Haifa, Israel
July 3, 2006
Source:
Israel21c
via
Checkbiotech
By David Brinn
Imagine what it would mean for the
world hunger problem if farmers could grow wheat and other crops
on land considered unsuitable for agriculture. That day may be
coming soon, after Israeli researchers from the
Institute of
Evolution of the University
of Haifa, have succeeded in isolating a gene that withstands
salinity.
"The research will contribute to a
significant increase in the amount of arable land available for
agriculture," said the institute's director Professor Eviatar
Nevo, who initiated and spearheaded the pioneering research.
Of the earth's 57 million square miles of land, approximately 12
million square miles are arable - meaning land that can be used
for growing crops. However, arable land is being lost at the
rate of over ten million hectares per year. Nevo's research will
make it possible to grow plants, including crops, in saline
earth, a development that will contribute in the future to a
true revolution in saline agriculture throughout the world.
Saline agriculture is the production of crops on land that is
affected by salt. Too much salt in soil or in irrigation water
will inhibit the growth of most crops, or may even kill them.
Saline soils are found in arid lands, in coastal deserts, and
where arable land has been ruined by poor farming practices.
Modern methods of irrigation and fertilization of crops has
caused much of the arable lands around the world to become
saline. This is especially true in drylands because of the high
rate of evaporation, which leaves the salt behind. More and more
farmers are forced to plant crops on marginal lands and to use
soil that was once arable but now has a high saline content.
To prove their research, Nevo's team went to the mother of
saline content - the Dead Sea - one of the most hypersaline
bodies of water in the world with a saline concentration ten
times that of the oceans. "Back in 1998, we discovered 77
different types of filamentous fungi in the Dead Sea, some were
rare and sporadic, and others were much more common and even
reached the bottom of the sea 300 meters down," said Nevo. "We
became interested in the fungi's genetic resources - what made
them thrive in the salty Dead Sea."
In the current study, Eurotium herbariorum, a common fungal
species, was isolated from the lake. One of Nevo's doctoral
students, Yan Jin, from China, then isolated and sequenced the
HOG gene that is responsible, in concert with other genes, for
the fungus' ability to defend itself from the salinity of the
Dead Sea.
The gene was introduced into 'saccharomyces cerevisiae' - better
known as baker's yeast - and the team observed that resultant
transgenic yeast was able to tolerate more salt than normal,
especially in resisting large temperature changes. The
researchers found that in comparison to yeast that was not
genetically engineered, the yeast that had been genetically
transformed by the insertion of the HOG gene was more durable in
saline or highly oxidative environments and also able to better
withstand extreme heat and cold.
"The gene helps the fungus to balance the internal salt content
of the cell through the production of the alcohol glycerol and
thus prevents the fungus from drying out and helps it defend
itself against salinity," said Nevo. "I expected the gene
transformation to increase the salt tolerance of the yeast. But
the tolerance to high and low temperatures proved to be a
surprise," he added.
The results of the study were published in the Proceedings of
the National Academy of Sciences [PNAS] of the United States. It
was another feather in the cap of the institute, which Nevo
founded in the mid-1970s. Consisting of 25 research
laboratories, the University of Haifa facility covers all
aspects of evolutionary biology, from ecological modeling and
ecological-genetics, to molecular evolution and cytogenetics,
associated with the twin evolutionary processes of speciation
and adaptation, and everything about evolution from bacteria to
humans.
Today the Institute of Evolution also hosts an international
graduate center of evolution, which currently houses 70 PhD
students from 10 countries, including Yan Jin from China. "We
also have another unit with 80 masters students and 1,300
undergraduates. We have collaborations with 500 labs in over 50
countries. Essentially we investigate all the problems connected
to evolutionary biology, both theoretical and applicative," said
Nevo, with no small amount of pride.
Having devoted 30 years of his life to building the institute
into a world-class center of learning, Nevo has no intentions of
slowing down. Since the study was published, Nevo said that the
team has gone a step further by also transferred the gene into
the model plants Arabi-dopsis, and have succeeded in making it
salt-resistant.
"The genetic salt resistant resources of the Dead Sea could be
very important for revolutionizing saline agriculture around the
world. If we can transform this gene and other genes we've
cloned, we'll be able to improve crop production by making them
salt tolerant and enable the growth of crops like wheat in a
tepid desert area. Our goal is to develop a battery of salt
resistant genes to be used for crop improvement."
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