Potential Risks and Benefits of Genetically Engineered Crops to Biodiversity Professor Abdelfattah Badr Faculty of Science, Tanta University 31527 Tanta, Egypt
[email protected] Fulbright Scholar CSU, CO, USA, Nov. 30, 2011
MAIN TOPICS OF THE TALK • DNA recombination and Gene • Breeding ≠ Gene transfer Examples and New Generation of GM Crop Plants (17 slides) • • • •
Biodiversity: Definition and types Importance and Economic Value of Plant Biodiversity Forms of Genetic Diversity; Wild and Cultivated Rational for Conserving Plant Diversity (12 slides)
• Potential Risks of GM Plants on Plant Biodiversity • Potential Benefits of Transgenic Plant (23 slides) • Safety Assessment for GM Plants and GM Food (3 slides)
DNA : The material of genes The Double Helix Molecule of life
Basic Natural Functions of DNA
Recombinant DNA & Gene Cloning
Breeding ≠ Gene transfer (1) • Breeding Beneficial gene added from the same species Gene delivered by mating within the species
• Gene transfer Beneficial gene added from another species Gene delivered by plant genetic engineering
Breeding ≠ Gene transfer (2) • Breeding Can only exchange genes found in the same species
• Gene transfer adds traits not available in the species Example Soybean does not have a gene to breakdown Roundup, the gene comes from bacteria
Production of Transgenic Plants Via Ti Plasmid and Agrobacterium Mediation
Gene delivery using gene gun machine (Biolistics)
Cartridge with DNA coated micro carrier
DNA coated micro carrier Filter Target tissue
The 1990s were the Decade of Gene Transfer to Plants
Most Commonly Transferred Traits Target (s)
Benefit (s)
Disease, Insect , Virus } resistance Cold , Drought , Salt } tolerance
Improve productivity of crops and reduce loss due to biological agents
Nitrogen fixation
Confer ability to fix atmospheric nitrogen
Nutritional value
Improve nutritional value of stored food, e.g. carotene, vitamins
Reduction of photorespiration
Increase efficiency of energy conversion
Storage properties
Extend shelf-life of fruits and vegetables, and resistance to spoilage and diseases
Consumer appeal
Make fruits and vegetable more appealing color, shape, size e etc
Permit growth of crops under environmental stress e.g. drought,
Percentage of most transferred traits
GM Plants on the Market (1) • Insect resistant cotton Bt toxin kills the cotton boll worm toxin gene from a bacteria GM cotton approved
• Insect resistant corn Bt toxin kills the corn borer toxin gene from a bacteria Rootworm GM approved
GM Plants on the Market (2) Herbicide resistant crops current: cotton soybean, corn, canola coming: sugar beet, lettuce, strawberry, alfalfa, potato, wheat (on hold) resistance gene from bacteria
Virus resistance papaya, squash, potato resistance gene from a virus
Compiled List of GM Crops
New Generation of GM Plants Golden Rice Increased Vitamin A and iron content Transgenes from bacteria and daffidol
Sunflower White mold resistance Resistance gene from wheat
Turf grass Herbicide resistance Slower growing Reduced pollution
Proposed Approach to Produce Golden Rice
Edible Vaccines – A Biopharming Dream Biotech Plants Serving Human Health Needs • A pathogen protein gene is cloned • Gene is inserted into the DNA of a plant (Apple, banana, tomato)
• • • •
Humans eat the plant The body produces antibodies against pathogen protein Human are “immunized” against the pathogen Examples: Diarrhea Hepatitis B Measles
WHAT IS BIODIVERSITY • The term biodiversity covers all levels of genetic and phenotypic natural variation at the molecular, individual, population, and ecosystem levels • Biodiversity is divided at three major levels – Ecological Levels – from populations to Ecosystem – Taxonomic – from clones to kingdoms – Genetic – from genes to genomes and phenotypes
Biodiversity Across the Living organisms
How much biodiversity is there on Earth?
The Convention on Biological Diversity Restricted Availability of Biodiversity as a Common Domain • The Convention on Biological Diversity (CBD) http://www.biodiv.org/) was signed in 1992 and came into force in 1993 • The objectives of this convention are:– Conservation and sustainable use of biological diversity
– Fair and equitable sharing of benefits of the use of genetic resources – Appropriate transfer of relevant technology for sharing the genetic resources
Article 15 of the CBD Genetic resources are subject to the sovereignty of individual states and collection of these resources requires prior informed consent This article—as well as the TRIPs agreement-made obsolete the nonbinding International Undertaking on Plant Genetic Resources, adopted in 1983 under the auspices of the Food and Agricultural Organization (FAO) TRIPs = Trade Related Aspects of Intellectual Property Rights
Treaty on Plant Genetic Resources for Food and Agriculture • The International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA) http://www.fao.org/ag/cgrfa/itpgr.htm), signed in 2001 by 140 countries but not yet entered into force harmonize the ITPGR with the CBD • In contrast with the CBD, which revolves around countryto-country relationships, this treaty is a multilateral agreement between members of the UN • Governments agree to provide other governments or ‘‘legal persons’’ within those countries with ‘‘facilitated access’’ to genetic resources belonging to a list of more than 100 crops and forages Examples from USDA
Importance of Plant Biodiversity • Plants constitute a green shield for the earth and provide the source of life for all living organisms on earth surface • Plants support ecosystem services that have indirect values (primary production, nutrient cycling, soil formation, crop pollination, water purification, climate regulation, disease control • Wild plants are indispensible genetic resources since they form the basis for agricultural development and act as a reservoir of genetic adaptability against environmental change
Economic Value of Plant Biodiversity • Biodiversity provides goods and services that have direct use values (food, wood, textiles, pharmaceuticals…), and is an inexhaustible source of innovations Example of pharmaceuticals: • More than 50,000 species are used for medicinal purposes • 41% of prescription drugs in the USA have their active ingredients derived from living organisms (25% from plants, 13% from microorganisms, 3% from animals) • Over 70% of promising anti-cancer drugs come from plants in the rainforests of Africa, South America and South Asia
Genetic resources of aromatic, spice and medicinal plants Genetic resources of decorative plants
Cultivated Forms of Plant Genetic Resources • Commercial varieties developed by professional breeders characterized by high productivity and genetic uniformity • Special genetic stocks conserved in plant breeders’ collections for use in developing commercial varieties • Land races or local varieties primitive cultivars evolved over centuries and thousands of years and have been influenced by both natural and artificial hybridization Land races and local varieties are therefore the reservoir of genes for sustainable agriculture
Forms of Cultivated Plant Biodiversity
Future Possibilities of Plant Biodiversity • New food sources • New medicines • New sustainable energy sources • New technologies • Maintenance of sustainable ecosystems Based on the above direct possibilities, biodiversity conservation and development are reflected on the socioeconomic stability
Rational for Conserving Plant Diversity • i The economic value of plants as resources for • • • • • •
humanity, both now and in the future ii The role of plants in maintaining a stable environment iii The scientific value of plants iv Maintaining future options v Cultural values and symbolic use vi The role of plants in inspiring people vii The right of species to exist and their inherent moral value
Global Threats to Biodiversity • Human population growth • Climate Change • Global Warming • Increased CO2 levels • Loss of the Ozone Layer
• • • •
Loss of forests Desertification Soil erosion Increased extinction rates (half of all plant species might be lost by 2100)
Threats to Natural Plants Biodiversity In some regions of the world, plants are exposed to serious threats due to heavy human impacts such as :• • • • •
Resource extraction, e.g. overgrazing, mining Agricultural developments in marginal lands Urbanization of agricultural land Extensive use of herbicides Introducing new invasive species
These activities may lead to:– Loss of genetic diversity and habitat destruction – Diminishing populations, local extinctions
Human Population Explosion
Historic Rate of Species Extinct in the Flora and Fauna of the USA in 16 Decades
Historic rate of species extinction in the flora and fauna of the world
Potential Risks of Gene Transfer • Transformation of microbial strains used in gene cloning into virulent strains • Instability of GM traits in host organisms • Changes of inserted genes and gene products • Toxicity to environment, air, water and soil • The spread of diseases across species barriers • Genetic pollution via air, water, birds, insects
Potential Risks of Gene Transfer to Crop Plants • Gene flow into non target organisms • Losing purity of natural cultivars • New toxins and allergens in food • Impact on long -term food supply through dominance of the seed and breeding market by a few big international companies
Potential Risks of GM Plants on Plant Biodiversity Displacement of crops by weedy transgenic plants can be aided by competitive ability and gene introgression
• • • • • • •
Weediness Attributes of GM Plants Vegetative propagation via propagules Resistance to environmental stress Possession of pest/disease resistance Ability to change with seasonal variations Possession of toxic, allelopathic or anti-feedant chemicals Adaptation to new symbiotic microorganisms Sexual compatibility with weedy and indigenous species
Loss of Natural Vegetation • Loss of natural vegetation by transgenic crops engineered for increased stress tolerance, increased environmental range and ability to grow in a wider range of habitats • Adapting transgenic crops to agriculturally marginal land may also cause loss of natural vegetation • Extinction of natural genes, populations and species through hybridization and introgression of trans-genes in the genotype of native plants
Infiltration of Transgenes to Natural Vegetation Through hybridization of a transgenic crop with a related weedy or natural species Infiltrated transgenes may lead to • Altered plant pest resistance potential • Creation of herbicide-resistant weeds
Dependency on Large International Companies • The combination of intellectual property rights and molecular biology tools has made the development of transgenic cultivars by the private sector possible • Concurrently, the seed industry has been consolidating, so that a few companies now dominate the seed market for several crops; e.g. maize, cotton, soy bean, • This market concentration raises the possibility that the elite domesticated gene pool will become even more depleted of genetic diversity
Potential Benefits of GM Plants Promoting Awareness of Biodiversity and Conservation
All wild plants are now considered potentially useful sources of valuable genes, so the perceived value of biodiversity is increased. This will help in promoting and pursuing the conservation and in developing new strategies and technologies for sustainable use of plant biodiversity
Increased Productivity of Crops help Conserve Biodiversity
Transgenic crops are more productive than conventionally bred crops. This will help in producing sufficient food to bridge the gap between the ever-increasing world human population and food production. In effect this will lessen the encroachment of natural, biodiversity rich habitats for agricultural development
Potential Benefits of GM Plants • Plants transformed to produce pharmaceuticals save wild plants currently harvested for use as medicinal plants • The production of transgenic crops more resistant to pests and pesticides and of new crops and crop symbionts for nitrogen fixation should reduce the need for agrochemicals (e.g. pesticides and fertilizers) that cause environmental damage
Potential Benefits of GM Plants • In principle: Gene technology provide new approaches and tools to protect, conserve and maintain biodiversity • Crops transformed to clean up pollution will help improve and preserve biodiversity, plants and microorganisms are engineered for mining • Rare and/or endangered species could be engineered for survival via introduction of genes for stress tolerance
Land Mines Indicators Plants Land Mines are serious danger to innocent civilians in many countries: Egypt, Vietnam, Lebanon, Afghanistan
Land Mines Indicators Plants • Patented trans-gene added to plants • When metal from mine is detected • Plant turns from green to red • Technology developed by Aresa Biodetection
Mine detected
Engineering plants for Phytoremediation Bioremediation • Use of living organisms or their products to cleanup contaminated sites. • also includes use of microbes designed to degrade the pollutant Use of engineered plants to biodegrade polluting substances = Phytoremediation
Bacteria help in phytorenediation Plants can take up pollutants and the pollutant metabolites formed by bacteria and convert them further or detoxify them
Bacteria
Novel Transgenic Approaches to Phytoremediation • Plants lack catabolic enzymes necessary to achieve full mineralization of organic molecules, potentially resulting in the accumulation of toxic metabolites • Transgenic plants exhibiting new or improved enzymatic machinery necessary to achieve a complete mineralization of organic molecules from bacterial and mammalian genome can be used to complement the metabolic capabilities of plants
Candidate Genes Metal Transporters • Transfer of Zn transporter-ZAT gene from Thalspi to Arabidopsis thaliana resulted in 2-fold higher Zn accumulation in roots • Introduction of calcium vacuolar transporter CAX-2 from Arabidopsis thaliana to tobacco resulted in enhanced accumulation of Ca and Cd
Metallothioneins • Transfer of human MT-2 gene in tobacco or oil seed rape resulted in plants with enhanced Cd tolerance • Pea MT gene in Arabidopsis thaliana enhanced Cu accumulation
Safety Assessment for GM Plants •Target organism •Transgene •GM trait •GM organism •Potential environment interaction
• Research • Research – Cloning • Confined field trial • Confined release • Variety registration and commercialization
Biosafety Recommendations for GM plants • Strict laboratory procedures to protect researchers from infection by genetically engineered microbes • Adequate training and protection for personnel engaged in work with transgenic organisms • Strains of microorganisms and plants used in recombinant DNA experiments should be genetically crippled to ensure that they cannot survive outside the laboratory • Certain dangerous experiments should be banned • Isolation of test sites of GM lines from sites of other crops • Monitoring direct and indirect effects on non-target organisms, particularly beneficial organisms
Safety Assessment of GM Food • (a) direct health effects (toxicity) • (b) tendencies to provoke allergic reaction (allergenicity) • (c) specific components that may have toxic properties • (d) the stability of the inserted gene • (e) nutritional effects associated with genetic modification • (f) any unintended effects which could result from the gene insertion
Before the Talk
After the Talk
Thank you
Abdelfattah Badr
