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Bacillus thuringiensis is a gram-positive, soil-dwelling bacterium, the most commonly used biological pesticide worldwide. B. thuringiensis also occurs naturally in the gut of caterpillars of various types of moths and butterflies, as well on leaf surfaces, aquatic environments, animal feces, insect-rich environments, flour mills and grain-storage facilities. 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.
Genetically modified maize (corn) is a genetically modified crop. Specific maize strains have been genetically engineered to express agriculturally-desirable traits, including resistance to pests and to herbicides. Maize strains with both traits are now in use in multiple countries. GM maize has also caused controversy with respect to possible health effects, impact on other insects and impact on other plants via gene flow. One strain, called Starlink, was approved only for animal feed in the US but was found in food, leading to a series of recalls starting in 2000.
Pesticide resistance describes the decreased susceptibility of a pest population to a pesticide that was previously effective at controlling the pest. Pest species evolve pesticide resistance via natural selection: the most resistant specimens survive and pass on their acquired heritable changes traits to their offspring. If a pest has resistance then that will reduce the pesticide's efficacy – efficacy and resistance are inversely related.
In evolutionary biology, an evolutionary arms race is an ongoing struggle between competing sets of co-evolving genes, phenotypic and behavioral traits that develop escalating adaptations and counter-adaptations against each other, resembling the geopolitical concept of an arms race. These are often described as examples of positive feedback. The co-evolving gene sets may be in different species, as in an evolutionary arms race between a predator species and its prey, or a parasite and its host. Alternatively, the arms race may be between members of the same species, as in the manipulation/sales resistance model of communication or as in runaway evolution or Red Queen effects. One example of an evolutionary arms race is in sexual conflict between the sexes, often described with the term Fisherian runaway. Thierry Lodé emphasized the role of such antagonistic interactions in evolution leading to character displacements and antagonistic coevolution.
The cabbage looper is a medium-sized moth in the family Noctuidae, a family commonly referred to as owlet moths. Its common name comes from its preferred host plants and distinctive crawling behavior. Cruciferous vegetables, such as cabbage, bok choy, and broccoli, are its main host plant; hence, the reference to cabbage in its common name. The larva is called a looper because it arches its back into a loop when it crawls.
Bt cotton is a genetically modified pest resistant plant cotton variety that produces an insecticide to combat bollworm.
The diamondback moth, sometimes called the cabbage moth, is a moth species of the family Plutellidae and genus Plutella. The small, grayish-brown moth sometimes has a cream-colored band that forms a diamond along its back. The species may have originated in Europe, South Africa, or the Mediterranean region, but it has now spread worldwide.
Pore-forming proteins are usually produced by bacteria, and include a number of protein exotoxins but may also be produced by other organisms such as apple snails that produce perivitellin-2 or earthworms, who produce lysenin. They are frequently cytotoxic, as they create unregulated pores in the membrane of targeted cells.
MON 863 is a genetically engineered variety of maize produced by Monsanto. It is genetically altered to express a modified version of Cry3Bb1, a delta endotoxin which originates from Bacillus thuringiensis. This protects the plant from corn rootworm. Unlike MON 810, Bt 11, and Bt 176 which each produce a modified Cry1Ab, MON 863 instead produces a modified Cry3Bb1 toxin and contains nptII, a marker gene for antibiotic resistance.
Delta endotoxins (δ-endotoxins) are a family of pore-forming toxins produced by Bacillus thuringiensis species of bacteria. They are useful for their insecticidal action and are the primary toxin produced by the genetically modified (GM) Bt maize/corn and other GM crops. During spore formation the bacteria produce crystals of such proteins that are also known as parasporal bodies, next to the endospores; as a result some members are known as a parasporin. The Cyt (cytolytic) toxin group is another group of delta-endotoxins formed in the cytoplasm. VIP toxins are formed at other stages of the life cycle.
Lactonase (EC 3.1.1.81, acyl-homoserine lactonase; systematic name N-acyl-L-homoserine-lactone lactonohydrolase) is a metalloenzyme, produced by certain species of bacteria, which targets and inactivates acylated homoserine lactones (AHLs). It catalyzes the reaction
The MON 810 corn is a genetically modified maize used around the world. It is a Zea mays line known as YieldGard from the company Monsanto. This plant is a genetically modified organism (GMO) designed to combat crop loss due to insects. There is an inserted gene in the DNA of MON 810 which allows the plant to make a protein that harms insects that try to eat it. The inserted gene is from the Bacillus thuringiensis which produces the Bt protein that is poisonous to insects in the order Lepidoptera, including the European corn borer.
María Alejandra Bravo de la Parra is a Mexican biochemist who was laureated with the 2010 L'Oréal-UNESCO Award for Women in Science – Latin America for her work on a bacterial toxin that acts as a powerful insecticide. Bravo has co-authored multiple papers with her husband Mario Soberon.
The southwestern corn borer, Diatraea grandiosella, is a moth belonging to the sub-order Heterocera. Like most moths, The southwestern corn borer undergoes complete metamorphosis developing as an egg, larva (caterpillar), pupa and adult. It is capable of entering diapause in its larva stage and under the conditions of a precise photoperiod. Growth and development are regulated by juvenile hormones. The southwestern corn borer has an extensive range. It occurs in Mexico and in Alabama, Arizona, Arkansas, Colorado, Illinois, Indiana, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Nebraska, New Mexico, Oklahoma, Tennessee, and Texas.
A genetically modified tomato, or transgenic tomato, is a tomato that has had its genes modified, using genetic engineering. The first trial genetically modified food was a tomato engineered to have a longer shelf life, which was on the market briefly beginning on May 21, 1994. The first direct consumption tomato was approved in Japan in 2021. Primary work is focused on developing tomatoes with new traits like increased resistance to pests or environmental stresses. Other projects aim to enrich tomatoes with substances that may offer health benefits or be more nutritious. As well as aiming to produce novel crops, scientists produce genetically modified tomatoes to understand the function of genes naturally present in tomatoes.
Wilhelm Boland is a German chemist.
Cry1Ac protoxin is a crystal protein produced by the gram-positive bacterium, Bacillus thuringiensis (Bt) during sporulation. Cry1Ac is one of the delta endotoxins produced by this bacterium which act as insecticides. Because of this, the genes for these have been introduced into commercially important crops by genetic engineering in order to confer pest resistance on those plants.
The agriculture industry in Puerto Rico constitutes over $800 million or about 0.69% of the island's gross domestic product (GDP) in 2020. Currently the sector accounts for 15% of the food consumed locally. Experts from the University of Puerto Rico argued that these crops could cover approximately 30% of the local demand, particularly that of smaller vegetables such as tomatoes, lettuce, etc. and several kinds of tubers that are currently being imported. The existence of a thriving agricultural economy has been prevented due to a shift in priorities towards industrialization, bureaucratization, mismanagement of terrains, lack of alternative methods and a deficient workforce. Its geographical location within the Caribbean exacerbates these issues, making the scarce existing crops propense to the devastating effects of Atlantic hurricanes.
Cry6Aa is a toxic crystal protein generated by the bacterial family Bacillus thuringiensis during sporulation. This protein is a member of the alpha pore forming toxins family, which gives it insecticidal qualities advantageous in agricultural pest control. Each Cry protein has some level of target specificity; Cry6Aa has specific toxic action against coleopteran insects and nematodes. The corresponding B. thuringiensis gene, cry6aa, is located on bacterial plasmids. Along with several other Cry protein genes, cry6aa can be genetically recombined in Bt corn and Bt cotton so the plants produce specific toxins. Insects are developing resistance to the most commonly inserted proteins like Cry1Ac. Since Cry6Aa proteins function differently than other Cry proteins, they are combined with other proteins to decrease the development of pest resistance. Recent studies suggest this protein functions better in combination with other virulence factors such as other Cry proteins and metalloproteinases.>
Cry34Ab1 is one member of a binary Bacillus thuringiensis (Bt) crystal protein set isolated from Bt strain PS149B1. The protein exists as a 14 kDa aegerolysin that, in presence of Cry35Ab1, exhibits insecticidal activity towards Western Corn Rootworm. The protein has been transformed into maize plants under the commercialized events 4114 (DP-ØØ4114-3) by Pioneer Hi-Bred and 59122 (DAS-59122-7) by Dow AgroSciences. These events have, in turn, been bred into multiple trait stacks in additional products.
References
- ↑ MPI for Chemical Ecology Website
- ↑ Borrowed Genes: Keys to Evolutionary Novelty in Plant-Insect Interactions Yearbook of the Max Planck Society 2007
- ↑ Digestion and immunity in herbivorous insect larvae Yearbook of the Max Planck Society 2010
- ↑ New bacteria toxins against resistant insect pests MPG News, Oct. 19, 2011
- ↑ The small E/Z difference and its consequence MPG News, July 1, 2010
- ↑ "Woodward Medallists at the University of Melbourne". Archived from the original on 2012-03-18. Retrieved 2012-03-01.
