genetically modified organisms image: www.ars.usda.gov
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Genetically Modified OrganismsImage: www.ars.usda.gov
GMOs: Genetically Modified Organism
Any organism that has had its genetic material changed or manipulated in some way, usually as a result of human intervention.
This is the ancestor of what crop?Image: www.life.uiuc.eduImage: www.aggie-horticulture.tamu.edu
Strawberries with fish genes?Anti-freeze proteins in strawberry and tomato plants
Increase size (yield) of fruit or grain Height of plants (taller OR shorter) Flowering time to increase the number of crops in a year (rice) Drought or cold tolerance Appearance for ornamentalsTraditional breeding is limited to available genetic material in closely related speciesTrait targets of traditional plant breedingImage: www.dlc.fiImage: www.news.cornell.eduImage: http://faculty.etsu.edu/mcdoweltImage: www.jacksonandperkins.com
Traits for genetically engineered organismsIf there is a gene out there, it can be used, regardless of the source. Increase nutrient content (example: Golden Rice) Delay ripening of tomatoes for better shipping (example: Flavr-savr) Resistance to naturally occurring pests (example: Bt cotton) Resistance to otherwise harmful herbicides (example: RoundUp Ready soybeans)
GMO LabellingCurrently, only two products on the market are labeled for altered nutrient content:High laurate canola high oleic soybeanhttp://www.carleton.ca/catalyst/2005/s9.html
Agrobacterium tumefaciens: transfer of DNA into plants Naturally occurring soil bacterium that causes crown gall disease Bacteria contains the Ti (tumor-inducing) vector- a plasmid we can manipulate!
Ti vector: modified for genetic engineering Remove the tumor-inducing genes
Replace with gene of interest and promoter
Anything between the R and L border will be transferred.
Bacteria called Bacillus thuringiensis makes a protein with a crystal structure
The protein, when eaten by lepidoptera (caterpillars), sticks to the gut wall of the insect
Causes starvation and the dissolving of the internal organs
Purified protein has been used by organic farmers for years as a spray (is this a pesticide or herbicide?)Images: www.deh.gov.auBt: example of genetic modification
GMOs in the MarketAt least 70% of processed foods contain genetically modified ingredients: Corn- in packaged foods (corn syrup, corn starch, etc.) Cotton- Cotton isnt just clothing:cottonseed oil is present in many food items Soy -in packaged foods and animal feed Canola- the healthy oil
Genetically modified foods: Others Papayas
and more...While these have been modified and approved, you are most likely not eating theseImage: www.ebfarm.comImage: www.seedexseed.com
Modifications currently approvedHerbicide tolerance (soy, cotton, corn, radicchio, sugarbeet, flax, rice, bentgrass, wheat, alfalfa)Pesticide production (cotton, corn, potato, tomato)Disease resistance (papaya, squash, potato, plum)Delay in ripening (tomato, cantaloupe)Improved (healthier) oil content (canola, soybean)Reduced nicotine content (tobacco)Increased amino acid content (corn)
On the SF bartWhat do you think?
Genes for which we are testing: RuBisCo, Bt, 35S RuBisCo- 599 bp- found only in plants. An enzyme that converts carbon dioxide into sugars and carbohydrates for the plant. This is our internal control. Most abundant protein found in nature.
Bt- 421 bp cry gene (toxin gene) will indicate that the plant is genetically modified
35S promotor of the cauiliflower mosaic virus (CaMV 35s 221 bp -promoter element common in most transgenic plants. Its the start of a gene. Also indicates the plant is genetically modified)
Testing for GMOs in the field or pantryELISA uses a color-change system to signal the presence of a protein. Limits: protein must not be denatured, as is often the case in processed foods. PCR uses gene-specific primers to detect the presence of the transgene itself. Limits: expensive, not able to do in the field. * Enzyme-Linked ImmunoSorbent Assaywww.ilcrop.com
Golden RiceStaple food world-wide is deficient in Vit. AIngo Potrykus, et al. developed rice that produces beta carotene, precursor to Vit. AStill not available for human consumptionwww.goldenrice.org
Hawaiian papayasPapaya ring spot virus found in Hawaiian cropsCornell and Univ. Hawaii researchers developed papaya that produces viral coat protein
DNA cassettePROMOTERGENE OF INTERESTSCREENABLE/ SELECTABLE MARKER
Genetically modified foods: CornImage: msucares.edu Bt to protect from European corn borer RoundUp Ready (or other herbicide tolerance), to allow spraying of herbicides Corn and corn derivatives are found in almost all packaged foods (corn syrup, corn starch, etc.) In 2009, 85% of U.S. corn planted was genetically engineered Stacked varieties
Genetically modified foods: SoyImage: cropwatch.unl.edu In 2009, 91% of soy planted in the U.S. was engineered Herbicide tolerance is the only modification of soy Soy and derivatives are found in most packaged foods Important as animal feed
Genetically modified foods: CottonImage: ipm.ncsu.edu In 2009, 88% of U.S. cotton planted was engineered Both Bt and herbicide tolerant varieties Cotton isnt just clothing:cottonseed oil is present in many food items
3. There are 2 sequences of DNA that are most associated with GMOs. 35 S promotor of the cauiliflower mosaic virus (CaMV 35s)Terminator of the nopaline synthase (NOS) gene of Agrobacterium tumefaciens.We will look for either or both of these sequences in the food that we test.PCR will allow us to isolate those segments of DNA and copy them.An electrophoresis will give us a visual of the segments.
Genetically modified foods: Canola In 2005, 80% of Canadian canola was engineeredImage: canola-council.org Herbicide tolerant varieties
Canola is touted as one of the healthiest oils
DNA sequence based on a known genegeneofinterest(goi)+ ligase andopen plasmidPlasmid (circular DNA from bacteria)Electroporate into Agrobacterium tumefaciensplasmidHost DNAleaf disksScreen for transformants using selectable marker
Pot transformed plantsand propagateTransfer to shoot and root growth mediaIncubate leaf diskswith AgrobacteriumThe gene of interest is inserted into the chromosomes of the plantwith helper proteinsAgrobacterium injects thegene of interest into the plant cellEach cell of the plant containsthe new gene of interestgeneofinterestselectablemarkernucleus
PCR is a method to amplify DNATransfer genes by transformation- what do you need? A plasmidThe bacteria Agrobacterium has a Ti plasmid (tumor inducing plasmid) that allows you to insert new genes (foreign DNA) regardless of size). Normally Ti causes tumorsScientist have engineered a cassette (sequence of genes) and are able to insert new genes much more easily.Bt gene confers resistance to insects
B. GMO PCR productCheck plant pcr: is there a 455 bp band from GMO + (lane 5)?Check GMO PCR: is there a 203 bp band from GMO + (lane 6)
Types of genetic modification in plantsSelective breedingselecting traitsmarker assisted breedingradiation/ mutagen inducedHybridization (triticale)
Grafting (rootstock and scion)
Genetic engineeringImage: farrer.csu.edu.au