New molecule class creates hardy, drought tolerant plants
As climate change causes water scarcity and temperatures to rise, crops around the world are feeling the heat. How can we prevent severe crop losses in these relentlessly sweltering conditions? An international research team led by Tohoku University has identified a new class of small molecules that enhances plant drought tolerance without any major negative impact on plant growth.
The findings are posted in Nature Communications.
When plants perceive drought stress, they synthesize a key phytohormone called abscisic acid (ABA). ABA tells plants to close their stomata (similar to pores) to reduce water loss. While this defense mechanism helps conserve water, ABA also mediates unwanted responses, such as seed dormancy and growth inhibition.
"We want the plants to conserve water to improve survivability, but we don't want them to suddenly stop growing," explains Nobuyuki Uozumi (Tohoku University). "To achieve this ideal outcome, we devised a strategy of identifying compounds that inhibit molecules promoting stomatal opening."
The research team focused on the stomata in a model plant (Arabidopsis thaliana). Stomata are partially controlled by a channel called KAT1, which triggers stomatal opening by regulating K⁺ uptake. In other words, KAT1 is trying to keep the doors open—not a good strategy during a drought. The researchers aimed to find KAT1 inhibitors to keep the door tightly shut.
Compounds that shut the pores
To identify inhibitors of KAT1, the researchers performed an electrophysiological chemical screen and identified the small molecule NS5806. They then synthesized a derivative, UA49, by modifying its chemical structure. Application of either compound to leaf epidermal strips successfully induced stomatal closure and inhibited stomatal opening.
Moreover, foliar application of NS5806 or UA49 enhanced drought tolerance in plants. Importantly, unlike ABA, neither compound caused undesirable side effects, such as delayed seed germination or inhibited root growth, highlighting their potential for agricultural applications such as biostimulants.
A distinct calcium-linked pathway
In addition, the team elucidated the molecular mechanisms underlying the stomatal response induced by NS5806/UA49, which was distinct from ABA. They compared normal plants with plants modified to lack KAT1 channels and examined intracellular Ca²⁺ concentrations, a key mediator in signaling.
In normal plants, there was a sustained influx of Ca²⁺ in the guard cells that open and close stomata. In plants without KAT1 (the notorious door-opener), this response was absent. These findings suggest that the regulation of K⁺ channel activity is intrinsically involved in modulating intracellular Ca²⁺ signaling, pointing to a novel, previously unreported possibility that K⁺ channels act as signaling mediators.
Promise for drought-stressed crops
The research team found two compounds that confer drought tolerance with fewer side effects than ABA, making them promising candidates for improving drought tolerance in major crops. The underlying mechanism was also investigated, further highlighting how this strategy could potentially be applied. As climate change makes extreme drought more common worldwide, further research in this area is crucial to help ensure that the food supply doesn't just wither away.
Publication details
Kanane Sato et al, Synthetic ion channel inhibitors enhance plant drought tolerance, Nature Communications (2026). DOI: 10.1038/s41467-026-75894-w
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