UC Riverside biochemists devise method for bypassing aluminum toxicity effects...( RIVERSIDE Calif. Aluminum toxicity ...)

RIVERSIDE, Calif. Aluminum toxicity, a global agricultural problem, halts root growth in plants, severely limiting agricultural productivity for more than half of the world's arable land.

For many years, scientists have puzzled over how toxic levels of aluminum damage the growing root. The popular understanding is that aluminum binds to several targets in the root system, blocking cell division, damaging DNA, and ultimately interrupting plant growth.

Now, working on the model plant Arabidopsis, a team of UC Riverside biochemists has determined that it is not aluminum toxicity that is directly responsible for inhibiting plant growth. The researchers identified a factor in plant cells, called AtATR, that functions as a built-in DNA surveillance system for alerting the plant of damage from excess aluminum and shutting down growth.

The researchers' experiments showed that AtATR can be manipulated to greatly enhance aluminum tolerance, resulting in plants whose roots can grow normally in soils that contain toxic levels of aluminum.

Study results appear in the Oct. 14 issue of Current Biology.

"Plants actively monitor aluminum-dependent damage through AtATR," said Paul Larsen, an associate professor of biochemistry and the lead author of the study. "But by breaking this assessment mechanism in a plant growing in soil with high aluminum content, we were able to stimulate plant growth again because the plant was no longer able to sense the damage aluminum caused. In other words, by bypassing this growth checkpoint, plants are not able to sense the effects of aluminum; they continue to grow even in an aluminum-toxic environment that is highly inhibitory to a normal Arabidopsis plant."

The research, which give
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