A new finding could prove instrumental for future food security — Australian researchers have found a way to help plants survive for 50% longer during severe droughts.

Dr Su Yin Phua, Dr Kai Xun Chan, Diep Ganguly, and Estee Tee, in the lab. Image credits: Stuary Hay, ANU.

As the climate continues to get hotter and hotter, drought becomes a more likely possibility. Just look at California, for example. The US state underwent its most severe drought in the past 1,200 years, and might be locked in a drought cycle that will last centuries. California is also not an isolated case. Aridity is on the rise and it will threaten crops in many parts of the world. Ensuring that plants can survive these tiring parts will be crucial in this case, and this new finding might just make a difference for millions of people.

The research team, led by Dr Wannarat Pornsiriwong, Dr Gonzalo Estavillo, Dr Kai Chan and Dr Barry Pogson from the Australian National University (ANU) Research School of Biology, found that chloroplasts, more known for their role in photosynthesis, play a role in regulating plant hormone during heat stress.

“This basic scientific research has the potential to be able to improve farming productivity not just in Australia, but potentially in other countries that suffer from drought stress,” Dr Pogson said. “If we can even alleviate drought stress a little it would have a significant impact on our farmers and the economy.”

A chloroplast is a type of organelle strongly influenced by light intensity. They are the agents that conduct photosynthesis, where the pigment chlorophyll captures the energy from sunlight and converts it and stores it in energy-storing molecules. But as researchers found, chloroplasts can sense drought stress, and activate a chemical that closes the plant’s pores (stomata) to conserve water.

Colorized electron microscope image of a stoma on the leaf of a tomato plant. Image credits: Dartmouth University.

“Chloroplasts are actually capable of sensing drought stress and telling the leaves to shut-up and prevent water from being lost during drought stress,” he said. “So the chloroplasts are actually helping the plants to prevent losing too much water.”We know how the drought alarm actually calls for help and we know how help comes in the form of closing pores on the leaves.”

“Boosting the levels of this chloroplast signal also restores tolerance in drought-sensitive plants and extended their drought survival by about 50 per cent,” Dr Chan added.

Boosting the activity of the chloroplasts or stimulating this chemical signal in another way, then plants could store water for a longer period and survive for longer. This could be accomplished through genetic or agronomic ways, and the team is now working on developing the best approach.

Journal Reference: Wannarat Pornsiriwong et al — A chloroplast retrograde signal, 3′-phosphoadenosine 5′-phosphate, acts as a secondary messenger in abscisic acid signaling in stomatal closure and germination. Elife. doi: 10.7554/eLife.23361.