Plant found with built-in drought alarm

A signal found in plants could act as a drought alarm, allowing them to adapt to such extreme conditions.

Scientists stumbled on the signal while trying to understand how different parts of the cell chat with one another in the Arabidopsis thaliana, a kin of canola, under drought conditions.

A series of connected pathways, like the production lines of a factory, are inside every plant and animal cell. They are regulated by chemical signals and inputs, which can come from many sources.

Scientists have proposed for a while that chemical signals must be sent by a particular “plant department”, or organelle, to the nucleus, the cell’s control centre, for plants to become aware of and adapt to harsh conditions, according to an Australian National University (ANU) statement.

“The chloroplast is the plant organelle that converts light into food. The nucleus directs assembly and function of the chloroplast and this requires cross-talk between the two,” said ANU’s Gonzalo Estavillo, who led the study with Barry Pogson, a professor.

Now, research on a mutant variety of Arabidopsis has led to the discovery of a signal to the nucleus which is important in its response to drought.

The Arabidopsis mutant plant lacked a protein called SAL1, which breaks down a small molecule further down the production line called PAP.

As the protein was absent, the production line was broken, so PAP, which is usually found in the chloroplast, ended up building up in the nucleus.

Surprisingly, this became a kind of a drought alarm, telling the plant to save water. Consequently these mutant plants survived 50 percent longer in drought conditions.

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