journal = Environmental Monitoring and Assessment | volume = 173 | issue = 1–4 | pages = 985–994 | date = February 2011 | pmid = 20437270 | doi = 10.1007/s10661-010-1439-y | s2cid = 1583208 }}; Erratum published 2012 Aug 5: {{cite journal | vauthors = Zhao JH, Ho P, Azadi H |doi=10.1007/s10661-012-2699-5 |title=Erratum to: Benefits of Bt cotton counterbalanced by secondary pests? Perceptions of ecological change in China |year=2012 |journal=Environmental Monitoring and Assessment |volume=184 |issue=11 |page=7079 |doi-access=free }}</ref> | ||
Similar problems have been reported in India, with both [[mealy bugs]]<ref>{{cite web | vauthors = Goswami B | work = InfoChange | url = http://infochangeindia.org/200709026463/Other/Features/Making-a-meal-of-Bt-cotton.html | archive-url = https://web.archive.org/web/20080616053151/http://infochangeindia.org/200709026463/Other/Features/Making-a-meal-of-Bt-cotton.html | archive-date = 16 June 2008 | title = Making a meal of Bt cotton | access-date = 6 April 2009 }}</ref><ref>{{cite news|url=http://www.gmwatch.org/en/news/archive/2007/7640-bug-makes-meal-of-punjab-cotton-whither-bt-magic-492007 |access-date=14 March 2018 |title=Bug makes meal of Punjab cotton, whither Bt magic? |date=4 September 2007 |newspaper=The Economic Times}}</ref> and aphids<ref>{{cite journal |doi=10.1016/j.worlddev.2010.09.008 |title=Field versus Farm in Warangal: Bt Cotton, Higher Yields, and Larger Questions |year=2011 | vauthors = Stone GD |journal=World Development |volume=39 |issue=3 |pages=387–98}}</ref> although a survey of small Indian farms between 2002 and 2008 concluded Bt cotton adoption has led to higher yields and lower pesticide use, decreasing over time.<ref>{{cite journal |doi=10.1016/j.agsy.2011.11.005 |title=Bt cotton and sustainability of pesticide reductions in India |year=2012 | vauthors = Krishna VV, Qaim M |journal=Agricultural Systems |volume=107 |pages=47–55}}</ref> | Similar problems have been reported in India, with both [[mealy bugs]]<ref>{{cite web | vauthors = Goswami B | work = InfoChange | url = http://infochangeindia.org/200709026463/Other/Features/Making-a-meal-of-Bt-cotton.html | archive-url = https://web.archive.org/web/20080616053151/http://infochangeindia.org/200709026463/Other/Features/Making-a-meal-of-Bt-cotton.html | archive-date = 16 June 2008 | title = Making a meal of Bt cotton | access-date = 6 April 2009 }}</ref><ref>{{cite news|url=http://www.gmwatch.org/en/news/archive/2007/7640-bug-makes-meal-of-punjab-cotton-whither-bt-magic-492007 |access-date=14 March 2018 |title=Bug makes meal of Punjab cotton, whither Bt magic? |date=4 September 2007 |newspaper=The Economic Times}}</ref> and aphids<ref>{{cite journal |doi=10.1016/j.worlddev.2010.09.008 |title=Field versus Farm in Warangal: Bt Cotton, Higher Yields, and Larger Questions |year=2011 | vauthors = Stone GD |journal=World Development |volume=39 |issue=3 |pages=387–98}}</ref> although a survey of small Indian farms between 2002 and 2008 concluded Bt cotton adoption has led to higher yields and lower pesticide use, decreasing over time.<ref>{{cite journal |doi=10.1016/j.agsy.2011.11.005 |title=Bt cotton and sustainability of pesticide reductions in India |year=2012 | vauthors = Krishna VV, Qaim M |journal=Agricultural Systems |volume=107 |pages=47–55}}</ref> | ||
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====Colony collapse disorder==== | ====Colony collapse disorder==== | ||
As of 2007, a new phenomenon called [[colony collapse disorder]] (CCD) began affecting [[Honey bee|bee]] hives all over North America. Initial speculation on possible causes included new parasites, pesticide use,<ref>{{cite web |url=http://www.ars.usda.gov/News/docs.htm?docid=15572 |title=ARS: Questions and Answers: Colony Collapse Disorder |work=ARS News | publisher = Agricultural Research Service, United States Department of Agriculture |date=2008-05-29 | access-date=2008-11-23| archive-url = https://web.archive.org/web/20081105121119/http://www.ars.usda.gov/News/docs.htm?docid=15572 | archive-date = 5 November 2008 | url-status= dead }}</ref> and the use of Bt transgenic crops.<ref>{{cite news | vauthors = Latsch G | title = Are GM Crops Killing Bees? |work=[[Spiegel Online]] |date=March 22, 2007 |url=http://www.spiegel.de/international/world/collapsing-colonies-are-gm-crops-killing-bees-a-473166.html}}</ref> The [[Mid-Atlantic Apiculture Research and Extension Consortium]] found no evidence that pollen from Bt crops is adversely affecting bees.<ref name=Waltz/><ref>{{cite journal |doi=10.1051/apido:2007022 |title=Effects of Bt corn pollen on honey bees: Emphasis on protocol development |year=2007 | vauthors = Rose R, Dively GP, Pettis J |journal=Apidologie |volume=38 |issue=4 |pages=368–77|s2cid=18256663 |url=https://hal.archives-ouvertes.fr/hal-00892271/document }}</ref> According to the USDA, "Genetically modified (GM) crops, most commonly Bt corn, have been offered up as the cause of CCD. But there is no correlation between where GM crops are planted and the pattern of CCD incidents. Also, GM crops have been widely planted since the late 1990s, but CCD did not appear until 2006. In addition, CCD has been reported in countries that do not allow GM crops to be planted, such as Switzerland. German researchers have noted in one study a possible correlation between exposure to Bt pollen and compromised immunity to ''[[Nosema (microsporidian)|Nosema]]''."<ref>{{cite web | publisher = United States Department of Agriculture | url = https://agresearchmag.ars.usda.gov/2012/jul/colony | title = Colony Collapse Disorder: An Incomplete Puzzle | work = Agricultural Research Magazine | date = July 2012 }}</ref> The actual cause of CCD was unknown in 2007, and scientists believe it may have multiple exacerbating causes.<ref>{{cite news |url= | As of 2007, a new phenomenon called [[colony collapse disorder]] (CCD) began affecting [[Honey bee|bee]] hives all over North America. Initial speculation on possible causes included new parasites, pesticide use,<ref>{{cite web |url=http://www.ars.usda.gov/News/docs.htm?docid=15572 |title=ARS: Questions and Answers: Colony Collapse Disorder |work=ARS News | publisher = Agricultural Research Service, United States Department of Agriculture |date=2008-05-29 | access-date=2008-11-23| archive-url = https://web.archive.org/web/20081105121119/http://www.ars.usda.gov/News/docs.htm?docid=15572 | archive-date = 5 November 2008 | url-status= dead }}</ref> and the use of Bt transgenic crops.<ref>{{cite news | vauthors = Latsch G | title = Are GM Crops Killing Bees? |work=[[Spiegel Online]] |date=March 22, 2007 |url=http://www.spiegel.de/international/world/collapsing-colonies-are-gm-crops-killing-bees-a-473166.html}}</ref> The [[Mid-Atlantic Apiculture Research and Extension Consortium]] found no evidence that pollen from Bt crops is adversely affecting bees.<ref name=Waltz/><ref>{{cite journal |doi=10.1051/apido:2007022 |title=Effects of Bt corn pollen on honey bees: Emphasis on protocol development |year=2007 | vauthors = Rose R, Dively GP, Pettis J |journal=Apidologie |volume=38 |issue=4 |pages=368–77|s2cid=18256663 |url=https://hal.archives-ouvertes.fr/hal-00892271/document }}</ref> According to the USDA, "Genetically modified (GM) crops, most commonly Bt corn, have been offered up as the cause of CCD. But there is no correlation between where GM crops are planted and the pattern of CCD incidents. Also, GM crops have been widely planted since the late 1990s, but CCD did not appear until 2006. In addition, CCD has been reported in countries that do not allow GM crops to be planted, such as Switzerland. German researchers have noted in one study a possible correlation between exposure to Bt pollen and compromised immunity to ''[[Nosema (microsporidian)|Nosema]]''."<ref>{{cite web | publisher = United States Department of Agriculture | url = https://agresearchmag.ars.usda.gov/2012/jul/colony | title = Colony Collapse Disorder: An Incomplete Puzzle | work = Agricultural Research Magazine | date = July 2012 }}</ref> The actual cause of CCD was unknown in 2007, and scientists believe it may have multiple exacerbating causes.<ref>{{cite news |url=https://news.bbc.co.uk/1/hi/sci/tech/7925397.stm |title='No proof' of bee killer theory | vauthors = McGrath M |date=5 March 2009 |work=BBC News}}</ref> | ||
==Beta-exotoxins== | ==Beta-exotoxins== | ||
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== New nomenclature for pesticidal proteins (Bt toxins) == | == New nomenclature for pesticidal proteins (Bt toxins) == | ||
''Bacillus thuringiensis'' is no longer the sole source of pesticidal proteins. The Bacterial Pesticidal Protein Resource Center (BPPRC) provides information on the rapidly expanding field of pesticidal proteins for academics, regulators, and research and development personnel.<ref>{{cite journal | vauthors = Crickmore N, Berry C, Panneerselvam S, Mishra R, Connor TR, Bonning BC | title = A structure-based nomenclature for Bacillus thuringiensis and other bacteria-derived pesticidal proteins | journal = Journal of Invertebrate Pathology | volume = 186 | | ''Bacillus thuringiensis'' is no longer the sole source of pesticidal proteins. The Bacterial Pesticidal Protein Resource Center (BPPRC) provides information on the rapidly expanding field of pesticidal proteins for academics, regulators, and research and development personnel.<ref>{{cite journal | vauthors = Crickmore N, Berry C, Panneerselvam S, Mishra R, Connor TR, Bonning BC | title = A structure-based nomenclature for Bacillus thuringiensis and other bacteria-derived pesticidal proteins | journal = Journal of Invertebrate Pathology | volume = 186 | article-number = 107438 | date = November 2021 | pmid = 32652083 | doi = 10.1016/j.jip.2020.107438 | s2cid = 220488006 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Jurat-Fuentes JL, Heckel DG, Ferré J | title = Mechanisms of Resistance to Insecticidal Proteins from ''Bacillus thuringiensis'' | journal = Annual Review of Entomology | volume = 66 | issue = 1 | pages = 121–140 | date = January 2021 | pmid = 33417820 | doi = 10.1146/annurev-ento-052620-073348 | s2cid = 231303932 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Tetreau G, Andreeva EA, Banneville AS, De Zitter E, Colletier JP | title = How Does ''Bacillus thuringiensis'' Crystallize Such a Large Diversity of Toxins? | journal = Toxins | volume = 13 | issue = 7 | pages = 443 | date = June 2021 | pmid = 34206796 | pmc = 8309854 | doi = 10.3390/toxins13070443 | doi-access = free }}</ref> | ||
== See also == | == See also == | ||