Plants cannot escape environmental threats. When they face heat, drought, flooding, freezing, or infection, they must rely on internal signaling systems that help them detect stress, adjust their metabolism, and survive changing conditions.
A new Science Advances study from researchers at the Institute of Science and Technology Austria (ISTA) and international collaborators sheds light on one of these systems: the signaling molecule cAMP.
In mammalian cells, cAMP is well studied and known to play essential roles in hormone signaling, nerve-cell communication, and metabolism. In plants, however, its functions have remained much less clear, according to a press release.
The research team, led by ISTA alum Mingyue Li and professor Jiří Friml, studied cAMP in Arabidopsis thaliana, a widely used plant model also known as thale cress. They found that plants rely on two related forms of cAMP that operate in parallel: 3’,5’-cAMP and 2’,3’-cAMP.
The first form, 3’,5’-cAMP, is the dominant form in animals. In plants, it appears to help fine-tune normal cellular activities, including growth, maintenance, nutrient status, and routine metabolic regulation.
The second form, 2’,3’-cAMP, is chemically similar but arranged differently: it has the same chemical formula, but its phosphate group is attached at a different position on the adenosine molecule. In animals, this form is linked to RNA degradation and stress responses, and high levels can be harmful. In plants, however, the researchers found that 2’,3’-cAMP is far more abundant—more than 60 times higher than 3’,5’-cAMP.
Using molecular and cell biology approaches, the team showed that the two forms of cAMP have mostly distinct roles. While 3’,5’-cAMP seems to support everyday cellular regulation, 2’,3’-cAMP has broader effects, including activating specialized metabolic pathways and wider stress-response programs.
At the same time, the two pathways are not completely separate. Their functions partially overlap, and they appear to communicate with each other. This crosstalk may give plants an important advantage: redundancy. If one pathway is weakened or disrupted, the other may help compensate.
That backup system could allow plants to respond more flexibly and robustly to many kinds of environmental stress. By maintaining two parallel but interconnected cAMP pathways, plants may be better able to distinguish between different external signals and adjust their responses accordingly.
Ultimately, the findings deepen our understanding of how plants regulate both normal cell function and stress adaptation. In the long term, this knowledge could help researchers develop crops that are more resilient to climate stress while maintaining productivity.
