Australia
November 3, 2004
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.
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). |