By Usman Arshad

Biotechnology is

The application of the technology to improve

the biological function of an organism

by

adding genes from another organisms

Transgenics

Isolating genes

Modifying genes so they function better

Preparing genes to be inserted into a new species

Developing transgenes

Genetic engineering is the basic tool set of biotechnology

Genetic engineering involves:

Transgenic – an organism containing a

transgene introduced by technological (not

breeding) methods

Concept Based on the Term Transgene

Transgene – the genetically engineered gene added to a species

To develop the organisms that express a “novel” trait

not normally found in the species

Extended shelf-life tomato (Flavr-Savr)

Herbicide resistant soybean (Roundup Ready)

1. Study gene function and regulation2. Generate new organismic tools for other fields of

research.3. Cure genetic diseases.4. Improve agriculture and related raw materials. 5. Generate new systems or sources for

bioengineered drugs (e.g., use plants instead of animals or bacteria).

Insect resistant cotton – Bt toxin kills the

cotton boll worm

• transgene = Bt protein

Insect resistant corn – Bt toxin kills the

European corn borer

• transgene = Bt protein

Herbicide resistant crops

Now: soybean, corn, canola

Coming: sugarbeet, lettuce, strawberry

alfalfa, potato, wheat

• transgene = phosphinothricin-N-

acetyltransferase

Virus resistance - papya resistant to

papaya ringspot virus

• transgene = virus coat protein

Biotech chymosin; the enzyme used

to curdle milk products

• transgene = genetically engineered enzyme

bST; bovin somatotropin; used to increase

milk production

• transgene = genetically engineered enzyme

Sunflower – white mold resistance

transgene = oxalate oxidase from wheat

Golden Rice – increased Vitamin A content

(but not without controversy)

transgene = three pathway enzymes

Turfgrass – herbicide resistance;

slower growing --- reduced mowing

Bio Steel – spider silk expressed in goats; used to

make soft-body bullet proof vests (Nexia)

• Works like any vaccine

• A transgenic plant with a pathogen protein gene is developed

• Potato, banana, and tomato are targets

• Humans eat the plant

• The body produces antibodies against pathogen protein

• Humans are “immunized” against the pathogen

• Examples:

Diarrhea

Hepatitis B

Measles

Steps1. Create transformation cassette

2. Introduce and select for transformants

Contains1. Gene of interest

The coding region and its controlling elements

2. Selectable marker

Distinguishes transformed/untransformed plants

3. Insertion sequences

Aids Agrobacterium insertion

Prepare tissue for transformation Tissue must be capable of developing into normal plants

• Leaf, germinating seed, immature embryos

Introduce DNA Agrobacterium or gene gun

Culture plant tissue Develop shoots

Root the shoots

Field test the plants Multiple sites, multiple years

Transformation cassettes are developed in the lab

They are then introduced into a plant

Two major delivery methods

Tissue culturerequired to generatetransgenic plants

• Agrobacterium

• Gene Gun

Herbicide Resistance

Transgenics

Non-transgenics

Consumer acceptence Flavr Savr tomatoes----poor quality

Bt cotton

Rice

Important cash crop for Pakistan known as

“White Gold”

Contribute to 8.2 percent of the value added in

agriculture and about 3.2 percent to GDP

Fourth-largest cotton producer and the third

largest exporter of raw cotton

High price of agriculture inputs

Higher intensity of insects and pests attack,

Shortage of good quality and varieties of seeds,

Water deficiency

Lack of advance technologies,

Lack of awareness and agro-professionalism,

Adulterations in pesticides, fertilizers and seeds

Two major types of pests are damaging our cotton

crops

◦ Sucking

◦ Chewing

Easy to cure the sucking pests but

difficult to cure the chewing ones.

Bollworms known as “Sundies”

Cause major devastations

So overall both quality of lint and production of

cotton have declined substantially

Bt gene introduction

Bacillus thuringiensis---bacterium that is pathogenic

for a number of insect pests

Lethal due to protein toxin it produces

If that gene is introduced in plant genome then its

expression provides protection from pests.

Bt cotton was widely planted first time in 1996 on large scale

In Pakistan, PAEC in 1997

In 2005 different varieties are introduced

◦ IR-FH-901

◦ IR-NIBGE-2

◦ IR-CIM-448 and

◦ IR-CIM-443

Bt Rice and Corn are under trilas in

china

For the resistance of bacterial leaf blight.

Rice varieties transgened

◦ Basmati -370

◦ DR - 82

◦ IR – 6

Gene:-

Xa21

Done by an Agrobacterium mediated transformation.

All PCR positive transgenic plants

◦ DR – 82

◦ Basmati - 370

were resistant with lesion areas less than 5% of

the inoculated leaf area

Genetically Modified (GM) food is as safe or even

safer than conventionally produced food

GM foods represent a very minor, precise and known

change

GM foods are subject to intense pre-market testing

GM foods are subject to stringent regulatory oversight