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In a world's first, scientists from CSIRO Plant Industry and Japan's Okayama
University have isolated an aluminium tolerance gene from wheat which will
accelerate the development of crops that can help battle Australia's $1
billion soil acidity problem, November 2004.

Acidity affects more than 40 per cent of the world's arable land, limiting
agriculture when naturally occurring aluminium dissolves and inhibits root
growth in sensitive plants.

The CSIRO team, led by Drs Manny Delhaize and Peter Ryan, and their Japanese
collaborators, isolated a wheat gene that enables roots to exude malate, a
normal constituent of plant cells, binding aluminium into a non-toxic form
and protecting roots from damage.

"Acid soil can be improved by using lime but it takes decades to correct
acidity at depth," Dr Ryan says. "By combining liming with acid tolerant
crops and pastures, nutrient leaching can be reduced and acidity effectively
managed."

"Aluminium tolerance is not present in many crop and pasture species,
including barley, so they cannot be improved by conventional plant breeding.
But as a single gene is responsible, gene technology is an ideal way to
introduce the tolerance trait.

To test the gene's effectiveness, scientists used genetic technology to
introduce the gene into barley - a plant normally very sensitive to
aluminium.

"The experimental barley showed a high level of aluminium tolerance in both
hydroponic culture and acid soils," Dr Delhaize says.

While CSIRO is not planning to release an acid soil tolerant GM barley, the
gene is already used as a molecular marker for tracking aluminium tolerance
in standard wheat breeding trials.

"Since the marker is based on the aluminium tolerance gene itself, it can be
used to select for the tolerance trait in breeding as a perfect marker,
improving the acid soil suitability of wheat by non-GM methods."

The research was undertaken in collaboration with scientists at Okayama
University's Institute for Bioresources, and is detailed in March Issue 5 of
The Plant Journal and in an October issue of the Proceedings of the National
Academy of Sciences (USA).

[www.csiro.au]
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