Do you know plants can smell; Yes, researchers know how

New Delhi : Unlike human beings, plants don't have nose to smell. They have this inherent ability in their genes. A team of researchers at the University have discovered how information from odour molecules changes gene expression in plants. The study of plants odour detection systems may lead to new ways of influencing plant behaviour. 

The discovery is meant to reveal the molecular basis of odor detection in plants and researchers tool more than 18 years in making it.

"We started this project in 2000. Part of the difficulty was designing the new tools to do odor-related research in plants," said Professor Kazushige Touhara of the University of Tokyo.

Researchers say that plants detect a class of odour molecules known as volatile organic compounds, which are essential for many plant survival strategies, including attracting birds and bees, deterring pests, and reacting to disease in nearby plants. These compounds also give essential oils their distinctive scents. They discovered that odour molecules change gene expression by binding to other molecules called transcriptional co-repressors that can turn genes on or off.

In case of plants, the molecules of odour must move into the cell and accumulate before they affect plant behaviour. In animals, odour molecules are recognised by receptors on the outside of cells in the nose and immediately trigger a pathway to recognise the odour and change behaviour.

"Plants can't run away, so of course they react to odours more slowly than animals. If plants can prepare for environmental change within the same day, that is probably fast enough for them," said Touhara.

"Humans have about 400 odour receptors. Elephants have about 2,000, the largest number in animals. But based on how many transcription factor genes are in plants, plants may be able to detect many more odours than animals," said Touhara.

The team believe that these discoveries will influence crop quality or character without the complications of gene editing or pesticide use. Farmers could spray their fields with an odour associated with desired plant behaviour. For example, an odour triggers plants to change the taste of their leaves to deter insects.

"All creatures communicate with odour. So far, our lab has studied within-species communication: insect to insect, mouse to mouse, human to human. This understanding of how plants communicate using odour will open up opportunities to study 'olfactory' communication between all creatures," said Touhara.

The University of Tokyo research team made their discoveries using tobacco plants, a common model organism. They expect research teams around the world will soon verify the discovery in many other types of plants.