New research reveals copper helps plants detect hydrogen peroxide stress signals
Scientists have identified a metal-based sensing system in plant cell receptors. The Scientists from Nagoya University, in collaboration with the RIKEN Center for Sustainable Resource Science and The University of Osaka, have discovered a new way plants detect stress signals. The study was published in Nature Communications and provides important insights into plant biology.
Plants often face environmental stress and attacks from pathogens. To survive, they rely on chemical signals such as hydrogen peroxide, a reactive molecule that helps trigger defense responses. Until now, scientists believed plants detected this molecule using cysteine-based mechanisms.
However, researchers found a different system at work. A receptor in plants, known as CARD1 or HPCA1, was shown to use copper to sense hydrogen peroxide. This discovery changes how scientists understand plant stress responses.
The team identified a copper ion attached to specific parts of the receptor called histidine residues. When hydrogen peroxide is present, it interacts with this copper site. This reaction allows the plant to detect the signal and activate defense responses.
The study also showed that cysteine residues, once thought to be essential for detection, mainly help maintain the structure of the receptor. They are not directly involved in sensing hydrogen peroxide.
"The results showed that when the copper-binding site is disrupted, plants lose their ability to respond to H₂O₂ signals," said Anuphon Laohavisit, lead author and designated associate professor at the WPI-ITbM. "In contrast, mutations in cysteine residues had little effect on signaling, indicating that their primary role is structural rather than signaling."
Using computational models, researchers suggested that the detection occurs through a chemical change in copper. This change may either directly signal the plant or create other molecules that activate further responses.
The findings also indicate that plants may use a separate system to detect quinones, another important stress-related compound.
This research provides the first clear evidence of a metal-based sensing system in plant cell receptors. It opens new possibilities for improving crop resilience by better understanding how plants detect and respond to stress conditions.
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