Developing drought-proof crops

In a breakthrough that could lead to the development of drought-proof crops, research led by The Australian National University (ANU) has found how plants, such as rice and wheat, sense and respond to extreme drought stress.

Lead researcher Dr Kai Xun Chan, from the ANU Research School of Biology, said the team discovered an enzyme that senses adverse drought and sunlight conditions, and how this enzyme works from atomic to overall plant levels.

Dr Chan said the sensor in plant leaves is constantly assessing the state of its environment in terms of water and light levels and is able to sense when conditions become unfavourable — such as during extreme drought stress — by changing itself into a form with altered shape and activity.

“This sets off a ‘fire alarm’ in the plant, telling it to respond to drought by making beneficial chemical compounds, for instance. But in the field, this can occur too late and the plant would have suffered damage already. If we can get the alarm to go off at the first signs of water deficit, we can help the plant survive severe droughts,” said Dr Chan.

The development of drought-tolerant crops is crucial to ensuring global food security and can reduce the impact of drought on the national economy. A 2015 Climate Council report found that the Australian GDP fell 1% due to drought and lower agricultural production in 2002 and 2003.

Drought normally hits wheat at the flowering and seed stage, which is critical in determining the size of a crop’s harvest. By activating the sensor alarm faster during a dry season, the plant can activate countermeasures in its leaves to prevent unnecessary water loss and ensure that the plant survives until the next rainfall. 

“We’re really excited about the potential applications of this research, which range from genetic modifications and plant breeding to the development of a chemical spray that directly targets this sensor to set off the alarm in plants,” Dr Chan said.

Work by Dr Peter Mabbitt and Associate Professor Colin Jackson from the ANU Research School of Chemistry, using X-ray facilities at the Australian Synchrotron, enabled the team to create a 3D model of the sensor enzyme.

Dr Chan said they will use this model and a computer program to identify candidate chemical compounds that match well with the enzyme’s structure.