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IPM MANAGEMENT IN C OTTON F IELDS & FIELD CROPS. Transgenic Cotton & Corn with Bt ( Bacillus thuringiensis) Transgenic Cotton & Corn with Bt ( Bacillus.

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Presentation on theme: "IPM MANAGEMENT IN C OTTON F IELDS & FIELD CROPS. Transgenic Cotton & Corn with Bt ( Bacillus thuringiensis) Transgenic Cotton & Corn with Bt ( Bacillus."— Presentation transcript:

1 IPM MANAGEMENT IN C OTTON F IELDS & FIELD CROPS

2 Transgenic Cotton & Corn with Bt ( Bacillus thuringiensis) Transgenic Cotton & Corn with Bt ( Bacillus thuringiensis)

3 Bt was first discovered in 1901 by Japanese biologist Ishiwatari. In Germany 1911, Bt was isolated by Berliner in flour moth caterpillars, as the cause of a disease called Schlaffsucht In 1976, Zakharyan reported the presence of a plasmid in a strain of Bt involved in endospore insecticidal and crystal formation, called crystal proteins or Cry (proteins) toxins. Cry toxins belong to a large family known as PFT Bacillus thuringiensis

4 P ORE F ORMING T OXINS (PFT) PFT are important virulence factors produced by bacteria to kill eukaryotic cells by forming holes in the cellular membrane. They represent a diverse group of proteins with a wide range of target cells. The mode of action of PFT involves: (a) Receptor recognition. (b) Activation by proteases (protein enzymes). (c) Aaggregation into oligomeric- structures ( molecule that consists of a few monomer units ). (d) Insertion into the membrane to form ionic pores.

5 The toxin core travels across the peritrophic matrix Cry toxins interact with specific receptors called cadherin, located on the host cell surface, the brush border membrane of the gut cells. Activated by host proteases following receptor binding. A new pre-pore oligomeric structure is formatted. The new formation is insert into the membrane to form ionic pores. Pores lead to osmotic cell lysis. The toxin core travels across the peritrophic matrix Cry toxins interact with specific receptors called cadherin, located on the host cell surface, the brush border membrane of the gut cells. Activated by host proteases following receptor binding. A new pre-pore oligomeric structure is formatted. The new formation is insert into the membrane to form ionic pores. Pores lead to osmotic cell lysis. B T C RY T OXIN – M OD OF A CTION

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7 Bt is a naturally-occurring soilborne bacterium that is found worldwide. A unique feature of this bacterium: its production of crystal-like proteins (Cry) and Cytolitic (Cyt) protein families, that selectively kill specific groups of insects: Lepidoptera, Coleoptera, Diptera and also other invertebrates such as nematodes Cry proteins are delta endotoxins, insect stomach poisons that must be eaten to kill insects. Once eaten, insects stop feeding within 2 hours of a first bite and, if enough toxin is eaten, die within 2-3 days. For more than 30 years, various formulations of Bt have been used successfully against insect pests on a variety of crops. Bt is a naturally-occurring soilborne bacterium that is found worldwide. A unique feature of this bacterium: its production of crystal-like proteins (Cry) and Cytolitic (Cyt) protein families, that selectively kill specific groups of insects: Lepidoptera, Coleoptera, Diptera and also other invertebrates such as nematodes Cry proteins are delta endotoxins, insect stomach poisons that must be eaten to kill insects. Once eaten, insects stop feeding within 2 hours of a first bite and, if enough toxin is eaten, die within 2-3 days. For more than 30 years, various formulations of Bt have been used successfully against insect pests on a variety of crops. Bt as an Insecticide

8 Δ - ENDOTOXINS Historically, B.t. t oxins have been divided into two groups on the basis of target specificity: (a) Insect-specific Cry (crystal) proteins (b) Generally cytolytic Cyt proteins. δ-endotoxins are a super family of proteins that occur as crystalline inclusions in the spore-forming bacterium Bacillus thuringiensis. Considered environmentally safe insecticides. The Cry proteins are the group that is mostly being used in commercial insecticide preparations.

9 In 1981, scientists cloned the first Bt toxin gene, which led quickly to the development of the first transgenic Bt plants in the mid- 1980s. There are several strains of Bt, each with differing Cry proteins. Scientists have identified more than 60 Cry proteins.

10 Other types of Bt toxins are called Vegetative Insecticidal Proteins, or VIPs. VIPs are also considered relatively safe for non- pest species. Other classes of toxins produced by Bt have a broader spectrum of toxicity. Other Types of Bt Toxins

11 A transgenic Bt plant produces delta endotoxin or Vips controlled by a single gene in the bacteria. A modified version of this gene can be placed in plants. Plants containing this gene can produce delta endotoxin or VIP and therefore be toxic to insects that are susceptible to that form of the protein. Plant geneticists create Bt crops by inserting selected exotic DNA into the corn plant's own DNA. Seed companies select elite hybrids for the Bt transformation in order to retain important agronomic qualities for yield, harvest ability and disease resistance Transgenic Bt Plants

12 The need to increase food production to meet the food and feed demands of the world, requiring higher production, particularly in developing countries in Asia, Africa and Latin America. This demand has to meet primarily through yield increases on existing cultivated lands in order to be environmentally sustainable and cost effective. The need to increase food production to meet the food and feed demands of the world, requiring higher production, particularly in developing countries in Asia, Africa and Latin America. This demand has to meet primarily through yield increases on existing cultivated lands in order to be environmentally sustainable and cost effective. The Essential Global Needs leading Towards Production of Bt Crops The Essential Global Needs leading Towards Production of Bt Crops

13 The EPA U.S. (Environmental Protection Agency), considered 20 years of human and animal safety data before registering Bt corn. Bt proteins are not toxic to people, domestic animals, fish, or wildlife; and they have no negative impacts on the environment. The Food and Drug Administration (FDA) exempts Bt Cry proteins from residue analyses because of Bt's history of safety and because these proteins degrade rapidly. How safe is Bt and Bt Crops?

14 Three primary components of the genetic package inserted into the crop include: A. Protein gene. Bt genes, modified for improved expression in crops, produce Cry proteins. B. Promoter. A DNA sequence that regulates where, when, and to what degree, an associated gene is expressed. C. Genetic marker. The presence of a genetic marker allows seed companies to identify successful transformations. Three primary components of the genetic package inserted into the crop include: A. Protein gene. Bt genes, modified for improved expression in crops, produce Cry proteins. B. Promoter. A DNA sequence that regulates where, when, and to what degree, an associated gene is expressed. C. Genetic marker. The presence of a genetic marker allows seed companies to identify successful transformations. Bt hybrids Genetic Package

15 Some promoters limit protein production to specific parts of the plant. Example: Some promoters produce protein throughout leaves, green tissue and pollen, whereas others produce protein throughout the plant. Some promoters limit protein production to specific parts of the plant. Example: Some promoters produce protein throughout leaves, green tissue and pollen, whereas others produce protein throughout the plant. The Promoter

16 Genetic marker. Current examples of markers include genes for herbicide resistance or antibiotic resistance.

17 The genetic package is inserted into plant through a variety of plant transformation techniques Successful transformations, called "events," vary in the components of the genetic package and where this DNA is inserted into the corn DNA. The insertion site may affect Bt protein production and could affect other plant functions. Consequently, seed companies carefully scrutinize transformation events to ensure adequate production of Bt protein and no negative effects on agronomic traits.

18 Non-toxic to vertebrates unlike synthetic pesticides Very specific to particular insect pests. Reduction in sprays per season, with synthetic pesticides Very specific to particular insect pests. Suitable for small-scale farmers, no equipment and pesticide knowledge are needed Benefits both the environment and labourers’ health, Increase incomes through higher yields of healthier grain. Transgenic Bt Crops, Advantages

19 Global Area of Biotech Crops, 1996 to 2010 (Million Hectares)

20 Bt Issues There is some evidence that the prolonged use of Bt crops can create emergence of resistant insect strains or elevation in populations of insects that are naturally resistant; these would likely have emerged with the use of Bt alone.

21 Many factors contribute to the development of resistance:  Widespread use of Bt crops  High season-long mortality  Two or more generations per year.  The lack of “refuges” – small crop areas that are not GM. Many factors contribute to the development of resistance:  Widespread use of Bt crops  High season-long mortality  Two or more generations per year.  The lack of “refuges” – small crop areas that are not GM. How does resistance develop?

22 Insect resistance management (IRM) high dose and refuge strategy assumes resistance is recessive. Many susceptible moths (SS) are produced in refuge maize that mate with rare resistant (RR) moths. Mating of resistant (RR) and susceptible (SS) moths produces heterozygous (RS) moths that die when they feed on high-dose Bt maize. This strategy dilutes resistance genes and delays or prevents the evolution of resistance to Bt maize. © 2012 Nature Education All rights reserved.Nature Education

23 Farmers who plant crops with Bt trait(s) must also plant a refuge area - a block or strip of crops without the Bt gene.Bt Insects who feed on that crop remain susceptible to Bt technology. When they then mate with the rare insects that survive after feeding on Bt corn, they produce offspring that is susceptible to the technology. Farmers who plant crops with Bt trait(s) must also plant a refuge area - a block or strip of crops without the Bt gene.Bt Insects who feed on that crop remain susceptible to Bt technology. When they then mate with the rare insects that survive after feeding on Bt corn, they produce offspring that is susceptible to the technology. Avoiding/Delaying appearance of resistance

24 Refuge Configurations Farmers Can Use

25 The EPA requires a corn field that contains insect-protected (or Bt) crops with a single mode- of-action against corn rootworm to be planted with 20% non-Bt corn in corn-growing areas ( the U.S. Corn Belt ) and 50% non-Bt in cotton-growing areas ( the U.S. Cotton Belt ). New seed technologies that have multiple Bt genes, or modes-of-action, provide additional protection. This enabled the EPA to reduce the size of structured. The EPA requires a corn field that contains insect-protected (or Bt) crops with a single mode- of-action against corn rootworm to be planted with 20% non-Bt corn in corn-growing areas ( the U.S. Corn Belt ) and 50% non-Bt in cotton-growing areas ( the U.S. Cotton Belt ). New seed technologies that have multiple Bt genes, or modes-of-action, provide additional protection. This enabled the EPA to reduce the size of structured. Different Refuge Requirements

26 The right amount of refuge seed is included in the bag Farmers simply put the complete seed bag in the planter and plant both the Bt crop and the refuge The right amount of refuge seed is included in the bag Farmers simply put the complete seed bag in the planter and plant both the Bt crop and the refuge

27 For cotton growers, there was a lot of pressure from pests before the introduction of Bt cotton in Due to synthetic pesticide resistance, farmers were losing much of their cotton to tobacco budworms, cotton bollworms, and pink bollworms. For cotton growers, there was a lot of pressure from pests before the introduction of Bt cotton in Due to synthetic pesticide resistance, farmers were losing much of their cotton to tobacco budworms, cotton bollworms, and pink bollworms.

28 Tobacco Budworm, Heliothis virescens

29 Cotton Ballworm Helicoverpa armigera Cotton Ballworm Helicoverpa zea

30 The Pink Bollworm Pectinophora gossypiella

31 Green bolls (100/field) were sampled from the uppermost internodes within adjacent fields of Bt (Deltapine 33B) and non-Bt (Hyperformer HS 44) cotton experiencing severe pink bollworm pressure late in the growing season. Average top crop lint yield reductions ranging from 30 to 70% were observed in the uppermost bolls of the non-Bt cotton variety. Average top crop lint yield reductions ranging from 0 to 40% were observed in the uppermost bolls of the transgenic Bt cotton variety. Benefits of Bt Cotton China, 2007 Benefits of Bt Cotton China, 2007

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33 Y IELDS OF B T COTTON VERSUS CONVENTIONAL COTTON IN C HINA ( KG / HA ). דומה דומה ‑ גדלים נוספים גדלים נוספים

34 Pesticide use has been cut by at least half, a new study shows. The use of Bt cotton helps to avoid at least 2.4 million cases of pesticide poisoning in Indian farmers each year, saving US$14 million in annual health costs. ( The current study, published online in the journal Ecological Economics) India is now the world’s biggest producer of Bt cotton with an estimated 23.2 million acres planting in דומה דומה ‑ גדלים נוספים גדלים נוספים Benefits of Bt Cotton in India, 2011

35 Scientists have confirmed incidents of insects evolving resistance to Bt toxins in the field to date: Bt cotton in India (2010) and US (2008). Field monitoring in parts of Gujarat has discovered that the Bt crop is no longer effective against the pink bollworm pest there. Scientists have confirmed incidents of insects evolving resistance to Bt toxins in the field to date: Bt cotton in India (2010) and US (2008). Field monitoring in parts of Gujarat has discovered that the Bt crop is no longer effective against the pink bollworm pest there. Insects Evolving Resistance

36 A study concluded in India 2011, concluded: A decade of planting with GM cotton, or any GM crop with Bt genes could lead to total destruction of soil organisms, “leaving dead soil unable to produce food.” GM Cotton May Affect Biomass

37 Bacteria overall were reduced by 14 percent, while the total microbial biomass was reduced by 8.9 percent. Vital soil enzymes, which make nutrients available to plants, have also been drastically reduced. Acid phosphatase which contributes to the uptake of phosphates was lowered by 26.6 percent. Nitrogenase enzymes, which help fix nitrogen, were diminished by 22.6 percent. GM Cotton May Affect Biomass

38 Bt cotton adversely affected the farmers leading to suicides being committed, and loss of biodiversity. There are studies, which show that yields do not rise necessarily due to growing of Bt cotton. The quality of the cotton grown is poor in the case of Bt cotton. It provides little resistance to Pink bollworm. The economic advantage of growing Bt cotton is over-exaggerated. The seed companies are extracting huge royalties by selling the genetically modified seeds at higher prices to farmers. Bt Cotton Led Agri-revolution, 2009

39 European corn borer Ostrinia nubilalis

40 Southwestern Corn Borer, Diatraea grandiosella,

41 Corn Earworm Helicoverpa zea

42 Fall Armyworm Spodoptera exigua

43 Black Cutworm Peridroma saucia

44 Western corn rootworm ( Diabrotica virgifera )

45 The diamondback moth ( Plutella xylostella ), sometimes called cabbage moth

46 Refuge requirement Pests controlled or suppressed Trade name Bt geneCompany 5% non-Bt refuge in, or immediately adjacent to Bt field European and southwestern corn borers, corn earworm, fall armyworm and corn rootworms SmartStax CryIF + Cry34Ab1 + Cry35Ab1 + C0ry3Bb1 + Cry1A.105+ Cry2Ab Dow Chemical Co. + Monsanto 20% non-Bt refuge needed within 1/4 to 1/2 mile Corn borers, corn earworm, fall armyworm, black cutworm Agrisure Viptera 3110 VIP and CryIAb Syngenta Seeds Inc

47 Severe lodging caused by western corn rootworm larvae to Bt corn expressing the Cry3Bb1 protein (northwestern Illinois, August ). Resistance of Rootworm in Bt Cron

48 It is said that the Western corn rootworm ( Diabrotica virgifera ) causes one billion dollars worth of damage annually in the maize- growing areas of the USA. The soil-dwelling larvae of the beetle eat the aerial roots, which quickly die back. Older larvae then penetrate the heart of the root and from there move further into the maize plants. Many infested plants collapse before harvest as a result of the root damage.

49 If rootworms do become resistant to Bt corn, it “could become the most economically damaging example of insect resistance to a genetically modified crop in the U.S.,” said Bruce Tabashnik, an entomologist at the University of Arizona. “It’s a pest of great economic significance — a billion-dollar pest.”

50 F IELD -E VOLVED I NSECT R ESISTANCE TO B T C ROPS : A R EVIEW After more than a decade since initial commercialization of Bt crops, most target pest populations remain susceptible, field-evolved resistance has been documented in some populations of three noctuid moth species:  Spodoptera frugiperda (Armyworm), Bt corn,Puerto Rico,  Busseola fusca (stem borer) to Cry1Ab in Bt corn in South Africa,  Helicoverpa zea (Corn Earworm ) to Cry1Ac and Cry2Ab in Bt cotton in the southeastern United States. Factors delaying resistance include:  Recessive inheritance of resistance,  Abundant refuges of non- Bt host plants,  Two-toxin Bt crops deployed separately from one-toxin Bt crops. Journal of Economic Entomology- 2009

51 B T T OXINS Scientists have modified the molecular structure of two Bt toxins, Cry1Ab and Cry1Ac, in order to overcome resistance. The novel toxins, Cry1AbMod and Cry1AcMod, are effective against five resistant insect species, such as the diamondback moth, the cotton bollworm, and the European corn borer. Cry1AbMod and Cry1AcMod can be used alone or in combination with other Bt toxins for plant protection

52 Scientists have developed Bt toxins for the management of Bt resistance in European corn borer and other crop pests. New Bacteria Toxins Against Resistant Insect Pe sts

53 In addition to the endotoxins, B. thuringiensis also produces secreted insecticidal proteins during its vegetative growth stage, namely, vegetative insecticidal proteins (Vip). Vip toxins include two major groups : Vip1 and Vip2 The combination of Vip1 and Vip2 is highly insecticidal to an agriculturally important insect, the western corn rootworm ( Diabrotica virgifera ), but does not show any insecticidal activity for any lepidopteran insects B.t. VIP Toxins

54 V IP 3 TOXIN The first-identified Vip3 toxin, Vip3Aa1, is highly insecticidal to several major lepidopteran pests of maize and cotton, including the fall armyworm Spodoptera frugiperda and the cotton bollworm Helicoverpa zea, but shows no activity against the European corn borer Ostrinia nubilalis, a major pest of maize. Vip3 contributes to the overall toxicity of B. t strains

55 S TRATEGIES TO IMPROVE THE INSECTICIDAL ACTIVITY OF C RY TOXINS FROM B ACILLUS THURINGIENSIS (i) Chitinase that improves accessibility of the toxin to the epithelial membrane. (ii) Serine protease inhibitors that reduce degradation of Cry or of toxin-receptors. (iii) Introduction of intramolecular cleavage sites in the toxin that improves binding interaction. (iv) Introduction of more binding sites such as the CR12-MPE-peptide from cadherin receptor or the Cyt1A toxin. (v) Deletion of helix α-1 that induces toxin- oligomerization and skip cadherin interaction. Peptides Vol:

56 S TRATEGIES TO IMPROVE THE INSECTICIDAL ACTIVITY OF C RY TOXINS FROM B.T

57 Monsanto's GMO sweet corn is engineered to tolerate the herbicide Roundup, and to produce the insect- killing toxin Bt. These modifications have been shown to lead to some serious health problems in animals who eat them.

58 How can genetically modified (GM) corn and its attributed changes in agricultural practices affect the agro- ecosystem’s biodiversity and the economic status and social life of the farmers? Philippines 2013

59 GMO I MPACT ON H UMANITY Genetic engineering may disrupt the precise sequence of a food's genetic code. Disturbs the functions of neighboring genes, Can give rise to potentially toxic or allergenic molecules or even alter the nutritional value of food produced.

60 The Bt toxin used in GMO corn, was recently (2013), detected in the blood of pregnant women and their babies, with possibly harmful consequences.

61 Livestock, especially goats and cattle that eat GM corn leaves and stalks, become sickly, suffering from diarrhea. Carabaos and cows have been observed to lose weight and are sickly. In Caquilingan, Cordon, Isabela for example, five carabaos died in Farmers examined the carabaos’ stomachs, these were filled with undigested corn fodder. GMO Impact on livestock– Philippines 2013

62 A GMO crop, once released in the open, reproduces via pollination and interacts genetically with natural varieties of the same crop. A GMO crop produces ‘genetic contamination’. According to a study published in Nature, one of the world's leading scientific journals, Bt corn has contaminated indigenous varieties of corn tested in Oaxaca, Mexico. GMO May Cause Genetic Contamination

63 GMO brought into natural surroundings may have a toxic or lethal impact on other living organisms. Bt corn destroyed the larvae of the monarch butterfly. Many other natural plant and animal life may be impacted in the same way. GMO Impact on Biodiversity

64 Scarce vegetation, acidic soil, Silted rivers, only few fishes remain; Papaya fruits are deformed Soil is easily eroded especially during the rainy season. Stones protrude out from the soil and the soil turns red and clayish. Corn leaves turn violet. GMO Impact on Environment – Philippines 2013 Published 2013 by Magsasaka at Siyentipiko para sa Pag- unlad ng Agrikultura MASIPAG

65 The benefits of GMOs have been oversold by the companies, like Monsanto and Syngenta, that peddle them.

66 It has been shown, however, that insects are fast developing resistance to Bt as well as to herbicides, resulting in even more massive infestation by the new superbugs. No substantial evidence exists that GM crops yield more than conventional crops. What genetically engineered crops definitely do lead to is greater use of pesticide, which is harmful both to humans and the environment.

67 Public debates about transgenic crops should focus more on the health and environment al benefits which can be substantial.


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