A study published in Frontiers in Sustainable Food Systems shows that the fruits of a tomato variety are capable of sending electrical signals to the rest of the plant when infected by caterpillars. Plants have a multitude of chemical and hormonal signaling pathways, which are generally transmitted through sap (the nutrient-rich water that moves through the plant). In the case of fruits, the nutrients flow exclusively to the fruit and there has been little research on whether there is any communication in the opposite direction, that is, from fruit to plant.
“Usually we forget that the fruits of a plant are living, semi-autonomous parts of its mother plants, much more complex than we think. Since the fruits are part of the plant, made from the same tissues of the leaves and the stems, why not? they communicate with the plant, informing it about what they are experiencing, just as normal leaves do ”, explains Gabriela Niemeyer Reissig, from the Federal University of Pelotas, Brazil.“ What we discovered is that the Fruits can share important information, such as caterpillar attacks, which is a serious problem for a plant, with the rest of the plant, and that can probably prepare other parts of the plant for the same attack . “
The authors recall that their results are still initial. Its measurements provide a panoramic view of all electrical signals, rather than distinguishing individual signals with greater precision. It will also be interesting to see if this phenomenon applies to other plant species, as well as to different types of threats.
The tomato defense
To test the hypothesis that fruits communicate using electrical signals, Niemeyer Reissig and his collaborators placed tomato plants in a Faraday cage with electrodes at the ends of the branches that connect the fruits to the plant. They then measured the electrical responses before, during and after the Helicoverpa armigera caterpillars attacked the fruits for 24 hours. The team also used machine learning to identify patterns in the signals.
The results showed a clear difference between the signals before and after the attack. Additionally, the authors measured biochemical responses, such as defensive chemicals like hydrogen peroxide, in other parts of the plant. This showed that these defenses were activated even in parts of the plant that were far from the damage caused by the caterpillars.
“If studies like ours continue to advance and the techniques for measuring electrical signals in open environments continue to improve, it will be possible to detect the infestation of agricultural pests quite early, allowing less aggressive control measures and more precise insect management”, explains the researcher . “Understanding how the plant interacts with its fruits, and the fruits between them, can provide ideas on how to ‘manipulate’ this communication to improve fruit quality, resistance to pests and shelf life after harvest.”
