Long-standing theories about how plants rely on calcium waves to respond systemically to injury and other stresses have been given a new perspective. Phys.org portal.
John Innes Center researchers have shown that calcium waves are not a primary, but rather a secondary response to a wave of amino acids released from the wound.
These calcium waves resemble signals seen in mammalian nerves, but the mechanism by which this occurs has not been studied.
New results published in Science Advances, suggest that when a cell is injured, it emits a wave glutamate. When this wave travels through plant tissue, it activates calcium channels in the membranes of the cells it passes through. This activation looks like a calcium wave, but is a passive response or "readout" of the moving glutamate signal.
Dr. Faulkner's group specializes in the study of plasmodesmata, the channels that connect cells. The scientists hypothesized that the signal from the wound would be transmitted from cell to cell via plasmodesmata. However, using quantitative imaging techniques, data modeling and genetics, they found that the mobile signal is a glutamate wave that propagates outside the cells, along the cell walls.
Calcium waves are synchronous with glutamate waves, and their dynamics correspond to transmission by diffusion.