Biochemical controls: plant wound signals (Introduction)

by David Turell , Saturday, October 22, 2022, 16:57 (413 days ago) @ David Turell

How plants signal damage:

https://phys.org/news/2022-10-science-register-trauma-precursor-calcium.html

"John Innes Center researchers have shown that calcium waves are not a primary response, but rather they are a secondary response to a wave of amino acids released from the wound.

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"It has been observed for many years that wounding, and other trauma, initiates calcium waves that travel both short distances from cell to cell, and longer distances from leaf to leaf.

"These calcium waves are reminiscent of signaling seen in the nerves in mammals, but since plants do not have nerve cells, the mechanism by which this happens has been in question.

The new findings, which appear in Science Advances, suggest that when a cell is wounded, it releases a wave of glutamate, an amino acid. As this wave travels through plant tissues, it activates calcium channels in the membranes of the cells it passes. This activation appears like a calcium wave but is a passive response, or "readout'' of the moving glutamate signal.

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"Dr. Faulkner's group specializes in the study of plasmodesmata, the channels or bridges that connect cells and the team speculated that a wound signal would travel from cell to cell through plasmodesmata. However, using quantitative imaging techniques, data modeling and genetics they found that the mobile signal is a glutamate wave that travels outside of cells, along the cell walls.

""The glutamate and calcium waves are connected—glutamate triggers the calcium response. You could imagine it with an analogy of a corridor. The glutamate rushes down the corridor and as it passes a door it kicks it open. The calcium response is the door opening. Up to now the assumption has been that what moved down the corridor was hydraulic pressure or a series of propagating chemical reactions, but our study shows that this is not the case," said Dr. Faulkner."

Comment: a different way to spread information without nerves.