Plant Roots' Glutamate Sensor: A Surprising Splice Variant

When plants like Arabidopsis encounter L-glutamate at their root tips, it causes significant changes in their root structure. But how they sense this amino acid is a mystery. Scientists know that GLUTAMATE RECEPTOR-LIKE (GLR) proteins act as channels that let calcium in when they detect amino acids, playing important roles in plant growth and development. To find out if GLRs are involved in the root's response to L-glutamate, researchers looked at plants with mutations in each of the 20 GLR genes. They found that one gene, GLR2.5, was important for this response. Interestingly, GLR2. 5 produces four different messenger RNAs that could make proteins of different sizes. One of these, GLR2. 5c, makes a short protein missing key parts. When this short protein was put back into plants missing GLR2. 5, they regained their sensitivity to L-glutamate and the calcium currents it triggers. This suggests that GLR2. 5c might help other GLR proteins work together to control the root's response to L-glutamate.