Methods for measuring plant cytoplasmic calcium using micro-electrodes or microinjected fluorescent dyes are associated with extensive technical problems, so measurements have been limited to single or small groups of cells in tissue strips or protoplasts1. Aequorin is a calcium-sensitive luminescent protein from the coelenterate Aequorea Victoria (A. forskalea) which is formed from apoaequorin, a polypeptide of relative molecular mass ~ 22,000, and coelenterazine, a hydrophobic luminophore. Microinjected aequorin has been widely used for intracellular calcium measurement in animal cells, but its use in plants has been limited to exceptionally large cells. We show here that aequorin can be reconstituted in transformed plants and that it reports calcium changes induced by touch, cold-shock and fungal elicitors. Reconstituted aequorin is cytoplasmic and nonperturbing; measurements can be made on whole plants and a calcium indicator can be constituted in every viable cell. Now that apoaequorin can be targeted to specific organelles, cells and tissues, with the range of coelenterazines with differing calcium sensitivities and properties available, this new method could be valuable for determining the role of calcium in intracellular signalling processes in plants.

Item Type:	Refereed Article
Keywords:	Aequorea victoria, transgenic, cytoplasmic calcium, aequorin
Research Division:	Biological Sciences
Research Group:	Plant biology
Research Field:	Plant physiology
Objective Division:	Expanding Knowledge
Objective Group:	Expanding knowledge
Objective Field:	Expanding knowledge in the biological sciences
UTAS Author:	Smith, SM (Professor Steven Smith)
ID Code:	101596
Year Published:	1991
Web of Science® Times Cited:	921
Deposited By:	Plant Science
Deposited On:	2015-06-26
Last Modified:	2015-12-07
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