Genetic Engineering of Plant (2)

7/31/2019 Genetic Engineering of Plant (2)

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Genetic Engineering of Plants

By: Shubham Dwivedi

2010UBT 010


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GENETIC ENGINEERING OF CROP PLANTS

Plants have been genetically manipulated by plant breeders for decades

Today, however, pant breeders can directly modify the DNA of plants, and

they can quickly add genes from other species to plant genomes by DNA

recombinant techniques

An important feature of plant cell is their totipotency

This totipotency of plant cell is a major advantage for genetic engineering

because it permits the generation of entire plants from individual modified

somatic cells


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Genetic engineering: using molecular biology methods to modify the genetic

information of an organism.

To learn about the biology of an organism

To generate a new or improved commercial product

Plant biotechnology: manipulating or modifying plants to improve agriculture

or to generate a new or improved commercial product.

Genetically modified organisms (GMOs):

Organisms are modified by genetic engineering to express desirable traits.


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Three Major Reasons for Developing Transgenic Plants

The addition of genes often improves the agricultural, horticultural, orornamental value of a crop plant

Transgenic plants can act as living bioreactors for the inexpensive

production of economically important proteins or metabolites

Plant genetic transformation (transgenesis) provides a powerful means

for studying the action of genes during the development and otherbiological processes


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WHY TRANSGENIC?

Some of the genetically determined traits that can be introduced into plants

by a single gene, or possibly, a small cluster of genes include

Insecticidal activity

Protection against viral infection

Resistance to herbicides

Protection against pathogenic fungi and bacteria

Delay of senescence

Tolerance to environmental stresses

Altered flower pigmentation

Improved nutritional quality of seed proteins

Increased post harvest shelf life and self incompatibility

Improved nutritional quality of seed proteins


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To date, over 140 different plant species have been genetically transformedincluding many crops and forest species, in over 50 different countries worldwide.

Plant Biotechnology is having an enormous impact on plant breeding programs

because it significantly decreases the 10 to 15 years that it takes to develop a new

variety using traditional plant breeding techniques


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Methods to introduce DNA fragments to plants

Agrobacterium

Virus

Chemically induced

Physically assisted


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The bacterium can transfer its own DNA into plants and modulates plantgrowth and development (causes crown gall disease)

Efficiently transforms many dicotyledonous plants

Problematical with monocots

Agrobacterium


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Agrobacterium contains Ti plasmid and T-DNA

Agrobacterium has two types of DNA:

chromosomal DNA

Ti plasmid

Ti plasmid: Tumor inducing plasmid

T-DNA:transfer DNA, a portion of the Ti plasmid that is transferred into a host


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The main steps involved in Agrobacterium-mediated

gene transformation

1. Agrobacterium attaches to the plant cell surface and forms a pilli.

2. Bacterial proteins cleave, bind, and transfer the bacterial T-DNA to theplant cell.

3. The bacterial T-DNA is integrated into the plant chromosomes.


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The Ti plasmid is key for

Agrobacterium-mediated gene

transformation

Important Features On a Ti-Plasmid: Replication origin: required for DNA replication.

Virulence regions: genes required for T-DNA cleavage, binding,

translocation, and possibly integration. Onco genes: responsible for auxin and cytokinin production. They are

required for tumor growth of the infected plant.

Opine metabolic genes: required for opine synthesis and catabolism, the

nitrogen source for the survival of Agrobacterium.


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Ti plasmid


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NSAIDs

Owing to the increased susceptibility of the elderly to the side-effects of

NSAIDs the following recommendations are made:

for osteoarthritis, soft-tissue lesions, and back pain, first try measuressuch as weight reduction (if obese), warmth, exercise, and use of a walking

stick;

for osteoarthritis, soft-tissue lesions, back pain, and pain in rheumatoid

arthritis, paracetamol should be used first and can often provide adequate

pain relief; alternatively, a low-dose NSAID (e.g. ibuprofen up to 1.2 g daily) may be

given;

for pain relief when either drug is inadequate, paracetamol in a full dose

plus a low-dose NSAID may be given;

if necessary, the NSAID dose can be increased or an opioid analgesic givenwith paracetamol;

do not give two NSAIDs at the same time.


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Thank You

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Genetic Engineering of Plant (2)