Bacillus thuringiensis Cotton Bt Cotton

Download Bacillus thuringiensis Cotton Bt Cotton

Post on 30-Oct-2014

180 views

Category:

Documents

7 download

Embed Size (px)

DESCRIPTION

INTRODUCTION OBJECTIVE WHAT IS BT COTTON WHAT IS BT? HOW Bt Cotton WAS DEVELOP METHOD ADVANTAGES OF BT COTTON DISCUSSION (our last minute result, not perfect tho)

TRANSCRIPT

<p>UNIVERSITI TEKNOLOGI MARA NEGERI fill KAMPUS fill</p> <p>Bacillus thuringiensis Cotton MIC000 course name</p> <p>NAME OF PARTNERS: 1 2 3 4 5 DATE: 00/00/0000 LECTURER NAME: MISS GROUP: AS000 DIPLOMA IN fill FACULTY OF APPLIED SCIENCE 2010 2010 2010 2010 2010</p> <p>INTRODUCTION Bt Cotton is a genetically modified cotton crop that has one or two genes of a soil bacterium inserted into the seeds of cotton. Genes from Bacillus thuringensis is inserted to the plant. These genes allow the plants to produce toxins which specifically affect certain groups of insects. These genes allow the plants to produce toxins which specifically affect certain groups of insects. Bt cotton, or Bacillus Thuringiensis cotton, is used the same as any other cotton. The only difference is that it has a protein genetically added which is identical to that of B. thuringiensis bacteria which is toxic to many caterpillars, especially Lepidoptera species. Therefore it is an economically important "built-in" insecticide. Bt Cotton as containing a bacterium called Bacillus Thuringiensis (Bt). The spores of Bt produce crystal proteins which are toxic to many forms of insects, leading to its use as an</p> <p>insecticide. Bt is found throughout the world in a variety of soils in very small amounts producing thousands of different strains of Bt. Bt Cotton is a genetically engineered form of natural cotton. The main advantage of utilizing biotechnology in agriculture are the possibilities of increase in productivity through</p> <p>the use of newer varieties that possess properties such as resistance to pests, diseases, and other stressful conditions like drought, salinity, or water logging. Of these measures, imparting the property of insect (specific) resistance through the transfer of a gene from Bacillus Thuringiensis (Bt) into target plants by modern biotech methods is presently considered to be one of the most advanced applications of biotechnology.</p> <p>OBJECTIVE 1. To study the effects of transgenic cotton in the field. 2. To study the effectiveness of Bt cotton against the pink bollworm and other insects, its yield and cultural characteristics, insect resistance management, and how the cotton works in combination with other control measures. 3. To control the pest that harmed cotton. 4. To decrease the usage of chemical pesticides</p> <p>WHAT IS BT COTTON Bt Cotton is a genetically engineered form of natural cotton. The main advantage of utilizing biotechnology in agriculture are the possibilities of increase in productivity through the use of newer varieties that possess properties such as resistance to pests, diseases, and other stressful conditions like drought, salinity, or water logging. Bt Cotton is produced by inserting a synthetic version of a gene from the naturally occurring soil bacterium Bacillus thuringiensis, into cotton. The primary reason this is done is to induce the plant to produce its own Bt toxin to destroy the bollworm, a major cotton pest. The gene causes the production of Bt toxin in all parts of the cotton plant throughout its entire life span. When the bollworm ingests any part of the plant, the Bt cotton toxin pierces its small intestine and kills the insect.</p> <p>WHAT IS BT?The insect- disease- causing organism Bacillus thuringiensis (Bt) is a naturally occurring soil borne bacterium found worldwide. A unique feature is its production of crystal-like proteins that selectively kill specific groups of insects and other organisms. When the insect eats these Cryproteins, its own digestive enzymes activate the toxic form of the protein. Cryproteins bind to specific receptors on the intestinal walls and rupture midget cells. Susceptible insects stop feeding within a few hours after taking their first bite, and, if they have eaten enough toxins, die within 2 or 3 days. Different Bt strains produce different Cryproteins, and there are hundreds of known strains. Scientists have identified more than 60 types of Cryproteins that affect a wide variety of insects. Most Cryproteins are active against specific groups of in often create other problems, such as higher populations of beet armyworms and cotton aphids and an increased pesticide load in the environment. Frequent exposure of insect pests to insecticides results in the development of insecticide resistance, which reduces the overall effectiveness of available insecticides, increases crop losses, and leads to higher pest control costs and lower farm profits. The severity of tobacco budworm and bollworm infestations and resistance to synthetic insect Bollworm larva feeding in bollcides vary across the Cotton Belt, both between and within the states. Because of this variation and the price of the technology, not all areas of the Cotton Belt are able to economically justify the use of Bt cotton. However, where insect infestations are severe, Bt cotton offers a new management tool for producers, helps ensure against yield loss in the presence of heavy infestations of insecticide-resistant tobacco budworms, and aids in reducing bollworm damage from Insects, such as the larvae of certain kinds of flies, beetles, and moths. For example, Colorado potato beetle larvae are affected by Cry3A proteins, Cry1Ac is used against tobacco budworms; and European corn borers can be killed with Cry1Ab, Cry1F, Cry1Ac, and Cry9c proteins. Other Cryproteins are active against mosquito larvae, flies, or even nematodes. Some Cry-proteins have been used for more than 30 years in various liquid and granular formulations of natural Bt insecticides, mainly to control caterpillars on a variety of crops. The Bt cotton varieties presently used against tobacco budworms, bollworms, and certain other caterpillars produce the Cry1Ac protein.</p> <p>HOW Bt Cotton WAS DEVELOP About ten years ago, Monsanto scientists inserted a toxin gene from the bacterium called Bt (which is the nickname for Bacillus thuringiensis) into cotton plants to create a caterpillar-resistant variety. The gene is DNA that carries the instructions for producing a toxic protein. The toxin kills caterpillars by paralyzing their guts when they eat it. Plants with the Bt toxin gene produce their own toxin and thus can kill caterpillars throughout the season without being sprayed with insecticide. Because the toxin is lethal to caterpillars, but harmless to other organisms, it is safe for the public and the environment. Bt cotton produces an insecticidal protein (Cry1Ac) from the naturally occurring soil bacterium Bacillus thuringiensis (Bt) that protects the cotton plant from certain lepidopteran (caterpillar) insect pests. Coker 312 cotton was transformed to express the Cry1Ac gene from Bt, resulting in cotton plants that were resistant to attack from major lepidopteran pests. Bacillus thuringiensis (or Bt) is a Grampositive, soil-dwelling bacterium, commonly used as a pesticides the the Cry toxin may be extracted and used as a pesticide. 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 feaces, insect rich environments, flour mills and grain storage facilities During sporulation, many Bt strains produce crystal proteins (proteinaceous inclusions), called -endotoxins, that have insecticidal action. This has led to their use as insecticides, and more recently to genetically modified crops using Bt genes. Many crystal-producing Bt strains, though, do not have insecticidal properties. Biotechnologists created Bt cotton by inserting selected exotic DNA, from a Bt bacterium, into the cotton plants own DNA. DNA is the genetic material that controls expression of a plants or an animals traits. Following the insertion of modified Bt DNA into the cotton plants DNA, seed companies moved the Cry-protein trait into high performance cotton varieties by traditional plant breeding methods. Agronomic qualities for yield, harvest ability, fiber quality, and other important characteristics were preserved at the same time the Cryprotein gene was added to commercial varieties.</p> <p>METHOD</p> <p>Genetically engineered products The concept of genetically engineered products has been in existence for quite long before we knew them to exist. For instance insulin gene derived from the intestines of pigs is inserted into bacteria. This bacterium grows and makes insulin, which is purified from the bacterial culture and used medically. The same is true of the thyroid hormone, which, until recently, was derived only from animals. Once again, genetic engineering enabled this hormone to be cultured in the bacteria. How was Bt Cotton produced? So what is a GM crop? Genetic Modification of crops is one method of biotechnology - allowing individual characters (genes or traits) to be transferred into crop plants.</p> <p>Genetic Improvement through Biotechnology 1. Identify genes of Bacillus thuringiensis (Bt) with desired traits 2. Make copies of genes 3. Transfer to target plant tissue, cotton 4. Regenerate plant 5. Analysis and safety testing was done 6. Varieties of toxin are produced by using back-cross technique 7. Field testing to confirm its successfulness 8. Approval and commercialism</p> <p>The three primary components of the genetic package inserted into cotton DNA include:</p> <p>Protein gene The Bt gene, modified for improved expression in cotton, enables the cotton plant to produce Cry-protein. The first varieties of Bt cotton produced in the United States contained one Cry-protein geneCry1Ac. Other varieties contain a stacked gene complex, for example one gene for insect control (Cry1Ac) and one gene to protect the cotton from application of the herbicide glyphosate. Future cotton varieties may include these genes, other genes that allow the plant to produce different Cry-proteins, or insecticidal proteins from sources other than Bt. There are many possible combinations for crop improvement traits.</p> <p>Promoter A promoter is a DNA segment that controls the amount of Cry-protein produced and the plant parts where it is produced. Some promoters limit protein production to specific parts of the plant, such as leaves, green tissue, or pollen. Others, including those used in Bt cotton and certain Bt corn varieties, cause the plant to produce Cry-protein throughout the plant. Promoters can also be used to turn on and turn off protein production. Current varieties of Bt cotton produce some Bt protein throughout the growing season.</p> <p>Genetic marker A genetic marker allows researchers to identify successful insertion of a gene into the plants DNA. It also assists plant breeders in identifying and developing new cotton lines with the Bt gene. A common marker is an herbicide tolerance gene linked to the Bt gene. Following a transformation attempt to place the Bt and marker gene into the plants DNA, plants are treated with herbicide. Plants that were successfully transformed have the Bt gene and the herbicide resistance gene and will survive herbicide treatment; plants without the marker gene, and hence without the linked Bt gene, will be killed by the herbicide. This genetic packagea Bt gene plus a promoter and markercan be inserted into cotton plant DNA through a variety of plant transformation techniques.</p> <p>ADVANTAGES OF BT COTTON 1. Economic and Production Benefits a. Bt cotton provided US farmers with an average net income increase of $20 and increased the total net value of US cotton production by $103 million in 2001. b. China, net revenue increases have ranged from $357/hectare to $549/hectare in the three years studied when one compares Bt cotton with non-Bt cotton. c. In South Africa, smallholder farmers in the Makhathini region raised their yields and reduced their application costs, netting an economic advantage for Bt cotton growers of about $25-51/hectare.</p> <p>2. Environmental Benefits. a. Bt cotton can substantially reduce the number of pesticide sprayings, which can provide significant environmental benefits. b. Bt cotton adoption can provide secondary positive environmental impacts such as i. Saving on raw materials needed to manufacture chemical insecticides. ii. Conserving fuel oil required to manufacture, distribute, and apply such insecticides. iii. Eliminating the need to use and dispose of insecticide containers.</p> <p>3. Does not affect beneficial insects such as honey bees, lady beetles, spiders, big eyed bugs, pirate bugs, and parasitic wasps.</p> <p>4. Benefits for Smallholder Farmers a. At the macroeconomic level, the increased productivity can stabilize production and reduce risks for lenders. b. At the farm level, improvements in the insect control system being used can positively impact the quality of life for farmers and their families by increasing incomes, reducing insecticide sprayings, and offering savings in time. c. Increased the yield of Bt cotton and farmer income.</p> <p>DISCUSSION The only successful approach to engineering crops for insect tolerance has been the addition of Bt toxin, a family of toxins originally derived from soil bacteria. The Bt toxin contained by the Bt crops is no different from other chemical pesticides, but causes much less damage to the environment. These toxins are effective against a variety of economically important crop pests but pose no hazard to non-target organisms like mammals and fish. Three Bt crops are now commercially available: corn, cotton, and potato. Bt toxin is insecticidal only when eaten by the larvae of specific host insects. Unlike Bt commercial formulations that must be targeted against a range of larvalinstars through optimally timed applications to cover the larval feeding sites, transgenic Bt cotton has a consistent built-in delivery system present in plant tissues where newly hatched larvae normally feed. High levels of resistance to ACB depend upon an adequate titer of Bt protein being expressed in these tissues. Neonates of ACB prefer specific feeding sites in cotton, and initially establish in the terminals, top new leaves, floral buds, match-head squares, and white flowers. Our results indicate that all of these tissues expressed sufficient Bt protein to provide significant protection from ACB feeding. These results also show, however, that survival increased as the plants aged, especially for the GK-2 cultivar. This phenomenon was also observed for the cotton bollworms H. armigera and H. zea. Increased survival in each species may be attributed to the decline in protein expression as the growing season progresses. Historically, ACB has been a sporadic pest of cotton. Recently, however, spring planting of several ACB hosts, especially corn, have been widely reduced in the cotton planting areas. This change in the cropping ecosystem has resulted in a higher incidence of ACB on cotton since the late 1980s. The efficacy of transgenic Bt cotton, expressing Cry1Ac or Cry1A proteins, to several major cotton pests such as the tobacco budworm, Heliothis virescens (Fabricius), cotton bollworm, H. zea, H. armigera, fall armyworm, S...</p>

Recommended

View more >