Aluminum-Tolerance Gene Cloned in Sorghum

Plants have little liking to aluminum, especially if it is aluminum in acidic soils. Because of acidity, aluminum from clay minerals dissolves in the soil, and gets converted to its toxic charged (ionic) form. Aluminum toxicity in acidic soils is a big problem in crop production in as much as half the world's arable land, mostly in developing countries in Africa, Asia and South America, are acidic.

To provide plants with protection from aluminum, researchers at Cornell University have isolated a novel aluminum-tolerant gene found in some cultivars of sorghum. The gene expresses a protein in the root tip that release citric acid into the soil in response to aluminum exposure. Citric acid binds aluminum ions very effectively, preventing the toxic metal from entering the roots. The gene, they discovered, is only turned on when aluminum ions are present in the surrounding soil.

The researchers have now used the sorghum gene to engineer transgenic aluminum-tolerant Arabidopsis thaliana and wheat plants. New genetically-engineered aluminum-tolerant sorghum lines are expected next year.

Read the complete article at http://www.news.cornell.edu/stories/Aug07/SoilsKochian.kr.html.