Example of a drought-stricken crop field (maize)

Latest research: New plant compound could help crops survive drought

Scientists reveal how a synthetic molecule mimics a plant stress hormone and boosts drought resistance with several high-tech techniques, and help from a British-made photosynthesis analyser.

by Dr Ngoni Kangara, International Product Manager, ADC BioScientific Ltd

Plants suffer when they encounter long dry periods, which have become more common due to climate change. In a contribution toward drought-resilient crops, a collaboration by scientists from Spain and Estonia has reported in the highly reputable plant science journal Molecular Plant, the development of iCB, a novel synthetic molecule. iCB regulates the diffusion of gases such as carbon dioxide and water vapour through the stomata of plants (stomatal conductance) which helps plants retain water, survive heat, and continue growing even under extreme conditions. Plants treated with iCB continue photosynthesis for longer, even when exposed to extended periods of dryness. This work was published and offers a potential breakthrough for agriculture in a warming world.

Example of a drought-stricken crop field (maize)
Example of a drought-stricken crop field (maize)

Engineering a “Smart” Stress Signal for Plants

Plants produce the hormone abscisic acid (ABA) to survive drought. When water is scarce, ABA helps plants close the tiny pores on the leaves (stomata) to reduce water loss and initiate other protective responses inside the plant. The problem is that ABA degrades quickly and the speed of response to its application is slow. Farmers can spray synthetic versions of ABA on crops, but these treatments are not effective.

To solve this, the researchers developed a molecule called iCB, which is a synthetic ABA receptor agonist. iCB mimics the natural hormone but lasts longer and works across a broader range of plant species such as tomato, wheat and tobacco. Using techniques like plant gas exchange analysis, X-ray crystallography, High-Performance Liquid Chromatography and RNA Sequencing, confocal laser microscopy they showed how iCB fits into plant hormone receptors more precisely than older compounds like opabactin (OPA). It binds tightly, stays active longer, and initiates a strong drought response in the plant’s internal systems.

Fighting Drought in a Changing Climate

Natural ABA breaks down in sunlight or heat, whereas iCB remains effective longer and works across various crop types, including Arabidopsis, tomato, grapevine, and wheat. The application of iCB before water stress commences enables the plant to prepare for it, thereby enhancing plant survival and protecting crop yields.

Applied as a spray, iCB could become a powerful agricultural tool:

  • Reduce irrigation needs in drought-prone areas
  • Protect photosynthesis and yield during heatwaves
  • Improve water-use efficiency in crops
  • Activate stress resistance before extreme weather events

The researchers also showed that iCB boosts gene expression related to stress tolerance, like the production of osmolytes, natural compounds that help cells retain water and stay healthy.

In laboratory and greenhouse trials, plants treated with iCB survived longer, lost less water, and recovered better after drought. Therefore, iCB shows potential as a drought-resistance enhancer.

Measuring Photosynthesis under Stress

To measure how well iCB works, the team needed a precise, real-time way to monitor plant health, specifically looking at photosynthesis and transpiration.

Using the LCi-T Portable Photosynthesis System, made by ADC BioScientific Ltd (UK), the scientists:

  • Measured stomatal conductance, which is an indicator of the rate at which carbon dioxide is taken up and water vapour is lost through leaf stomata
  • Tracked the amount of carbon dioxide uptake and water vapour loss
  • Assess the impact of iCB treatment on photosynthetic efficiency
Illustration showing how leaves could respond to iCB application resulting in reduced water loss and maintenance of CO2 uptake
Illustration showing how leaves could respond to iCB application resulting in reduced water loss and maintenance of CO2 uptake

iCB-treated plants photosynthesised for longer periods under drought conditions and had higher water-use efficiency than untreated ones.

Final Thoughts

This research represents a cutting-edge blend of protein chemistry, plant physiology, and agricultural technology. By designing a stable, potent drought-response activator and verifying its effects with high-precision tools like the LCi-T, scientists are moving closer to creating crops that resist climate stress.

LCi-T photosynthesis and porometer device by ADC
LCi-T photosynthesis and porometer device by ADC

In the face of global water shortages and growing food demand, tools like iCB could become significant for sustainable farming.

Based on: Bono, M., Mayordomo, C., Coego, A., Illescas-Miranda, J., Rivera-Moreno, M., Infantes, L., López-Carracedo, P., Sanchez-Olvera, M., Martin-Vasquez, C., Pizzio, G. A., Merino, J., Forment, J., Merilo, E., Estevez, J. C., Albert, A., & Rodriguez, P. L. (2025). “Structural insight into ABA receptor agonists reveals critical features to optimise and design a broad-spectrum activator of ABA signalling.” Molecular Plant. https://doi.org/10.1016/j.molp.2025.07.014

Instrument featured: ADC BioScientific Ltd LCi-T Photosynthesis System

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