Taking root in acid soils

In a world's first, CSIRO and Japanese collaborators have 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.

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.

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

To test the aluminium tolerance gene's effectiveness, scientists used genetic technology to introduce the gene into normally sensitive barley. The experimental barley showed a high level of aluminium tolerance in both hydroponic culture and acid soils.

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

Since the marker is based on the gene itself, it can be used as a 'perfect' marker to select for the tolerance trait in breeding, 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.

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