A CSIC team has presented a molecule capable of helping plants to better manage the lack of water, with a performance that surpasses its own natural hormones. This innovation, called inverted cyanobactin (iCB), reproduces the pathway that plants use to respond to water stress.
Applied as foliar spray on tomato leaves, the molecule allows to withstand periods of intense drought and, after the episode, to recover photosynthesis without penalizing productivityThe results, published in Molecular Plant, have been protected by patent in collaboration with the Galician company GalChimia, the CSIC and the UPV.
How it works and why it matters
Most of the water is lost through the leaves via the stomata, pores that open and close depending on environmental conditions. In situations of water deficit, the phytohormone abscisic acid (ABA) reduces that loss; iCB mimics that signal and reinforces the response, moderating perspiration when it's most needed.
In addition to limiting water consumption, the molecule helps maintain the photosynthetic machinery in good condition and facilitates recovery after drought. This effect is accompanied by the activation of genes linked to protective compounds, such as proline and raffinose, which help stabilize plant cells.
A key aspect is that it does not require genetic modification of the treated plants. Unlike previous approaches—such as iSB09, designed for transgenic lines—iCB is applied to conventional crops, which reduces potential regulatory and social barriers without sacrificing efficacy.
Development of the molecule and scientific basis
The compound was designed with advanced techniques of molecular design and X-ray crystallography commonly used in drug discovery. This optimized their fit to the ABA receptors present in different species, from Arabidopsis thaliana —laboratory model— until tomato plants.
iCB is able to activate the three subfamilies of receptors of ABA, broadening the scope of the response. This includes root effects, such as hydrotropism (growth towards humid areas) and protection against drought conditions in the root system.
Crop results and potential uses
In tomato trials, foliar application allowed plants to tolerate severe droughts and resume photosynthesis after stress, maintaining production within parameters compatible with normal agricultural management.
The first tests in wheat and vine indicate activity in other crop plants. In germination tests, iCB showed greater potency than ABA, which could be used to prevent premature sprouting in cereals before harvesting, a common problem with late rains.
Its use is compatible with common spraying techniques, which facilitates adoption on farms. Researchers point out that, in extreme scenarios, the compound can help keep crops alive until irrigation is restored, fitting in as a timely management tool during critical periods.
Equipment and transfer
The work has been co-directed by Pedro L. Rodríguez (IBMCP, CSIC-UPV) and Armando Albert (IQF-CSIC). The team emphasizes that the molecule not only regulates transpiration, but also activates adaptation to water stress involved in cellular protection, a double front that explains their performance in controlled fields.
The iCB patent is shared by GalChimia, the CSIC and the UPV, and the project has collaborations with the University of Santiago de Compostela and the University of Tartu (Estonia). The next steps include validations on a larger scale and in different agroclimatic contexts to fine-tune doses, application times and target crops.
With a formulation that replicates the ABA signal without altering the genome, this approach offers a practical way for tomatoes and other crops to increase their resilience to drought, keeping photosynthesis operational and adding management options in an increasingly demanding agricultural landscape.
