Biologists May Have Solved a 30-Year-Old Mystery on Why Touch Stresses Plants Out

Scientists have known for a long time that touching plants can cause a stress reaction in them, but until now they have not been able to explain how that works at a molecular level.

The researchers behind the study have identified certain genetic keys inside plants that lead to two different signaling pathways.

Understanding more about how this process works at a fundamental level could help researchers in a variety of different areas, from improving plant health to getting higher harvest yields from the same crop.

After exposing the plant thale cress to soft brushing, thousands of genes were activated and stress hormones were released.

We used genetic screening to find the genes that were responsible for this process.

The genetic screening looked for forms of the plant that respond differently to physical touches. Research on their roots indicated that special channels in the cell were able to facilitate chemical signals.

It was not known how this process worked in other parts of the plant. There were hints that compounds like jasmonic acid played a critical role in transforming early chemical signals into behavioral or growth changes, but there were also plenty of gaps that needed to be filled.

The researchers found six genes that played a role in touch response, three for the signaling pathway related to jasmonic acid, and three on a separate signaling pathway.

That gives biologists a lot more to work with when it comes to understanding how and why this response happens and how we can potentially manipulate it in the future.

"Our results solve a scientific mystery that has evaded the world's molecular biologists for 30 years," says biologist Essam Darwish from Lund University.

We have identified a completely new signaling pathway that controls a plant's response to touch and physical contact. The search for more paths continues.

Every touch that a plant gets leads to a defensive response, although these responses can be quite varied. Plants can become more stress-resistant and flowering later in the year if they are led to by them.

Scientists are already looking into how carefully managed mechanical wounding can make for sturdier crops and harvests that are more plentiful, because the plants build up more of a resistance to stress.

Climate change is putting even more pressure on agriculture and wheat production, and this latest research gives scientists vital information about how this is all controlled.

Given the extreme weather conditions and pathogen infections that climate change leads to, it is of paramount importance to find new ecologically responsible ways to improve crop productivity and resistance.

Science Advances has published the research.