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Tanaman Transgenik. Fifi Fitriyah Masduki 12 November 2010. Transgenics are a Biotechnology Product. Biotechnology - General Definition. The application of technology to improve a biological organism. Biotechnology - Detailed Definition.
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TanamanTransgenik Fifi Fitriyah Masduki 12 November 2010
Transgenics are a Biotechnology Product Biotechnology - General Definition The application of technology to improve a biological organism Biotechnology - Detailed Definition The application of the technology to improve the biological function of an organism by adding genes from another organisms Sumber : Phil McClean, NDSU, 2003
What About the Term Genetic Engineering? Genetic engineering is the basic tool set of biotechnology Genetic engineering involves: • Isolating genes • Modifying genes so they function better • Preparing genes to be inserted into a new species • Developing transgenes 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 taste Enhance Nutrition
Molecular Farming Why create transgenic plant? TembakauvsE. 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 cropsanattractive alternative
IPP Geranylgeranyl diphosphate Phytoene synthase Phytoene Problem: Rice lacks these enzymes Phytoene desaturase ξ-carotene desaturase Lycopene Lycopene-beta-cyclase Normal Vitamin A “Deficient” Rice -carotene (vitamin A precursor) -Carotene Pathway Problem in Plants
IPP Geranylgeranyl diphosphate Phytoene synthase Phytoene Vitamin A Pathway is complete and functional Phytoene desaturase ξ-carotene desaturase Lycopene Lycopene-beta-cyclase -carotene (vitamin A precursor) Golden Rice The Golden Rice Solution -Carotene Pathway Genes Added Daffodil gene Single bacterial gene; performs both functions Daffodil gene
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
Shikimic acid + Phosphoenol pyruvate Plant EPSP synthase 3-Enolpyruvyl shikimic acid-5-phosphate (EPSP) Aromatic amino acids Roundup Sensitive Plants + Glyphosate X X Without amino acids, plant dies X X
Roundup Resistant Plants Shikimic acid + Phosphoenol pyruvate + Glyphosate RoundUp has no effect; enzyme is resistant to herbicide Bacterial EPSP synthase 3-enolpyruvyl shikimic acid-5-phosphate (EPSP) With amino acids, plant lives Aromatic amino acids
Insect resistant plant story • Insect resistant cotton – Bt toxin kills the • cotton boll worm • transgene = Bt protein Source: USDA • Insect resistant corn – Bt toxin kills the • European corn borer • transgene = Bt protein Normal Transgenic
Introducing the Gene or Developing Transgenics Steps 1. Create transformation cassette 2. Introduce and select for transformants
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 Cassettes Contains
Tissue must be capable of developing into normal plants • Leaf, germinating seed, immature embryos • Develop shoots • Root the shoots Transformation Steps Prepare tissue for transformation Introduce DNA • Agrobacterium or gene gun Culture plant tissue Field test the plants • Multiple sites, multiple years
Agrobacterium Tissue culture required to generate transgenic plants • Gene Gun Delivering the Gene to the Plant • Transformation cassettes are developed in the lab • They are then introduced into a plant • Two major delivery methods
Chloroplast vs Nuclear WT Flowers + transgenic pollen Transgenic Flowers + WT pollen
Resistance shoot Heteroplasmy Homoplasmy Chloroplast transformation (Source: Bock and Khan 2004)
Edible Vaccines Transgenic 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: • Diarrhea • Hepatitis B • Measles
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 Basis for Plant Tissue Culture