Genetic Manipulation - Environmental Biotechnology: Theory and Application - page 228

A bacterial gene encoding pentaerythritol tetranitrate reductase, an enzyme
involved in the degradation of explosives, have been transferred into tobacco
plants. The transgenics have been shown to express the correct enzyme and
trials undertaken to determine the extent of their ability to degrade TNT (French
et al ., 1999).
Developments in the use of transgenic plants for bioremediation have
been reviewed (Francova et al ., 2001; Eapen, Singh and D'Souza, 2007; Van
Aken, 2009).
New products from plants
The rape plant, Arabidopsis thalia has become a popular choice for the pro-
duction of recombinant species. One such recombinant is a rape plant, the fatty
acid composition in the seed of which has been modified. It now produces tria-
cylglycerols containing elevated levels of trierucinic acid suitable for use in the
polymer industry (Brough et al ., 1996) and, in a separate project, polyhydrox-
ybutyrate suitable for the production of biodegradable plastics (Hanley, Slabas
and Elborough, 2000). Synthesis of the copolymer poly(3-hydroxybutyrate- co -
3-hydroxyvalerate) by Arabidopsis , is another example of the application of
Agrobacterium tumefaciens technology and the use of the 35S promoter from
Cauliflower Mosaic Virus (Slater et al ., 1999). This copolymer can be produced
by bacterial fermentation, but due to cost considerations, it is normally syn-
thesised chemically. This example is discussed further in Chapter 10 under the
umbrella of 'clean' technology. Progress in this field has been reviewed (Snell
and Peoples, 2002; Mooney, 2009).
Closing Remarks
It is something of an irony that GE is virtually synonymous with biotechnol-
ogy. The advances in this field have been enormous and, in many areas, are of
singularly great importance, yet its impact has been much less dramatic when
considering the purely environmental aspects. So much of what has been dis-
cussed in this chapter has not managed to make the wholesale transition into
mainstream commercial activity and whether it ever will still remains to be
seen, though the increase in patents in the field gives rise to some optimism
that it might. Genomics, for example represents one fast growing set of tech-
nologies which may assume greater importance in the field in the future. It
is something of a blanket term used to describe a broad swath of '-omic' disci-
plines, including the likes of genome architecture and sequencing, metabolomics,
proteomics and transcriptomics. Of the various potentially beneficial individ-
ual -omics, perhaps toxicogenomics - the examination of toxin-induced changes
in gene expression - could prove the most useful to environmental biotechnol-
ogy. If it can ultimately be developed to provide effective practical biomarkers
to help monitor ecological risk, it could open the way for a major decision
making tool and facilitate the choice and deployment of appropriate remedial