Did you know that plants have been making aspirin for millions of years? And humans have been using it as far back as Neanderthal times for self-medication? The pain medication can be found in trees and sunflowers alike in an unprocessed form called salicylic acid, created in response to when a plant is experiencing stress.

A group from UC Riverside conducted a study to find out more about this phenomenon, with the hopes of applying this to improve plants’ survival chances against climate change. “We’d like to be able to use the gained knowledge to improve crop resistance,” explained co-first author Jin-Zheng Wang. “That will be crucial for the food supply in our increasingly hot, bright world.”

The experiments were carried out on the plant species Arabidopsis, which was exposed to intense light. This environmental stressor resulted in the formation of reactive oxygen species (ROS), which can be extremely damaging for the plant in high numbers. However, low levels of ROS have an important role in plant cell functioning. “At non-lethal levels, ROS are like an emergency call to action, enabling the production of protective hormones such as salicylic acid. ROS are a double-edged sword, ” Wang said.

The team found that low levels of ROS triggered the production of the alarm molecule MEcPP, then promoted salicylic acid production. Further reactions then follow in the plant cells that protect the organisms’ chloroplasts, the vital sight of photosynthesis. This chain of reactions was found in plants in response to heat, unabated sunlight, and drought, showing plants use painkillers for various aches and pains just like humans!

“Because salicylic acid helps plants withstand stresses becoming more prevalent with climate change, being able to increase plants’ ability to produce it represents a step forward in challenging the impacts of climate change on everyday life,” said senior author Katayoon Dehesh.

They continue: “Those impacts go beyond our food. Plants clean our air by sequestering carbon dioxide, offer us shade, and provide habitat for numerous animals. The benefits of boosting their survival are exponential.”

Further research will be carried out by the group centered around the role of MEcPP, a molecule produced also in other organisms such as bacteria and malaria parasites.

Source study: Science – Reciprocity between a retrograde signal and a putative metalloprotease reconfigures plastidial metabolic and structural states