Translated by Mark Inglin
Instances of crop failures throughout the world are increasing. One
reason is more frequent periods of drought. To help alleviate the problem,
scientists are developing genetically modified, economically beneficial
plants that grow well even with little water.
Farmers face hard times - heat and periods of drought in many regions
are causing a shrinkage of the world's harvest yield. The fault is
attributable to climate change. The summer of 2003, which reduced plant
growth in Europe by one quarter, provided a sampling of what the future
holds. The insurance industry estimates average economic losses from drought
damage on German acreage at approximately 200 million Euro per year. In the
final analysis, the cost of such damage is born by consumers who pay more
for foodstuffs.



The World Health Organization is not the only body that recognizes an
opportunity to feed the world through green biotechnology. The EU also
attributes an important role to plant biotechnology in its "Plants for the
Future" program. In view of climate change, plants that are genetically
modified to resist environmental stresses such as heat, drought, or saline
soils will contribute to an increase in crop yields and quality. According
to a study by the International Water Management Institute, by the year 2025
one-third of the world's population will live in areas where water is
scarce.



To date, scientists have changed two primary properties of
economically beneficial plants in the lab by applying genetic engineering.
The first modification allows plants to produce substances that are
poisonous to damage-causing insects as a result of the introduction of a
bacterial gene that protects plants from attack. Together with resistance to
certain herbicides, which is achieved by introducing the appropriate foreign
genes, these two features are found in 99 percent of all transgenic plants.
Worldwide, such plants have been cultivated on a total of over 100 million
hectares. This constitutes a surface area approximately the size of France
and Spain combined.



Transgenic cultures, comprising mainly soya, corn, rape, and cotton
have conquered seven percent of worldwide available farm acreage in only one
decade. This year, that figure may rise to as much as ten percent, as
estimated by the International Service for the Acquisition of Agribiotech
Applications. The main areas of cultivation are found in the USA, Canada,
Argentina, Brazil, China, and India. This amounts to a billion dollar
business for enterprises that not only supply the seeds but also the
required insecticides and herbicides. As a result of the technology, farmers
can hope to realize higher harvest yields and easier maintenance of plant
cultures. However, this benefit does not come close to balancing plant
losses suffered from drought stress.



"Stress costs cultivated plants more energy than is necessary and, as
a result, reduces yield by up to 80 percent," says Michael Metzlaff, Head of
the Crop Productivity Research Group at Bayer Crop Science in Gent, Belgium.
Scientist there are working on a new generation of plants that have been
modified using gene technology. Their goal: plants should be more tolerant
of environmental stress. "Research results show that abiotic stress factors
such as drought, heat, cold or saline soils are closely related to the
energy balance in plants," explained Metzaff.



As a reaction to stress, plants activate defensive strategies in their
cells. Of pivotal significance in the process is the so-called PARP enzyme.
It results in the accelerated degradation of energy reserves and amplifies
plant respiration. Consequently, free radicals form in the cells,
permanently damaging the plants. The Bayer researchers have down-regulated
the genetic expression of the PARP enzyme to such an extent that defense to
stress is still maintained, but without impairing the growth of the plant.
"We throttle the overreaction of the cultured plant via PARP to the
necessary degree," says Metcalf.



To achieve this, the researchers are applying a relatively new method
by means of which protein activity can be incrementally diminished - not
unlike the action of a dimmer switch. By applying a procedure known as RNA
interference, snippets of molecules injected into cells ensure that the
transcription product of the genetic blueprint - that is, RNA - is captured.
The process has the effect that the genetic information is no longer
converted into proteins, and these then become more or less active.



Field tests in Canada with rapeseed plants that have been modified in
this manner and exposed to drought stress ran very successfully, according
to a Bayer researcher. "We have observed yield increases of up to 40%."
Farmers should be able to purchase new, stress-tolerant, high capacity
varieties of rape, cotton, rice, and corn by 2015.



That same goal is also being pursued by BASF's affiliate enterprise,
Plant Science, together with the US agro-concern, Monsanto. BASF researchers
are currently working on a new variety of corn in which a gene from a
drought tolerant moss allows the plants to better withstand drought. The
technology will be transferred to other cultivated plants, such as rape and
wheat. Stress tolerant seed varieties are expected to be on the market
between 2012 and 2015.



Industry leans on basic research to realize developments such as
these. Plant genome projects have thus provided numerous new starting points
relating to how genes can influence the energy balance in plants. Scientists
from the University of Bonn have identified a gene that protects the South
African resurrection plant, Craterostigma plantagineum, from drought. The
key in this plant is genetic programming: during a shortage of water the
plant appears to waste away, only to rise again following the first rain
shower after weeks or even months of drought.



The emergency plan for resurrecting the plant resides in its genetic
inheritance: a number of genes are only read during a water shortage, while
others are completely turned off at the same time. "By looking at which
hereditary factors are active mainly in drought, we try to understand what
molecular processes make the plants so resistant," explains Dorothea
Bartels, Professor at the Botanical Institute of the University of Bonn.
She thus discovered a gene that is far more frequently read during a water
shortage than otherwise. This "drought" gene makes certain that the plant
deals well with poisons that form under drought stress. It contains the
blueprint for the detoxification enzyme, aldehyde dehydrogenase (ALDH).



The Bonn researchers have introduced the ADDH gene into a wall cress,
Arabidopsis thaliana, a beloved laboratory plant, and then inserted a sort
of turbo-charger ahead of it to cause the gene to be transcribed
considerably more frequently. This has led to success: the genetically
modified plants clearly withstood periods of drought longer, by more than 40
percent as compared to wild-type plants. The gene had yet a further positive
effect, though. The plants did better when salt concentrations were
elevated.



The anticipated climatic demands have accelerated research in
developing countries as well. Scientists at the Autonomous University of
Morelos, in Cuernavaca, near Mexico City, have incorporated a critical gene
taken from moss fern into the wall cress, in order to accumulate the sugar,
trehalose. This sugar protects cells of the genetically enhanced plant,
just as it does the moss fern, from death by drought. The enhanced plants
withstood two weeks of full drought undamaged. The procedure, patented by
the researchers, will also be converted to applications in wheat and lucern.



Open field trials have also proven successful. These have been carried
out by scientists from the Research Institute for Agricultural Gene
Technology, in Cairo, Egypt, with transgenic wheat plants. Compared to
conventional varieties, such plants flourish even when watering is reduced
by 87 percent.



The fact that researchers are not the only ones rushing to green
biotechnology, but that larger enterprises are also becoming interested, is
understandable from the good business opportunities that can be expected.
BASF is assuming a market potential of 50 billion US dollars for the year
2025. In comparison, developmental costs on average are 50 to 60 million US
dollars, as estimated by the Swiss Biotechnology Work Group.



Nevertheless, billions in turnover cannot be expected immediately.
Developing a transgenic plant takes six to twelve years. "Resistances to
drought, heat, cold, and high salt concentrations rely on a complex
interplay of numerous genes and metabolic pathways. When plants are under
drought stress, they activate at least four independent metabolic pathways,
which in turn switch on a series of genes," states the Swiss Biotechnology
Work Group in its report that appeared in 2004, on second and the third
generation transgenic plants. The report was entitled, "Postponed Market
Maturity." It therefore remains questionable whether simple, initial
attempts using genetic engineering that rests on a single gene can lead to
success.



This article was originally printed in German by Silvia von der Weiden
in the newspaper, Die Welt.



Mark Inglin is a Science Writer for Checkbiotech in Basel,
Switzerland.



www.checkbiotech.org