A study led by the University of Maryland explains how plants communicate within cells using a protein that closely resembles an animal protein that has a role in communication between nerve cells. While plants lack a true nervous system, previous studies have shown that plants need these proteins, called glutamate receptor-like proteins (GLRs), to do important things such as mate, grow, and defend themselves against diseases and pests. In the study, researchers working with pollen cells from Arabidopsis thaliana found that these GLR proteins form the basis of a complex communication network inside individual plant cells. The similarities between the animal nerve proteins (glutamate receptors) and the GLR plant proteins suggest that the two proteins date back to a common ancestor—a single-celled organism that gave rise to both animals and plants. Research findings suggest that GLRs rely on another group of proteins, called "cornichon" proteins, to transport GLRs to different locations in plant cells and to regulate activity of the protein within each cell. The study found that with the help of cornichon proteins, GLRs act as valves that carefully manage the concentration of calcium ions—a vital aspect of many cell communication pathways—within various structures inside the cell. (Source: Agriculture and Food News, ScienceDaily. www.sciencedaily.com) At left, normal Arabidopsis thaliana plants reproduce when pollen tubes (thin blue filaments) grow downward toward the ovules to produce seeds. At right, in a plant with a mutated glutamate receptor-like protein gene, this process happens much more slowly. Arrows in both images mark the advance of the pollen tubes at exactly the same time after pollination.