An international group of researchers discovered defense signaling in plants that is triggered by glutamate
Although plants do not have brains, they have a nervous system. Now, a joint research by botanists at Saitama University, Japan, University of Missouri, University of Wisconsin, and Michigan State University found that when a leaf gets eaten, it warns other leaves by using some of the same signals as animals. The research published in the journal Science on September 14, 2018 uncovers the long-standing mystery about communication in different parts of a plant.
In animals, nerve cells communicate with each other with the help of glutamate, an amino acid. The acid is released by an excited nerve cell and it aids to set off a wave of calcium ions in adjacent cells. The wave relays a signal to the next one in line by traveling down the next nerve cell. This in turn enables long-distance communication in animal nerve cells. The team initial purpose was to investigate plants reaction to gravity. As the team proposed role of calcium in this interaction, a molecular sensor was developed to detect increase in calcium. They bred the sensor into a mustard plant called Arabidopsis. The sensor glows brighter as calcium levels increase.
A leaf of the plant was cut to detect any calcium activity. This resulted in a bright glow right next to the wound that later got dimmer. The glow later appeared and disappeared farther away until the wave of calcium reached the other leaves. Further study revealed that glutamate triggered the calcium wave in the plants. Although it is proved by previous research that changes to one part of a plant are sensed by the others, the mechanism behind the information transmission was not understood. However, the current research revealed that calcium wave and glutamate can help better monitor and manipulate the plant’s internal communications.