Transgenic plants are plants possessing a single or multiple genes, transferred from a different species. Though DNA from another species can be integrated into a plants' genome via natural processes, the term "transgenic plants" refers to plants created in a laboratory using recombinant DNA technology.
The aim of creating transgenic plants is to design plants with specific characteristics through artificial insertion of genes from other species (or taxonomically up to different kingdoms).
Varieties containing genes of two distinct plant species are frequently created by classical breeders who deliberately force hybridization between distinct plant species when carrying out interspecific or intergeneric wide crosses with the intention of developing disease resistant crop varieties.
Classical plant breeders use a number of in vitro techniques such as protoplast fusion, embryo rescue or mutagenesis to generate diversity and produce plants that would not ordinarily exist in nature (see also Plant breeding, Heterosis, New Rice for Africa).
Such traditional techniques (used from ca 1930) have never been controversial[opinion], or been given wide publicity except among professional biologists, and have allowed crop breeders to develop varieties of basic food crop. Hope is one such wheat variety bred by E. S. McFadden with a gene from a wild grass to have rust resistance. Hope saved American wheat growers from devastating stem rust outbreaks in the 1930s[citation needed].
Methods used in traditional breeding that generate plants with DNA from two species by non-recombinant methods are widely familiar to professional plant scientists, and serve important roles in securing a sustainable future for agriculture by protecting crops from pests and helping land and water to be used more efficiently.[citation needed] (see also Food security, International Fund for Agricultural Development, International development)
Natural gene flow between species
The aim of creating transgenic plants is to design plants with specific characteristics through artificial insertion of genes from other species (or taxonomically up to different kingdoms).
Varieties containing genes of two distinct plant species are frequently created by classical breeders who deliberately force hybridization between distinct plant species when carrying out interspecific or intergeneric wide crosses with the intention of developing disease resistant crop varieties.
Classical plant breeders use a number of in vitro techniques such as protoplast fusion, embryo rescue or mutagenesis to generate diversity and produce plants that would not ordinarily exist in nature (see also Plant breeding, Heterosis, New Rice for Africa).
Such traditional techniques (used from ca 1930) have never been controversial[opinion], or been given wide publicity except among professional biologists, and have allowed crop breeders to develop varieties of basic food crop. Hope is one such wheat variety bred by E. S. McFadden with a gene from a wild grass to have rust resistance. Hope saved American wheat growers from devastating stem rust outbreaks in the 1930s[citation needed].
Methods used in traditional breeding that generate plants with DNA from two species by non-recombinant methods are widely familiar to professional plant scientists, and serve important roles in securing a sustainable future for agriculture by protecting crops from pests and helping land and water to be used more efficiently.[citation needed] (see also Food security, International Fund for Agricultural Development, International development)
Natural gene flow between species
Natural flow of genes between bacterial species, often called horizontal gene transfer or lateral gene transfer, can occur because of gene transfer mediated by natural processes.
This natural gene movement between bacteria has been widely detected during genetic investigation of various natural mobile genetic elements, such as transposons, and retrotransposons that naturally translocate to new sites in a genome, and often move to new species over an evolutionary time scale.
There are many types of natural mobile DNAs, and they have been detected abundantly in food crops such as rice .
These various mobile genes play a major role in dynamic changes to chromosomes during evolution and have often been given whimsical names, such as Mariner, Hobo, Trans-Siberian Express (Transib), Osmar, Helitron, Sleeping Princess, MITE and MULE, to emphasize their mobile and transient behavior.
Genetically mobile DNA constitutes a major fraction of the DNA of many plants, and the natural dynamic changes to crop plant chromosomes caused by this natural transgenic DNA mimics many of the features of plant genetic engineering currently pursued in the laboratory, such as using transposons as a genetic tool, and molecular cloning. See also transposon, retrotransposon, integron, provirus, endogenous retrovirus, heterosis, Gene duplication and exon shuffling by helitron-like transposons generate intraspecies diversity in maize.
There is new scientific literature about natural transgenic events in plants, through movement of natural mobile DNAs called MULEs between rice and Setaria millet.
It is becoming clear that natural rearrangements of DNA and horizontal gene transfer play a pervasive role in natural evolution. Importantly many, if not most, flowering plants evolved by transgenesis[citation needed] - that is, the creation of natural interspecies hybrids in which chromosome sets from different plant species were added together. There is also the long and rich history of interspecies cross-breeding with traditional methods.
This natural gene movement between bacteria has been widely detected during genetic investigation of various natural mobile genetic elements, such as transposons, and retrotransposons that naturally translocate to new sites in a genome, and often move to new species over an evolutionary time scale.
There are many types of natural mobile DNAs, and they have been detected abundantly in food crops such as rice .
These various mobile genes play a major role in dynamic changes to chromosomes during evolution and have often been given whimsical names, such as Mariner, Hobo, Trans-Siberian Express (Transib), Osmar, Helitron, Sleeping Princess, MITE and MULE, to emphasize their mobile and transient behavior.
Genetically mobile DNA constitutes a major fraction of the DNA of many plants, and the natural dynamic changes to crop plant chromosomes caused by this natural transgenic DNA mimics many of the features of plant genetic engineering currently pursued in the laboratory, such as using transposons as a genetic tool, and molecular cloning. See also transposon, retrotransposon, integron, provirus, endogenous retrovirus, heterosis, Gene duplication and exon shuffling by helitron-like transposons generate intraspecies diversity in maize.
There is new scientific literature about natural transgenic events in plants, through movement of natural mobile DNAs called MULEs between rice and Setaria millet.
It is becoming clear that natural rearrangements of DNA and horizontal gene transfer play a pervasive role in natural evolution. Importantly many, if not most, flowering plants evolved by transgenesis[citation needed] - that is, the creation of natural interspecies hybrids in which chromosome sets from different plant species were added together. There is also the long and rich history of interspecies cross-breeding with traditional methods.
Deliberate creation of transgenic plants
Production of transgenic plants in wide-crosses by plant breeders has been a vital aspect of conventional plant breeding for about a century[citation needed]. Without it, security of our food supply against losses caused by crop pests such as rusts and mildews would be severely compromised[citation needed]. The first historically recorded interspecies transgenic cereal hybrid was actually between wheat and rye .
In the 20th century, the introduction of alien germplasm into common foods was repeatedly achieved by traditional crop breeders by artificially overcoming fertility barriers. Novel genetic rearrangements of plant chromosomes, such as insertion of large blocks of rye (Secale) genes into wheat chromosomes ('translocations'), has also been exploited widely for many decades [5].
By the late 1930s with the introduction of colchicine, perennial grasses were being hybridized with wheat with the aim of transferring disease resistance and perenniality into annual crops, and large-scale practical use of hybrids was well established, leading on to development of Triticosecale and other new transgenic cereal crops. In 1985 Plant Genetic Systems (Ghent, Belgium), founded by Marc Van Montagu and Jeff Schell, was the first company to develop genetically engineered (tobacco) plants with insect tolerance by expressing genes encoding for insecticidal proteins from Bacillus thuringiensis (Bt).
Production of transgenic plants in wide-crosses by plant breeders has been a vital aspect of conventional plant breeding for about a century[citation needed]. Without it, security of our food supply against losses caused by crop pests such as rusts and mildews would be severely compromised[citation needed]. The first historically recorded interspecies transgenic cereal hybrid was actually between wheat and rye .
In the 20th century, the introduction of alien germplasm into common foods was repeatedly achieved by traditional crop breeders by artificially overcoming fertility barriers. Novel genetic rearrangements of plant chromosomes, such as insertion of large blocks of rye (Secale) genes into wheat chromosomes ('translocations'), has also been exploited widely for many decades [5].
By the late 1930s with the introduction of colchicine, perennial grasses were being hybridized with wheat with the aim of transferring disease resistance and perenniality into annual crops, and large-scale practical use of hybrids was well established, leading on to development of Triticosecale and other new transgenic cereal crops. In 1985 Plant Genetic Systems (Ghent, Belgium), founded by Marc Van Montagu and Jeff Schell, was the first company to develop genetically engineered (tobacco) plants with insect tolerance by expressing genes encoding for insecticidal proteins from Bacillus thuringiensis (Bt).
Transgenic resistance traits in bread wheat varieties
The lists in this article may contain items that are not notable, encyclopedic, or helpful. Please help out by removing such elements and incorporating appropriate items into the main body of the article. (January 2010)
Important transgenic pathogen and parasite resistance traits in current bread wheat varieties (gene, eg "Lr9" followed by the source species) are:
Disease resistance
Leaf rust
Lr9 (from Aegilops umbellulata)
Lr18 Triticum timopheevi
Lr19 Thinopyrum
Lr23 T. turgidum
Lr24 Ag. elongatum
Lr25 Secale cereale
Lr29 Ag. elongatum
Lr32 T. tauschii
Stem rust
Sr2 T. turgidum ("Hope" ) McFadden, E. S. (1930) J. Am. Soc. Agron. 22, 1020-1031 .
Sr22 Triticum monococcum
Sr36 Triticum timopheevii
Stripe rust
Yr15 Triticum dicoccoides
Powdery mildew
Pm12 Aegilops speltoides
Pm21 Haynaldia villosa
Pm25 T. monococcum
Wheat streak mosaic virus
Wsm1 Ag. elongatum
Pest resistance
Hessian fly
H21 S. cereale H23,
H24 T. tauschii
H27 Aegilops ventricosa
Cereal cyst nematode
Cre3 (Ccn-D1) T. tauschii
Lepidoptera
Bt Bacillus thuringiensis
The lists in this article may contain items that are not notable, encyclopedic, or helpful. Please help out by removing such elements and incorporating appropriate items into the main body of the article. (January 2010)
Important transgenic pathogen and parasite resistance traits in current bread wheat varieties (gene, eg "Lr9" followed by the source species) are:
Disease resistance
Leaf rust
Lr9 (from Aegilops umbellulata)
Lr18 Triticum timopheevi
Lr19 Thinopyrum
Lr23 T. turgidum
Lr24 Ag. elongatum
Lr25 Secale cereale
Lr29 Ag. elongatum
Lr32 T. tauschii
Stem rust
Sr2 T. turgidum ("Hope" ) McFadden, E. S. (1930) J. Am. Soc. Agron. 22, 1020-1031 .
Sr22 Triticum monococcum
Sr36 Triticum timopheevii
Stripe rust
Yr15 Triticum dicoccoides
Powdery mildew
Pm12 Aegilops speltoides
Pm21 Haynaldia villosa
Pm25 T. monococcum
Wheat streak mosaic virus
Wsm1 Ag. elongatum
Pest resistance
Hessian fly
H21 S. cereale H23,
H24 T. tauschii
H27 Aegilops ventricosa
Cereal cyst nematode
Cre3 (Ccn-D1) T. tauschii
Lepidoptera
Bt Bacillus thuringiensis
Genetically engineered plants
Plums that have been genetically engineered to be resistant to the plum pox virus
The intentional creation of transgenic plants by laboratory based recombinant DNA methods is more recent (from the mid-70s on[citation needed]) and has been a controversial development in the field of biotechnology opposed vigorously by many NGOs, and several governments, particularly in Europe.
These transgenic recombinant plants are transforming agriculture in those regions that have allowed farmers to adopt them, and the area sown to these crops has continued to grow globally in every years since their first introduction in 1996.
As of 2006 there were around 250 million acres of genetically engineered crops being grown commercially in 22 countries[citation needed]. The U.S. has adopted the technology most widely whereas Europe has almost no genetically engineered crops. The EU had a formal ban on GM crops, until it was overturned in 2006; in a controversial move GM crops are now regulated by the EU.Transgenic recombinant plants are generated in a laboratory by adding one or more genes to a plant's genome,and the techniques frequently called transformation. Transformation is usually achieved using gold particle bombardment or through the process of Horizontal gene transfer using a soil bacterium, Agrobacterium tumefaciens, carrying an engineered plasmid vector, or carrier of selected extra genes.
Transgenic recombinant plants are identified as a class of genetically modified organism(GMO); usually only transgenic plants created by direct DNA manipulation are given much attention in public discussions[opinion].
Transgenic plants have been deliberately developed for a variety of reasons: longer shelf life, disease resistance, herbicide resistance, pest resistance, non-biological stress resistances, (e.g. drought or nitrogen starvation), and nutritional improvement (see Golden rice) and frost tolerance (see Fish tomato).
The first modern recombinant crop approved for sale in the U.S., in 1994, was the FlavrSavr tomato, which had a longer shelf life. The first conventional transgenic cereal created by scientific breeders was actually a hybrid between wheat and rye (triticale) in 1876 (Wilson, 1876). The first transgenic cereal may have been wheat, which itself is a natural transgenic plant derived from at least three parental species.
Genetically modified organisms came before commercially viable crops as the FlavrSavr tomato, only strictly grown indoors (in laboratories). However, after the introduction of the Flavr Savr tomato, certain GMO-crops (e.g. GMO-soy, GMO-corn, etc.) in the US were being grown outdoors on large scales.
Commercial factors, including high regulatory and research costs, have so far restricted modern transgenic crop varieties to major traded commodity crops[citation needed]. Recently, R&D has targeted enhancement of crops that are locally important in developing countries, such as insect-resistant cow-pea for Africa and insect-resistant Brinjal eggplant for India.
Transgenic plants have been used for bioremediation of contaminated soils. Mercury, selenium and organic pollutants such as polychlorinated biphenyls (PCBs) have been removed from soils by transgenic plants containing genes for bacterial enzymes.
Plums that have been genetically engineered to be resistant to the plum pox virus
The intentional creation of transgenic plants by laboratory based recombinant DNA methods is more recent (from the mid-70s on[citation needed]) and has been a controversial development in the field of biotechnology opposed vigorously by many NGOs, and several governments, particularly in Europe.
These transgenic recombinant plants are transforming agriculture in those regions that have allowed farmers to adopt them, and the area sown to these crops has continued to grow globally in every years since their first introduction in 1996.
As of 2006 there were around 250 million acres of genetically engineered crops being grown commercially in 22 countries[citation needed]. The U.S. has adopted the technology most widely whereas Europe has almost no genetically engineered crops. The EU had a formal ban on GM crops, until it was overturned in 2006; in a controversial move GM crops are now regulated by the EU.Transgenic recombinant plants are generated in a laboratory by adding one or more genes to a plant's genome,and the techniques frequently called transformation. Transformation is usually achieved using gold particle bombardment or through the process of Horizontal gene transfer using a soil bacterium, Agrobacterium tumefaciens, carrying an engineered plasmid vector, or carrier of selected extra genes.
Transgenic recombinant plants are identified as a class of genetically modified organism(GMO); usually only transgenic plants created by direct DNA manipulation are given much attention in public discussions[opinion].
Transgenic plants have been deliberately developed for a variety of reasons: longer shelf life, disease resistance, herbicide resistance, pest resistance, non-biological stress resistances, (e.g. drought or nitrogen starvation), and nutritional improvement (see Golden rice) and frost tolerance (see Fish tomato).
The first modern recombinant crop approved for sale in the U.S., in 1994, was the FlavrSavr tomato, which had a longer shelf life. The first conventional transgenic cereal created by scientific breeders was actually a hybrid between wheat and rye (triticale) in 1876 (Wilson, 1876). The first transgenic cereal may have been wheat, which itself is a natural transgenic plant derived from at least three parental species.
Genetically modified organisms came before commercially viable crops as the FlavrSavr tomato, only strictly grown indoors (in laboratories). However, after the introduction of the Flavr Savr tomato, certain GMO-crops (e.g. GMO-soy, GMO-corn, etc.) in the US were being grown outdoors on large scales.
Commercial factors, including high regulatory and research costs, have so far restricted modern transgenic crop varieties to major traded commodity crops[citation needed]. Recently, R&D has targeted enhancement of crops that are locally important in developing countries, such as insect-resistant cow-pea for Africa and insect-resistant Brinjal eggplant for India.
Transgenic plants have been used for bioremediation of contaminated soils. Mercury, selenium and organic pollutants such as polychlorinated biphenyls (PCBs) have been removed from soils by transgenic plants containing genes for bacterial enzymes.
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