www.checkbiotech.org ; www.raupp.info ; www.czu.cz

An extraordinary fungus that manages to thrive in the super-salty Dead Sea
could one day open up new genetic approaches to creating crops that can
tolerate saline soils, December 2005 by Kurt Kleiner.

The fungus Eurotium herbariorum is able to tolerate the Dead Sea's
incredible salt content of 340 grams per litre ? about 10 times saltier than
ocean water. Most of the Earth's organisms are far less tolerant of salt,
and will dehydrate and die if exposed to too much of it.

But researchers are interested in developing salt-tolerant food crops
because soil salinity is increasing in some parts of the world. Land that
needs to be constantly irrigated gradually becomes more saline, and crop
yields go down.

One way that cells respond to stress from salt is by manufacturing glycerol,
which helps keep water from migrating out of a cell. So researchers from the
University of Haifa in Israel isolated a gene called EhHOG associated with
glycerol production in the fungus and inserted it into brewer's yeast,
Saccharomyces cerevisiae.

They found the transgenic yeast was able to tolerate more salt than normal,
and that it had more tolerance for high and low temperatures and for
hydrogen peroxide. The researchers say if the gene could be inserted into a
plant, it might eventually be used to increase stress tolerance in crops.
They add that other genes from Dead Sea organisms might also be promising.

But Tim Flowers, a plant physiologist at the University of Sussex, UK, says
that fungi are so different from crop plants that there is no reason to
think the gene will be useful. He says salt tolerance is probably a trait
involving multiple genes, and it that it is unlikely that transplanting one
or two genes will result in crops with increased salt tolerance.

[www.newscientist.com]

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