Aug. 25 () –
Ethanol can help plants survive in times of droughtaccording to a new study conducted at the RIKEN Center for Sustainable Resource Science in Japan and published in the journal Plant and Cell Physiology.
Directed by Motoaki Seki Researchers have shown that adding ethanol to soil allows plants, including rice and wheat, to thrive after two weeks without water.
Because ethanol is safe, cheap and widely available, this finding offers a practical way to increase food production around the world when water is scarce, without the need to produce genetically modified plants, which are expensive, time-consuming and sometimes controversial.
The foreseeable future includes a steady population increase and a climate change-induced increase in water scarcity, two conditions that will inevitably lead to food shortages unless action is taken. One option is to find a way to prevent plants from dying when they don’t have access to water..
Genetically modifying plants so that their stomata – the pores in their leaves – remain closed has been somewhat effective because it prevents water from leaving the plants. However, making GM plants is expensive and time-consuming, and countries most in need may not have the same access to these GM crops.
Seki and his team have been working on another approach. Knowing that plants produce ethanol when deprived of water, they reasoned that giving it to the plants would protect them from future droughts. To test this hypothesis, they grew plants for about two weeks with plenty of water..
Next, they pretreated the soil with ethanol for three days, followed by water deprivation for two weeks. About 75% of the ethanol-treated wheat and rice plants survived after re-wateringwhile less than 5% of untreated plants survived.
Having shown that ethanol can protect these two important crops from drought, they set out to explain why by focusing on the model plant Arabidopsis.
First, they looked at the leaves and found that shortly after the ethanol-treated Arabidopsis plants were deprived of water, their stomata closed and leaf temperature increased. At 11 and 12 days of water deprivation, these plants had retained more water in their leaves than untreated plants..
The researchers then analyzed gene expression before and during water deprivation and radiolabeled the ethanol before pretreatment. This allowed them to see what processes were activated during the drought and what happened to the ethanol after it was absorbed by plant roots.
Even before water deprivation, the ethanol-treated plants began to express genes that are normally expressed during water deprivation. Furthermore, at about the same time that the water content decreased in the untreated leaves, the ethanol-treated plants produced sugars from the ethanol and photosynthesized.
Seki claims ethanol soil treatment mitigates drought on several fronts. First, drought-related genes are expressed even before the water is gone, giving plants a head start on readiness.
The stomata then close, allowing the leaves to retain more water. At the same time, some of the ethanol is used to make a number of sugars, which provide much-needed energy that is normally difficult to obtain with closed stomata.
“We found that treating common crops like wheat and rice with exogenous ethanol can increase crop production during drought. As in Arabidopsis, this is likely to occur through changes in the metabolomic and transcriptomic profiles that regulate response to drought, Seki said. This offers us a cheap and easy way to increase crop yields even when water is limited, without the need for genetic modification.“.
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