Plants adjust a “chemical code” to cope with climate change

Lignin is a complex organic polymer which forms key structural materials in the support tissues of plants. This substance allows plants to conduct water and stand upright, and plays a fundamental role in the formation of cell walls, particularly in wood and bark. 

According to a new study led by Stockholm University, it is possible to create and/or select plants that can better recover from droughts without affecting the plants’ size or seed yield by genetically modifying their lignin chemistry. These findings could be applied in both agriculture and forestry to tackle climate change-related challenges.

“Plants are made of many different cells, some of them are reinforced with lignin and assemble to each other to form a pipe that conducts water, like a straw to drink your cocktail,” said study lead author Delphine Ménard, an expert in Plant Sciences at Stockholm University. 

For a long time, scientists believed that lignin does not have a “code” like DNA or proteins. However, Dr. Ménard and her colleagues have now challenged this old paradigm, by showing that each plant cell uses a chemical code to adjust their lignin to function optimally and cope with environmental stressors. This important finding could have major applications in agriculture and forestry.

“It takes only one simple chemical change, just one hydrogen atom apart from alcohol to aldehyde to make plants highly resilient to drought in conditions where alcohol-rich plants would all die,” said study senior author Edouard Pesquet, an associate professor of Molecular Plant Physiology at Stockholm.

Interestingly, such large increases of lignin aldehydes can also occur naturally in the wild. For instance, mulberries with the highest lignin aldehyde levels are more frequently used by silk caterpillars across Japan. 

“These results revise our understanding of lignin and plant water conduction, but also open great possibilities to use the lignin code to improve crops and trees to face water availability problems. The modification of lignin chemistry at the single cell level is ultimately the mechanism enabling plants to grow, hydrate, and resist climate change stresses,” Professor Pesquet concluded.

The study is published in the journal The Plant Cell. 

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By Andrei Ionescu, Earth.com Staff Writer