BT COTTON

Bacillus thuringiensis cotton

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 such as caterpillar, 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

OBJECTIVE

• genetically engineered form of natural cotton• produced by inserting a synthetic version of a gene from

the naturally occurring soil bacterium Bacillus thuringiensis, into cotton

• to induce the plant to produce its own Bt toxin to destroy the bollworm, a major cotton pest

• toxin pierces its small intestine and kills the insect• genes of a soil bacterium (Bacillus thuringensis) inserted

into the seeds of cotton• produce crystal proteins which are toxic to many forms

of insects, leading to its use as an insecticide

WHAT IS BT COTTON

• insect- disease- causing organism Bacillus thuringiensis (Bt)

• selectively kill specific groups of insects and other organisms

• 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 midgut cells

• hundreds of known strains; different Bt strains produce different Cryproteins

WHAT IS BT

• Bt. Cotton was culture to prevent and controlling the Bt. Cotton plant that infection by ACB(Asian Corn Borer ) and Ball worm

• ten years ago, Monsanto scientists inserted a toxin gene from the bacterium called Bt into cotton plants to create a caterpillar-resistant variety

• the toxin kills caterpillars by paralyzing their guts when they eat it

• toxin is lethal to caterpillars, but harmless to other organisms, it is safe for the public and the environment

• Cry toxin may be extracted and used as a pesticide• Bt 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

HOW BT COTTON WAS DEVELOP

• Identify gene with desired trait• Make copies of the gene• Transfer to plant tissue • Regenerates plant• Analysis and safety testing • Back cross to produce varies• Field testing• Approval and commercialism

METHOD

GENE TRANSFER

(Of Bacillus pyorengenesis)

(cotton)

Protein gene. • enables the cotton plant to produce Cry-protein• first varieties of Bt cotton produced in the United States

contained one Cry-protein gene—Cry1Ac• gene for insect control (Cry1Ac) • gene to protect the cotton from application of the

herbicide glyphosate. • genes that allow the plant to produce different Cry-

proteins• many possible combinations for crop improvement traits

INSERTED INTO COTTON DNA

Promoter. • 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• cause the plant to produce Cry-protein throughout the

plant• can turn on and turn off protein production

INSERTED INTO COTTON DNA

Genetic marker. • allows researchers to identify successful insertion of a

gene into the plant’s DNA• assists plant breeders in identifying and developing new

cotton lines with the Bt gene• common marker is an herbicide tolerance gene linked to

the Bt gene• 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

INSERTED INTO COTTON DNA

• higher populations of beet armyworms and cotton aphids (bt cotton only kill caterpillar, bullworm)

• increased pesticide load in the environment (genes allow the plants to produce toxins)

• Increase other pest (doubled the level of ladybirds, lacewings and spiders)

• increases crop losses (only kill specific insect but harmless to other organism)

• leads to higher pest control costs and lower farm profits (this method is expensive, and yearly investigation must be done to make sure no resistance to this toxin in the target pest) (extra expense of GM seeds)

PROBLEMS

• helps ensure against yield loss in the presence of heavy infestations (save massive number of crop)

• aids in reducing bollworm damage, a type of cotton pest• economic and production benefits (raw materials, pesticide

container)

• reduce the number of pesticide sprayings, which can provide significant environmental benefits (which may harm environment)

• not affect beneficial insects such as honey bees

BENEFIT

COTTON BOLLWORM

PINK BOLLWORM

BACILLUS THURINGIENSIS