A native Australian grass that plays dead during droughts and culls its own cells to survive could provide genetic keys to help food crops survive worldwide.

Like other so-called 'resurrection plants', Tripogon loliiformis has the ability to withstand desiccation (being dried out) for prolonged periods and can be revived by water but scientists have never known how these plants actually do it, or if the existing plant cells really do come alive again from a dormant state, or if its new growth is separate from the old cells. Professor Sagadevan Mundree of Queensland University have now proved sugar manipulation and the controlled sacrifice of cells are keys to the native grass's survival.

Previous experiments elsewhere had found that even after losing over 95 percent of its relative water content, the dead-looking outback Queensland grass was still alive and preexisting tissues again flourished when provided with water.

They found the grass (when hit by drought stress) accumulate trehalose (a non-reducing sugar found in plants) which it then used to trigger autophagy -- a process which allows the orderly degradation and recycling of plant cells.

Mundree said autophagy was primarily a survival mechanism that allowed removal of damaged proteins and recycling of nutrients, however, prolonged stress could result in excessive autophagy and death.

"Our analysis directly linked the accumulation of trehalose with the onset of autophagy in dehydrated and dried out T. loliiformis shoots. Presumably, once induced, autophagy promotes desiccation tolerance in the grass, by recycling nutrients and removing cellular toxins to suppress programmed cell death," Mundree said.

Published in PLOS Genetics.