One benefit of the method is that it is heavily regulated by the government, while each year
dozens of new plant varieties produced through traditional methods are marketed without any
scientific review or special labeling. Genetic splicing is a chemical process that involves using
restriction enzymes to cut the DNA of a gene to add base pairs. Each restriction enzyme
recognizes only a single nucleotide sequence and once it finds this sequence in a strand of DNA, it
splits the base pairs apart. This leaves single helix strands at the end of two double helixes, into
which any genetic sequences may be added. The chain is then repaired as a longer chain that
includes the added DNA with another enzyme, ligase.

Gene splicing will be applied to the most adaptable species of grass to be used for
phytoextraction, the most compatible remediation process. Grass is not currently a
hyperaccumulator, so the first gene to be modified will be the Metal Tolerance Protein 1, added to
the DNA sequence of the species. Once a hyperaccumulator, the rate of growth must be augmented
by inserting growth hormones and a gene that speeds the growth process. Although grass is a large
plant covering an expansive surface area, the root system will be extended to maximize toxic
uptake. A gene that does this will be transposed onto the genetic structure of the plant. It has
been found that the trait attributed to hyeraccumulation is under monogenic control (the tolerance
of each particular metal is controlled by a single gene). After absorbing the metal contaminants,
the grass will simply be mowed and composted in order to collect the metals, while the grass
regenerates itself. After five to ten years of crop rotation in this manner with the now ideal
hyperaccumulator, all metal will be removed from the brownfield site.

Though extensive research has been done on the study of phytoremediation,
scientists have yet to develop an ideal remediator. However, characteristics of such a
plant have been identified. An ideal plant would be a hyperaccumulator that can survive in
contaminated soils while stimulating microbial growth. This is essential because the
microbes actually break down the pollutants while the plants accelerate the degradation
by supplying oxygen and nutrients through their root systems. They are then able to
absorb the degraded contaminants.
The ideal plant for this process is a hyperaccumulator. To effectively accumulate a
metal, a plant must be able to efficiently absorb it, translocate it through the xylem,
unload it into the shoot tissues, and finally, sequester it into vacuoles, which, much like
the human liver, protect the plant from the metals' toxicity with a membrane-lined
structure. It is believed that hyperaccumulation is the result of the enhanced or ectopic
expression of a single component in one of these steps. Recently, however, scientists at
Purdue University may have located the gene accredited to causing the process. The gene
named by Dr. David E. Salt and his colleagues, Metal Tolerance Protein 1, was first
identified in the Thlaspi goesingense plant and has been located in 350 known
hyperaccumulators. However, the problem remains that these plants are small in scale
and, therefore, inefficient and undesirable in widespread use as phytoremediators.

The solution is to genetically modify larger plants otherwise containing desirable
characteristics to be hyperaccumulators. The best candidate for this is grass because of its
expansive surface area, adaptability to various climates, fast growth rate, regenerative abilities,
and the ease with which it is harvested. The most effective gene transfer technique is genetic
splicing because it is fast, precise and predictable, as opposed to other methods, such as
hybridization and induced mutation.
Before and After: One planting with tall fescue grass (right) was all it took
to clean the petroleum by-products out of a brownfield in Astoria, OR. (left)
Therefore, it is also beneficial to have an
extensive root system in order to increase
surface contact with the soil. One of the
major complaints of phytoremediation is its
low efficiency due to the slow growth rate
of the plants because it is necessary that
they reach maturity and are fully
functioning. Furthermore, most
hyperaccumulators are too small to cause a
significant effect. It is also necessary that
the plant grows high off the ground for
ease of harvesting and that it is adaptable
to various climates. An additional problem is
the potential volatilization of the pollutants
after they have been absorbed by the
plants. In the future, through improved
knowledge of the genome of all possible
phytoremediators, it will be possible to
genetically enhance and combine the
favorable characteristics of certain plants
while altering or removing their negative and
harmful tendencies. For example, a plant of
the Brassicacea family, an extremely
effective hyperaccumulator, is not ideal
because of its slow growth rate and
low-to-the-ground rosette architecture,
which makes harvesting difficult. When the
mechanics and specific gene structure of
the plant's abilities are identified, they may
be isolated and combined with a plant such
as a poplar sapling, which is both high to the
ground and able to mineralize the metallic
compounds in soil. This process will produce
an ideal remediator that is effective,
efficient and safe.

Future Uses
the extraction of gold, silver or other valuable metals that go undiscovered in the soil or exist only as trace

To rejuvenate soil made infertile from overuse (improving food quality and productivity- an inexpensive
alternative for third world countries

benefits to the United States economy (increased reliance on domestic markets, significantly less
funding necessary for environmental remediation

aesthetically pleasing alternative to current remediation techniques- increase of property value and
stimulation of tourism industry

the extraction of otherwise unobtainable fossil fuels from soil, assisting energy deficiency predicament
Transgenic Phytorejeuvenator Prototype
(before/after): This grass will be of the species
Sorghum vulgare sudanense (Sudan grass)
because of it's fast rate of growth, adaptability to
various climates, considerable height (this is
essential because root length is directly
proportional to the height of the grass, and for
harvesting purposes). After genetic enhancement
of the rejuvenator, previously inaccessible metal
contaminants will be translocated and stimulated
microbial growth will accelerate the degradation