Salicylic acid induces a cytosolic Ca²⁺ elevation in yeast

Cytosolic free calcium ion concentration ([Ca²⁺]_cyt) after a salicylic acid (SA)-stimulus was monitored in cells of the yeast Saccharomyces cerevisiae expressing apoaequorin, which constitutes a Ca²⁺-sensitive luminescent protein, aequorin, when combined with coelenterazine. SA induced a transient [Ca²⁺]_cyt elevation that was dependent on the concentration of SA and pH of the SA solution. The SA-induced [Ca²⁺]_cyt elevation was not reduced in Ca²⁺-deficient medium, suggesting that Ca²⁺ was mobilized from an intracellular Ca²⁺ store(s). Benzoic acid, butyric acid and sorbic acid did not induced a [Ca²⁺]_cyt elevation.