Name: transgenic plants for better crops
Uploaded: 2021-04-07T12:12:00.000Z
Duration: 2 min 50 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

NC K-12 Science Standard Course of Study

9-12

Biology

heredity-inheritance-and-variation-of-traits

Heredity- Inheritance and Variation of Traits

LS.Bio.8.2

Transgenic Plants

Les plantes transgéniques sont produites en introduisant un gène étranger dans le génome d’une plante. Ces plantes peuvent être développées pour diverses raisons, notamment la résistance aux virus ou aux ravageurs, un rendement plus élevé ou la production de protéines thérapeutiques.
Pour produire une plante transgénique, un gène d’intérêt et son promoteur sont introduits dans le protoplaste végétal, une cellule végétale sans paroi cellulaire, en incubant les deux dans un milieu contenant du polyéthylène glycol.
Le protoplaste recombinant est cultivé sur un milieu stérile en présence de régulateurs de croissance et de nutriments.
Les cellules du protoplaste se développent indéfiniment, produisant une masse de cellules indifférenciées appelée cal. Certaines cellules du dur, appelées cellules totipotentes, donnent naissance à de nouvelles pousses et racines, qui peuvent se développer en une toute nouvelle plante.
Des plantes transgéniques peuvent également être créées à l’aide de la bactérie Agrobacterium tumefaciens, une bactérie à Gram négatif présente dans le sol. Cette bactérie est un agent pathogène qui provoque normalement des maladies chez les plantes et contient un plasmide Ti qui peut s’intégrer dans le génome d’une cellule végétale.
Le plasmide Ti a deux régions d’intérêt : l’ADN-T ou la région d’ADN de transfert qui peut être insérée dans le génome de la cellule hôte et la région de virulence pour faciliter le transfert de l’ADN-T dans la cellule hôte.
Ce plasmide est modifié en insérant un gène souhaité dans la région de l’ADN-T et un gène de résistance aux antibiotiques pour permettre la croissance sélective d’organismes contenant des plasmides. Le plasmide recombinant est ensuite inséré dans la bactérie en appliquant une impulsion électrique pour augmenter la perméabilité cellulaire et permettre l’absorption du plasmide par la bactérie.
Le plasmide recombinant d’Agrobacterium tumefaciens est cultivé dans un milieu de culture contenant des antibiotiques.
Les parties de la plante telles que les nœuds cotylédonaires d’un plant de tomate sont coupées et incubées dans le milieu contenant des bactéries.
Les cellules végétales blessées au bord du nœud souche libèrent des composés qui attirent les bactéries. La bactérie infecte la plante et libère le plasmide recombinant, qui transfère ensuite le gène étranger dans le génome de la cellule végétale.
Seules les cellules transformées avec de l’ADN recombinant et des gènes résistants aux antibiotiques survivent dans le milieu contenant des antibiotiques.
Les cellules transformées forment maintenant un cal et se développent en une nouvelle plante transgénique porteuse d’un transgène.

<ol>
	<li>Ahmad P, Ashraf M, Younis M, Hu X, Kumar A, Akram NA, Al-Qurainy F. Rôle des plantes transgéniques dans l’agriculture et le biopharmaceutique. Biotechnol Adv. 2012 Mai-Juin ; 30(3):524-40. DOI : 10.1016/j.biotechadv.2011.09.006. Epub 17 septembre 2011. PMID : 21959304.</li>
	<li>Gelvin SB. Transformation des plantes par l’intermédiaire d’Agrobacterium : la biologie derrière l’outil du « gene-jockey ». Microbiol Mol Biol Rev. 2003 ; 67(1):16-37. doi :10.1128/MMBR.67.1.16-37.2003</li>
</ol>

plantes transgéniques.

La technologie de l’ADN recombinant appelée transgénèse est souvent utilisée pour ajouter un gène étranger ou supprimer un gène nuisible d’un organisme. Ces organismes génétiquement modifiés sont appelés organismes transgéniques.

La toute première plante transgénique était un plant de tabac développé en 1983 qui montrait une résistance au virus de la mosaïque du tabac. Depuis lors, de nombreuses plantes transgéniques ont été développées et commercialisées pour améliorer la valeur agricole, ornementale et horticole d’une plante cultivée. Les plantes transgéniques peuvent également être utilisées comme bioréacteur pour produire des métabolites ou des protéines économiquement importants.

Méthodes physiques de transfert de gènes aux plantes.

De nombreuses méthodes, telles que l’électroporation et le bombardement de microprojectiles, peuvent être utilisées pour transférer un gène étranger dans un protoplaste végétal. Pendant l'électroporation, un appareil délivre des impulsions haute tension à la suspension de protoplastes. Cela augmente la perméabilité du protoplaste permettant à l'ADN étranger de pénétrer dans la cellule et de s'intégrer dans le génome végétal.

En revanche, lors du bombardement de microprojectiles ou de la méthode biolistique, des particules sphériques constituées de tungstène ou d'or (microprojectiles) sont recouvertes du plasmide porteur du gène d'intérêt. Les particules enrobées sont ensuite accélérées jusqu'à 300 à 600 m/s avec un instrument appelé canon à particules. L’instrument utilise de l’hélium gazeux à haute pression pour fournir une force de propulsion qui aide les particules recouvertes de plasmide à pénétrer dans la paroi cellulaire végétale. Une fois à l’intérieur de la cellule, le gène d’intérêt s’intègre au génome végétal. Cette méthode peut être utilisée pour introduire de l’ADN dans des cultures de cals, des tissus méristématiques, des embryons immatures, des suspensions de cellules végétales, etc.

Applications des plantes transgéniques

La technologie de l’ADN recombinant est largement utilisée pour développer des plantes résistantes aux ravageurs et aux virus. La technique est également utile pour modifier la teneur en lipides, en amidon et en protéines des graines.

Par exemple, le riz doré est une plante de riz génétiquement modifiée ayant une valeur nutritionnelle améliorée. Cette variété de riz transgénique produit du β-carotène, un précurseur de la vitamine A, qui lui donne une couleur dorée. Il est produit par transformation de l'ADN médiée par Agrobacterium, où l'ADN recombinant portant trois gènes codant pour les enzymes phytoène synthase, phytoène désaturase et lycopène β-cyclase est inséré dans le génome des embryons de riz ciblés. Les embryons se développent ensuite en plantes qui produisent du β-carotène. Le riz doré a été développé pour lutter contre la carence en vitamine A dans les pays en développement.

Certaines autres plantes transgéniques, comme le coton Bt, ont été modifiées en insérant un gène isolé de la bactérie Bacillus thuringiensis, une bactérie à Gram positif présente dans le sol. Ces plantes transgéniques produisent une protéine cristalline ou « Cry » qui tue les insectes nuisibles, rendant la plante résistante aux insectes.

Plantes transgéniques.

La technologie de l’ADN recombinant appelée transgenèse est souvent utilisée pour ajouter un gène étranger ou supprimer un gène nuisible d’un organisme. De telle génétiquement...

Education

Enseignement

JoVE Core

Molecular Biology

Biologie moléculaire

Unit 2

Unité 2

Analyzing Gene Expression and Function

Analyse de l'expression et de la fonction géniques

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

transgenic plants for better crops

Transgenic plants are crops that have been changed with recombinant DNA technology, also called transgenesis. This method adds a foreign gene or removes a harmful one from an organism. The result is a genetically modified organism. The first transgenic plant was a tobacco plant made in 1983, and it was resistant to tobacco mosaic virus.

Since then, transgenic plants have been developed for many uses in agriculture, horticulture, and ornamental plants. Some are designed to resist pests or viruses. Others are used to improve the lipid, starch, or protein content of seeds. In some cases, transgenic plants can also act as bioreactors and make useful metabolites or proteins.

Foreign genes can be transferred into plant protoplasts by physical methods such as electroporation and microprojectile bombardment. In electroporation, high-voltage pulses make the protoplast membrane more permeable. This allows the foreign DNA to enter the cell and integrate into the plant genome. In microprojectile bombardment, also called the biolistic method, tungsten or gold particles are coated with plasmid DNA and shot into the cells with a particle gun.

The particle gun uses high-pressure helium gas to accelerate the coated microprojectiles to about 300 to 600 m/s. The particles can penetrate the plant cell wall and deliver the gene of interest. This method can be used with callus cultures, meristematic tissues, immature embryos, and plant cell suspensions. Once inside the cell, the introduced DNA can integrate into the plant genome.

A well-known example is golden rice, which has enhanced nutritional value. It produces β-carotene, a precursor of vitamin A, and this gives the rice its golden color. Golden rice was made by Agrobacterium-mediated DNA transformation using recombinant DNA with genes for phytoene synthase, phytoene desaturase, and lycopene β-cyclase. It was developed to help address vitamin A deficiency in developing nations.

Another example is Bt cotton. It contains a gene from Bacillus thuringiensis, a gram-positive soil bacterium. The plant makes Cry protein, which kills harmful insects and makes the crop insect resistant. These examples show how transgenic plants can improve crop value and help solve real agricultural problems.

Transgenic Plants for Better Crops

in vitro mutagenesis

In Vitro Mutagenesis for Gene Analysis

In vitro mutagenesis is a lab method used to change DNA and study gene function. It helps scientists test how specific DNA changes affect a gene’s activity and the traits it controls. A common approach is to make a known change in a DNA sequence and then examine the result. This can be done by deleting, inserting, or altering selected bases in a gene. The method is useful for linking a DNA change to a biological effect. Researchers use in vitro mutagenesis in molecular biology, genetics, and...

genetic screens

Using Genetic Screens to Find Disease Genes

Genetic screens are tools used to find genes and mutations linked to specific traits. They are also used to identify people or groups at risk for genetic diseases. That can support early intervention, targeted therapy, and reproductive choices. Forward genetic screens, also called classical screens, start with random DNA changes in an organism. Researchers may use radiation, mutagens, or added bases to create mutations that lead to visible phenotype changes. The mutant is then inbred so...

test cross

Test Cross in Genetic Inheritance

A test cross is a genetics tool used to determine the genotype of an organism with a dominant trait. It helps reveal whether the dominant individual is homozygous or heterozygous by crossing it with a recessive individual. The outcome of the cross shows the hidden genotype. If any offspring show the recessive trait, the dominant parent must carry one recessive allele. If all offspring show the dominant trait, the dominant parent is likely homozygous dominant. Test crosses are common in basic...

complementation tests

Using Crosses to Group Mutations

A complementation test uses a simple cross to find out whether two mutations are in the same gene or in different genes. It helps show how mutations are arranged on chromosomes. Edward Lewis first performed this test in the 1940s while studying fruit flies. To do the test, organisms heterozygous for different mutations are crossed pairwise in all combinations. If the mutations are in different genes, they can complement each other. In that case, each mutation provides the missing genetic...

single nucleotide polymorphisms-snps

SNPs as Genetic Markers and Variants

Single nucleotide polymorphisms, or SNPs, are small DNA changes at one specific genomic position. They are the most common type of sequence variation in the human genome. A point mutation counts as an SNP when it appears in more than 1% of the population.

bacterial transformation

Bacterial Transformation in the Lab

Bacterial transformation is a lab method used to move new DNA into bacteria. Scientists use it to change how bacteria behave or to help them carry a gene of interest. In high school biology, this process is often shown with plasmids, which are small circular DNA molecules. During transformation, bacteria take up DNA from their surroundings. The new DNA can then be used by the cell, depending on the experiment. This technique is an important part of genetic engineering and is widely used in...

transgenic organisms

Making Transgenic Organisms

Transgenic organisms are living things with DNA added from another organism. A transgene is the inserted gene. Scientists use this method to change an organism’s traits and to study how genes work. To make a transgenic organism, researchers first identify the gene they want to add. They then place that gene into the target organism’s DNA. Once the gene is integrated, the organism can pass it to new cells as it grows. This approach is useful in biology because it helps scientists analyze gene...

reproductive cloning

Cloning an Organism by Reproduction

Reproductive cloning creates a new organism that is genetically the same as the donor. It is different from cloning genes or cells because the goal is to make a whole living individual. This process usually relies on somatic cell nuclear transfer. In this method, the nucleus from a body cell is placed into an egg cell that has had its own nucleus removed. The egg can then develop into an embryo with DNA from the donor cell. Reproductive cloning is used to produce a copy of an organism, such...

crispr

CRISPR Gene Editing Basics

CRISPR is a gene editing tool that helps scientists make targeted changes to DNA. It uses a guide system to find a chosen sequence and a cutting protein to act at that spot. This method is based on a natural defense system found in bacteria. In high school biology, it is often studied as a way to see how genes can be edited with precision. CRISPR is widely used in molecular biology research. It helps scientists explore how genes function and how DNA changes can affect living things.

experimental rnai

RNAi for Gene Silencing and Discovery

RNA interference (RNAi) is a gene-silencing process used to reduce gene expression. It can block transcription or trigger RNA degradation. Scientists first discovered this mechanism in plants in 1998 through Andrew Fire and Craig Mello. RNAi has since been found in many eukaryotes, including protozoa, flies, nematodes, insects, parasites, and mammals. Researchers use it as a practical tool to study gene function. It can show what a gene does without permanently changing the organism’s DNA. <br...

reporter genes

Reporter Genes in Cells and Plasmids

Reporter genes are protein-coding genes used to track gene activity in cells. They are often tagged to a gene of interest so scientists can see whether that gene is present or active. When the tagged genes are expressed together, reporter genes can produce visible signals such as fluorescence or luminescence. These signals help show the presence or absence of a gene of interest in an organism. They can also reveal the pattern of gene expression or the location of a DNA segment or protein...

in-situ hybridization

ISH Probes for DNA and RNA Detection

In situ hybridization (ISH) uses labeled probes to detect and localize specific DNA or RNA molecules in cells, tissues, or tissue sections. The probe is a complementary strand of DNA or RNA that binds to a matching nucleotide sequence in the sample. Since its first use in 1969 for nucleic acid studies, ISH has become an important tool in research and in clinical diagnosis. Several probe types can be used in ISH. These include single-stranded DNA probes, double-stranded DNA probes, antisense...

chromatin immunoprecipitation- chip

ChIP Methods for DNA-Protein Binding

Chromatin immunoprecipitation, or ChIP, is an antibody-based method for finding where proteins bind to DNA. It is used to identify DNA sites bound by transcription factors or histone proteins. ChIP also helps show which histone changes are present, including acetylation, phosphorylation, and methylation. ChIP is commonly divided into two forms: X-ChIP and N-ChIP. X-ChIP first cross-links proteins to DNA inside the cell, then breaks the DNA into pieces by sonication. The protein-DNA complexes...

synthetic biology

Synthetic Biology in Crops and Cells

Synthetic biology combines engineering, molecular biology, cell biology, and systems biology to redesign living systems. Scientists use it to remodel organisms from nature or to build new synthetic organisms. These tools can support protein or enzyme production, bioremediation, the production of useful macromolecules, and the addition of helpful traits to crops. One well-known example is golden rice. This genetically modified rice plant makes grains rich in β-carotene, which is a precursor of...

ribosome profiling

Ribosome Profiling for Translation Snapshot

Ribosome profiling is a deep sequencing method that gives a snapshot of active translation in a cell. It sequences the mRNAs protected by ribosomes. This shows which messages are being read to make proteins at a specific moment. The method has several uses in biology. It can track translation in a living organ or tissue type. It also helps measure new protein synthesis levels. Researchers use it to find translated open reading frames, which are stretches of RNA that can make protein. It can...

transgenic plants

Transgenic plants are crops that have been changed with recombinant DNA technology, also called transgenesis. This method adds a foreign gene or removes a harmful one from an organism. The result is a genetically modified organism. The first transgenic plant was a tobacco plant made in 1983, and it was resistant to tobacco mosaic virus. Since then, transgenic plants have been developed for many uses in agriculture, horticulture, and ornamental plants. Some are designed to resist pests or...

gene therapy

Gene Therapy for Disease Treatment

Gene therapy is a treatment approach that changes gene activity to help address disease. It focuses on the genetic cause of a problem rather than only easing symptoms. In this way, it is used in disease intervention. One common strategy is to replace a faulty gene with a normal copy. Another strategy is to inactivate a gene that is causing harm. Gene therapy can also introduce a new gene to help cells work more normally.

epistasis analysis

Gene Interaction Maps in Epistasis

Gene interaction maps in epistasis show how different genes work together to shape a phenotype. In epistasis, the interaction of genes or alleles at different locations affects the final trait. This often happens when one gene masks or interferes with the expression of another gene. Epistasis is common when genes are part of the same biochemical pathway. In that case, the expression of one gene can depend on a gene product made earlier in the pathway. Genes that mask or inhibit other genes in...

genome-wide association studies-gwas

Using SNP Patterns to Link Disease Risk

Genome-wide association studies, or GWAS, look for common SNPs, or single nucleotide polymorphisms, that may be linked to disease. Researchers compare how often a SNP appears in people with a disease and in people without it. When a SNP is seen more often in the disease group, it is considered associated with that disease. GWAS uses chi-square analysis to test the chance that an allele is linked to the disease. This approach does not require scientists to first find the target gene behind the...

key terms and concepts

Learn how transgenic plants are made and used, from electroporation and biolistic gene transfer to golden rice and Bt cotton in crop improvement.

Transgenic Plants for Better Crops | JoVE K12

molecular biology

JoVE Core Biologie Moléculaire illustre les processus moléculaires au sein de la cellule grâce à des leçons vidéos claires et concises. Les applications de ces concepts sont ensuite démontrées grâce à des expériences concrètes en laboratoire.

Tennessee Academic Standards

High School

links-among-engineering-technology-science-and-society

Links Among Engineering, Technology, Science, and Society

BIO1.ETS2.1

BIO1.ETS2.3

Virginia  Standards of Learning

HIgh School

BIO.5

BIO.5.e

Arizona Science Standards

Life Science

HS.L3

HS.L3U3.26

Alabama Course of Study Science

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms: Structures and Processes

9-12.B.1.2.c

Georgia Standards of Excellence

SB2.c

What is Meiosis?

Meiosis is the process by which diploid cells divide to produce haploid daughter cells. In humans, each diploid cell contains 46 chromosomes, half from ...

Meiosis I

Meiosis II

Meiosis vs. Mitosis

Crossing Over

Crossing over is the exchange of genetic information between homologous chromosomes during prophase I of meiosis I. Genetic recombination gives rise to ...

Nondisjunction

Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate correctly and move to the opposite poles of the cells. This ...

Spermatogenesis

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Oogenesis

In human women, oogenesis produces one mature egg cell or ovum for every precursor cell that enters meiosis. This process differs in two unique ways from ...

Fertilization

During fertilization, an egg and sperm cell fuse to create a new diploid structure. In humans, the process occurs once the egg has been released from the ...

Cleavage and Blastulation

After a large-single-celled zygote is produced via fertilization, the process of cleavage occurs while zygotes travel through the uterine tube. Cleavage ...

Gastrulation

Gastrulation establishes the three primary tissues of an embryo: the ectoderm, mesoderm, and endoderm. This developmental process relies on a series of ...

Neurulation

Neurulation is the embryological process which forms the precursors of the central nervous system and occurs after gastrulation has established the three ...

Cell Migration

Cell migration, the process by which cells move from one location to another, is essential for the proper development and viability of organisms ...

Determination

During embryogenesis, cells become progressively committed to different fates through a two-step process: specification followed by determination. ...

Use models to explain how DNA is passed from parents to offspring through the processes of meiosis and fertilization in sexual reproduction.

LS.Bio.6.1

Mutations

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genome-size-and-the-evolution-of-new-genes

Genome Size and the Evolution of New Genes

types-of-genetic-transfer-between-organisms

Types of Genetic Transfer Between Organisms

Base-pairing and DNA Repair

The DNA Replication Fork

Lagging Strand Synthesis

The Replisome

Proofreading

Synthesis of new DNA molecules is carried out by the enzyme DNA polymerase, which adds nucleotides on the daughter strand complementary to the template ...

Replication in Prokaryotes

DNA replication has three main steps: initiation, elongation, and termination. Replication in prokaryotes begins when initiator proteins bind to the ...

Replication in Eukaryotes

In eukaryotic cells, DNA replication is highly conserved and tightly regulated. Multiple linear chromosomes must be duplicated with high fidelity before ...

Overview of DNA Repair

Base Excision Repair

Nucleotide Excision Repair

DNA Distortion and Damage
Cells are regularly exposed to mutagens&#8212;factors in the environment that can damage DNA and generate mutations. UV ...

Mismatch Repair

Organisms are capable of detecting and fixing nucleotide mismatches that occur during DNA replication. This sophisticated process requires identifying the ...

Fixing Double-strand Breaks

Homologous Recombination

Gene Conversion

Restarting Stalled Replication Forks

Construct an explanation to summarize how inheritable genetic variations may result from: new genetic combinations in meiosis, mutations during replication, or mutations caused by environmental factors.

LS.Bio.6.2

An Overview of Genetic Analysis

An organism&#8217;s physical traits, or phenotype, are a product of its genotype, which is the combination of alleles (gene variants) inherited from its ...

Genetic Crosses

To dissect genetic processes or create organisms with novel suites of traits, scientists can perform genetic crosses, or the purposeful mating of two ...

Punnett Squares

Monohybrid Crosses

Dihybrid Crosses

Trihybrid Crosses

Trihybrid Crosses
Some of Mendel&#8217;s crosses examined three pairs of contrasting characteristics. Such a cross is called a trihybrid cross. A ...

Law of Independent Assortment

Chi-square Analysis

The chi-square test is a statistical hypothesis test. It is used to check whether there is a significant difference between an expected value and an ...

Pedigree Analysis

Multiple Allele Traits

Incomplete Dominance

Gregor Mendel&#39;s work (1822 - 1884) was primarily focused on pea plants. Through his initial experiments, he determined that every gene in a diploid ...

Lethal Alleles

Agouti: A Lethal Allele
Lucien Cu&#233;not discovered lethal alleles in 1905 while studying the inheritance of coat color in mice. The agouti gene is ...

Polygenic Traits

background-and-environment-affect-phenotype

Background and Environment Affect Phenotype

Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as ...

Use mathematics and computational thinking to predict the variation and distribution of expressed traits based on: Mendelian inheritance, co-dominance, incomplete dominance, multiple alleles, and sex-linked inheritance.

LS.Bio.7.1

Overview

A pedigree is a diagram displaying a family&#x2019;s history of a trait. Analyzing pedigrees can reveal (1) whether a trait is dominant or ...

Probability Laws

Overview

The probability of inheriting a trait can be calculated using the sum and product rules. The sum rule is used to calculate the probability of ...

The Concept of Multiple Allelism

Multiple allelism describes genes that exist in three or more allelic forms. Although diploid organisms, like humans, ...

Analyze and interpret data to explain how polygenic traits result in a wide range of phenotypes.

LS.Bio.7.2

Pleiotropy

Pleiotropy is the phenomenon in which a single gene impacts multiple, seemingly unrelated phenotypic traits. For example, defects in the SOX10 gene cause ...

Nature and Nurture

Many human characteristics, like height, are shaped by both nature&mdash;in other words, by our genes&mdash;and by nurture, or our environment. For ...

Construct an explanation to summarize how traits result from interactions of genetic factors (multiple genes and/or alleles) and environmental factors.

LS.Bio.7.3

Understand genetic mechanisms for variation.

Transgenic Plants for Better Crops

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