“It is indeed true that plants can and do communicate with each other frequently,” Pertot begins. “And plants can talk to all other plants, they’re not just limited to conversation with plants of the same species.” Plants don’t use vibrations to communicate as insects and other organisms do. Instead, they release volatile organic compounds (VOCs), a type of scent called a kairomone, from their flowers, leaves and roots. Each compound is different, but they provide signals to nearby plants and other organisms to provide specific information or to warn them of a possible attack. “If an insect is feeding on a plant’s leaves, that plant will release specific VOCs to warn other plants nearby. If a human decides to callously snap a piece of a plant off, then again, the plant releases its warning to all nearby plants of the potential danger,” Pertot continues. “Obviously a plant can’t get up and run away, so the emphasis is all on defence.” Defence can take the form of a physical reaction, such as the strengthening of the cell walls to provide a stronger, more robust barrier, or a chemical reaction that produces toxic compounds to deter herbivores and pathogens. In fact, plants even communicate with non-plant species as well, such as the microorganisms around them. Plants intentionally send signals from their roots into the soil to attract certain microorganisms that are beneficial for their growth and development – essentially, an invitation to ‘good’ microbiota to move into the plant as a human would move into a new apartment. The plant benefits in numerous ways when the right tenants move in. They contribute to plant protection, can help regulate the production of cells and hormones, and can facilitate the growth of roots, so that the plant can explore a wider area of soil.
Learning the secret language of plants
Pertot and her colleagues hope to practically harness the plant communication process to increase plant resilience, a key element of the EU-funded RhizoTalk project that she worked on. “We’re rapidly developing the molecular tools to understand plant communication, and we do this by monitoring the plant’s gene expressions,” she explains. “It’s essentially like decoding a language. The plant’s genes act as a sort of Rosetta Stone to help guide us.” Once Pertot and her colleagues know the molecular pathway for the production of VOCs, they hope to crack the secret language of plants. Once fluent, scientists could feasibly direct the plant communication process to, for example, better protect them from parasites. Just a slight modification to the plant’s DNA would mean that a parasite wouldn’t be able to recognise the plant as a viable host. That would render pesticides obsolete. “Alongside increasing resilience, the processes behind plant communication could also feasibly provide natural alternatives for many chemically synthesised molecules used to manufacture paints and detergents, alongside pesticides. This will be a big ambition of ours over the next 10 years,” Pertot concludes. So there you have it. Your next walk in the forest may sound tranquil to your ears, but now you know that it’s anything but – the trees may even be talking about you. Click here to find out more about Ilaria Pertot’s research: Soil holds secrets to greener pest management.
RhizoTalk, plants, volatile organic compounds, VOCs, gene expression, microbiota