Have you ever driven by a cornfield during a prolonged period of drought and asked yourself ‘How do these plants survive?’ Well it turns out scientists have uncovered a protein in plants that holds the key to why some survive and others don’t. It’s called ABA INSENSITIVE GROWTH 1 (ABIG1) and it may determine the future of plant growth in an increasingly waterless world.
What is ABA?
ABA, or abscisic acid, is a hormone involved in many crucial plant developmental processes. During periods of drought, it triggers a number of water conserving strategies. ABA is what causes the pores on leaves to close up under stress (to prevent evaporation) and it slows growth when plants are struggling to draw water from the soil. ABA is also the agent that causes leaves to turn yellow and drop from the plant.
For some time, scientists have known that plants that are resistant to ABA are bad at coping with drought since they lack these vital survival mechanisms. Yet, in a surprising turn of events, researchers from the Carnegie Institution for Science in California have recently discovered that, when water is scarce, a subset of ABA-resistant plants actually grow better than their non resistant cousins.
“When breeders are looking for plants able to withstand drought, they discount those resistant to ABA, but our findings show that a subset of ABA-resistant plants may be a great source of drought tolerance,” Professor Kathryn Barton from Carnegie’s Department of Plant Biology in California told elife, who published the story.
Scientists arrived at this conclusion after conducting an experiment. They grew plants with and without the protein ABA and watered them for 34 days.
From day 35 on, they withheld water for 17 days. They discovered that the un-watered plants without ABIG1 retained double the number of green leaves, were able to remain upright and had stronger root systems. By contrast, those with the protein ABIG1 turned yellow, lost their leaves and fell over.
Barton and her colleagues hypothesized that by reducing the amount of ABIG1 in a plant, they could increase the threshold at which the plant triggers drastic water conserving measures. Raising the threshold would in turn help plants remain green and continue to grow during short-term periods of drought.
‘The ability of the plants we studied to remain green longer and to maintain an upright shoot even when we deprived them of water for over two weeks is an exciting discovery that could lead to more drought-tolerant crop varieties,” said Barton.
Aside from ensuring our gardens stay green, the new findings have broad implications for the future of our agriculture in an increasingly warmer world. And agriculture doesn’t just provide food, it is also our source of clothing, fuel and medicines. It remains to be seen if scientists will be able to develop plants with a resistance to a protein that, up to now, has been vital to their survival.
ABIG1 may be A-BIG-1 for the plant community.