Tanaman Transgenik

Tanaman TransgenikFifi Fitriyah Masduki12 November 2010

Transgenics are a Biotechnology Product

Sumber : Phil McClean, NDSU, 2003

Biotechnology - General DefinitionThe application of technology to improve a biological organism

Biotechnology - Detailed DefinitionThe application of the technology to improve the biological function of an organism by adding genes from another organisms

What About the TermGenetic Engineering?

Genetic engineering involves:

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

Sumber : Phil McClean, NDSU, 2003

What is a transgenic?

Transgene – the genetically engineered gene added to a species

Transgenic – an organism containing a transgene introduced by technological (not breeding) methods

GMO - an organism that expresses traits that result from the introduction of foreign DNA

Originally a term equivalent to transgenic organism

Why create transgenic plant?

Increase yield

Enhance Nutrition

Enhance taste

Why create transgenic plant?

Molecular Farming

Tembakau vs E. coli

• 1 tobacco plant = million seeds• The leaves of 1 tobacco plant produce more recombinant protein than a 300-liter fermenter in E. coli• It cost about 50x more to produce 1kg of a recombinat protein in E. coli than in trangenic plants

The Golden Rice Story

• Vitamin A deficiency is a major health problem

• Causes blindness• Influences severity of diarrhea, measles

• >100 million children suffer from the problem

• For many countries, the infrastructure doesn’t exist to deliver vitamin pills

• Improved vitamin A content in widely consumed cropsan attractive alternative

-Carotene Pathway Problem in Plants

IPP

Geranylgeranyl diphosphate

Phytoene

Lycopene

-carotene(vitamin A precursor)

Phytoene synthase

Phytoene desaturase

Lycopene-beta-cyclase

ξ-carotene desaturase

Problem:Rice lacks

these enzymes

NormalVitamin A

“Deficient”Rice

The Golden Rice Solution

IPP

Geranylgeranyl diphosphate

Phytoene

Lycopene

-carotene(vitamin A precursor)

Phytoene synthase

Phytoene desaturase

Lycopene-beta-cyclase

ξ-carotene desaturase

Daffodil gene

Single bacterial gene;performs both functions

Daffodil gene

-Carotene Pathway Genes Added

Vitamin APathway

is completeand functional

GoldenRice

The Roundup Ready Story

• Glyphosate is a broad-spectrum herbicide

• Active ingredient in Roundup herbicide • Kills all plants it come in contact with• Inhibits a key enzyme (EPSP synthase) in an amino acid pathway

• Plants die because they lack the key amino acids

• A resistant EPSP synthase gene allows crops to survive spraying

+ Glyphosate

X

Roundup Sensitive Plants

X

X

Shikimic acid + Phosphoenol pyruvate

3-Enolpyruvyl shikimic acid-5-phosphate(EPSP)

Plant EPSP synthase

Aromaticamino acids

Without amino acids, plant dies

X

BacterialEPSP synthase

Shikimic acid + Phosphoenol pyruvate

3-enolpyruvyl shikimic acid-5-phosphate(EPSP)

Aromaticamino acids

Roundup Resistant Plants

+ Glyphosate

With amino acids, plant lives

RoundUp has no effect;enzyme is resistant to herbicide

Insect resistant plant story

Source: USDA

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

Normal Transgenic

Introducing the Geneor

Developing Transgenics

Steps

1. Create transformation cassette

2. Introduce and select for transformants

Transformation Cassettes

Contains

1. Gene of interest

• The coding region and its controlling elements

2. Selectable marker

• Distinguishes transformed/untransformed plants

3. Insertion sequences

• Aids Agrobacterium insertion

Transformation Steps

Prepare tissue for transformation

Introduce DNA

Culture plant tissue

• Develop shoots• Root the shoots

Field test the plants

• Leaf, germinating seed, immature embryos

• Tissue must be capable of developing into normal plants

• Agrobacterium or gene gun

• Multiple sites, multiple years

• Transformation cassettes are developed in the lab

• They are then introduced into a plant

• Two major delivery methods

Delivering the Geneto the Plant

• Agrobacterium

• Gene GunTissue culturerequired to generatetransgenic plants

Genome organization in plant

Chloroplast vs Nuclear

Chloroplast vs Nuclear

Chloroplast vs Nuclear

Chloroplast vs Nuclear

Chloroplast vs Nuclear

WT Flowers + transgenic pollen Transgenic Flowers + WT pollen

Chloroplast transformation

• Resistance shoot

• Heteroplasmy

• Homoplasmy

(Source: Bock and Khan 2004)

Edible VaccinesTransgenic Plants Serving Human Health Needs

• 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:

DiarrheaHepatitis BMeasles

• .. Thanks for your attention!!

Basic Science Purpose

Basis for Plant Tissue Culture• Two Hormones Affect Plant Differentiation:– Auxin: Stimulates Root Development– Cytokinin: Stimulates Shoot Development

• Generally, the ratio of these two hormones can determine plant development:– Auxin ↓Cytokinin = Root Development– Cytokinin ↓Auxin = Shoot Development– Auxin = Cytokinin = Callus Development