650 likes | 664 Views
The u201csharingu201d of DNA among living forms is well<br>documented as a natural phenomenon.<br>uf0ae For thousands of years, genes have moved<br>from one organism to another.<br>uf0ae For example, Agrobacterium tumefaciens, a soil<br>a bacterium is known as 'nature's own genetic<br>engineer', has the natural ability to genetically<br>engineer plants.<br>Insertion of copies of a gene into living cells in order to<br>induce synthes is of the gene's product.<br>Why Gene transfer?<br>u2756 To add a desired trait to a crop, a foreign gene<br>(transgene) encoding the trait must be inserted into<br>plant cells, along with a u201ccassetteu201d of additional<br>genetic material. The cassette includes a DNA<br>sequence called a u201cpromoter,u201d which determines<br>where and when the foreign.<br>u2756 Gene is expressed in the host, and a u201cmarker geneu201d<br>that allows breeders to determine which plants<br>contain the inserted gene by screening or selection.
E N D
METHODS OF GENE TRANSFERIN PLANTS Dr. Thirunahari Ugandhar Assistant Professor in Botany Govt Degree College Mahabubabad
Sufficient, Nutritionally Adequate & Culturally Acceptable Food for an Active, Healthy Life. 5/20/2020 3
Introduction The “sharing” of DNA among living forms is well documented as a natural phenomenon. For thousands of years, genes have moved from one organism to another. For example, Agrobacterium tumefaciens, a soil bacterium known as 'nature's own genetic engineer', has the natural ability to genetically engineer plants.
Conventional breeding Plants Tissue culture Genetic engineering 5/20/2020 6
What What is is Gene Genetransfer transfer Insertion of copies of a gene into living cells in order to induce synthes is of the gene's product. Why Genetransfer? ❖ To add a desired trait to a crop, a foreign gene (transgene) encoding the trait must be inserted into plant cells, along with a “cassette” of genetic material. The cassette includes a DNA sequence called a “promoter,” which determines where and when the foreign. ❖ Gene is expressed in the host, and a “marker gene” that allows breeders to determine which plants contain the inserted gene by screening or selection. additional
Why genetically Engineer Plants? ➢To improve the agricultural, horticultural or ornamental value of a crop plant. ➢To serve as a living bioreactor for the production of economically proteins or metabolites ➢To provide a renewable source of energy To provide a powerful means for studying the action of genes (and gene products) during development and other biological processes important
Desired Traits Pest resistance Herbicide tolerance Viral resistance Drought resistance Increased nutritional value Improved Fruit Altered ripening
Genetic Engineering Genetic engineering, also called genetic modification, is the direct manipulation of an organism's Genome using Biotechnology New DNA may be inserted in the host genome by first isolating and copying the genetic material of interest using Molecular Cloning methods to generate a DNA sequence, or by synthesizing the DNA, and then inserting this construct into the host organism.
Engineer An Engineer is a Professional Practitioner of Engineering, concerned Scientific Knowledge and ingenuity to develop solutions for technical problems. Engineers design materials, structures, and systems while considering imposed by practicality, regulation, safety, and cost. The word Engineer is derived from the Latin roots ingeniare ("to contrive, devise") and ingenium ("cleverness") with applying the limitations
TRANSGENIC PLANTS ✓The process of introducing new genes into plants to produce new traits is called Plant Genetic Engineering. ✓The product of this process is called Transgenic Plants. Transgenic plants contain a gene or genes which have been artificially inserted. The inserted genes are known as transgenic. 5/20/2020 12
TRANSGENIC PLANTS – AN INTRODUCTION ❖ Transformation – The process of obtaining transgenic plants. ❖ Transgenic plant – a plant with a foreign gene (or genes) from another plant/animal that is incorporated into its chromosome ❖ Marc Van Montagu and Jeff Schell, discovered the gene transfer mechanism between which resulted in the development of methods to alter the bacterium into an efficient delivery system for genetic engineering in plants. ❖ Most common genes (and traits) in transgenic or biotech crops herbicide resistance Insecticide resistance, Bt genes in field corn (maize) virus-resistance (coat-protein) genes Agrobacterium and plants,
WHY HAVE GM CROPS? Growing Human Population Loss of Farmable Land Remediation of Soil Enrich Nutrient Content Transgenic Wild-type
Plant Transformation Methods In planta Chemical Biological Physical A. Tumefaciens A. Rhizogenes Microinjection Pressure Biolistics - gene gun/ particle bombardment Electroporation Microinjection Silica/carbon fibers Lazer mediated SAT PEG DEAE-dextran Calcium phosphate Artificial lipids Proteins Dendrimers Virus-mediated 5/20/2020 15
Genetic Transformation • PLANTS - PHYSICAL METHODS • Microinjection • Electroporation • Biolistics - gene gun • Silica/carbon fibers • Lazer mediated • SAT 5/20/2020 18
1. MICROINJECTION 5/20/2020 19
2. Electroporation This electroporator is for low-current applications such as those using small electrodes 5/20/2020 20
3. Biolistic / Gene Gun 5/20/2020 21
Streptothricin Acetyl Transferase (SAT) T R A N S F O R M A T I O N 5/20/2020 25
Chemical Gene Transfer 1. PEG 2. DEAE-dextran 3. Calcium phosphate 4. Artificial lipids 5. Proteins 6. Dendrimers
Biological Transformation ❑ Agrobacterium tumefaciens & ❑ Agrobacterium rhizogenes 5/20/2020 32
5/20/2020 33
BIOLOGICAL TRANSFORMATION Possible plant compounds, that initiate Agrobacterium to infect plant cells. Acetosyringone, ferulic acid, gallic acid, Hydroxybenzoic acid, pyrogallic acid, vanillin etc. In monocot – not efficient Transformation frequencey – very less 5/20/2020 34
5/20/2020 35
Agrobacterium Agrobacterium (disease symptomology and host range) A. radiobacter - “avirulent” species A. tumefaciens - crown gall disease A. rhizogenes - hairy root disease A. rubi - cane gall disease A. vitis - galls on grape and a few other plant species Otten et al., 1984 5/20/2020 36
Cellular process of Agrobacterium–host interaction Tzvi Tzfira and Vitaly Citovsky, 2002, Trends in Cell Biol. 12(3), 121 5/20/2020 37
5/20/2020 38
5/20/2020 39
5/20/2020 40
Plant Transformation Methods Virus-mediated gene transfer (Plant viruses as vectors) Caulimo viruses – ds DNA – CaMV Gemini viruses - 2ss DNA – maize streak virus RNA plant viruses - TMV 5/20/2020 41
POLYMERASE CHAIN REACTION PCR (polymerase chain reaction) is a method to analyze a short sequence of DNA (or RNA) even in samples containing only minute quantities of DNA or RNA. Kary Banks Mullis (Born December 28, 1944) is a Nobel Prize -winning American Biochemist, author, and lecturer. In recognition of his improvement of the Polymerase Chain Reaction (PCR) technique
PCR Animation Denaturation: DNA melts Annealing: Primers bind Extension: DNA is replicated
Recombinant DNA & Plasmids Combining genes from different sources and/or species Circular DNA from bacteria = plasmids Target DNA recombined in plasmid Bacteria rapidly reproduces many clones
Production of transgenic plants Isolate and clone gene of interest Add DNA segments to initiate or enhance gene expression Add selectable markers Introduce gene construct into plant cells (transformation) Select transformed cells or tissues Regenerate whole plants 5/20/2020 47
PLANT TRANSFORMATION • Plants are the easiest of higher organisms to transform • Both physical and biological methods exist for transformation • Until recently, only transgenic organisms in wide public release were plants 5/20/2020 48
Which foods contain GM Product? India Approval for GM food crops •Corn •Soy •Papaya •Canola •Potato •Chicory •Rice •Squash •Sugarbeet •Tomatoes Approval does not necessarily mean these crops are distributed Database of GM crops: