Researchers in China have found that increasing the activity of a tomato gene helped plants survive and recover from drought in controlled experiments.
The gene, known as SlbHLH70, appears to help coordinate two important parts of the plant’s response to water shortages: its internal stress signals and the growth of its roots.
The discovery could provide a useful target for future efforts to develop tomatoes that cope better with dry conditions. However, the research remains at an early stage. It was conducted in growth chambers using a research tomato variety, rather than commercial plants growing in fields.
Testing the gene’s role
SlbHLH70 is a transcription factor. This means it produces a protein that helps control the activity of other genes.
To investigate its role, the researchers created tomato plants that produced much more SlbHLH70 than usual. They also used CRISPR gene editing to create separate plants in which the gene no longer worked properly.
The results showed a clear difference in how the plants responded to a lack of water.
In one experiment, the plants were left without watering for 14 days. After four days of recovery, around 60% of the plants producing extra SlbHLH70 were still alive. Fewer than 40% of the unmodified control plants survived.
A separate experiment produced the opposite result when the gene was disabled. After 13 days without water and one day of recovery, fewer than 15% of the gene-edited plants survived, compared with approximately 35% of the control plants.
How the gene may help
The researchers found evidence that SlbHLH70 influences a plant hormone called abscisic acid, or ABA. Plants use ABA to organize some of their responses to dry conditions.
During drought, plants producing extra SlbHLH70 had higher ABA levels than the control plants. Plants without a working copy of the gene had lower levels.
The gene also affected root development. Under dry conditions, plants producing extra SlbHLH70 developed longer and heavier roots. Plants in which the gene had been disabled showed weaker root growth.
The researchers did not directly measure how much water the different plants absorbed. However, stronger root growth could help a plant continue obtaining water as the soil becomes dry.
Genetic analysis also identified 151 drought-responsive genes that may be directly regulated by SlbHLH70. The researchers confirmed interactions with selected genes involved in ABA signaling and root development.
A possible target for crop improvement
The results suggest that SlbHLH70 is not responsible for just one drought-protection mechanism. Instead, it helps connect several parts of the plant’s response, including hormone signaling and root growth.
That could make the gene useful in future tomato-breeding or gene-editing research. Changing one regulatory gene may allow researchers to influence several drought-related processes at the same time.
There are still important questions to answer. The experiments used the Micro-Tom tomato variety under controlled conditions. The researchers did not test commercial varieties in fields or measure fruit yield and quality.
Further studies will therefore be needed to determine whether changing SlbHLH70 can produce useful benefits on farms without affecting other important characteristics.
For now, the research provides a promising lead rather than a drought-resistant tomato that is ready for commercial production.
Sources
- Li, A. et al. (2026). “Transcription factor SlbHLH70 enhances drought tolerance in tomato.” Horticulture Research, 13(6), uhag075.
- PubMed record for the study
