The effects of Group 11 transition metals, including gold, on ethylene binding to the ETR1 receptor and growth of Arabidopsis thaliana.

It has been previously shown that Cu(I) and the ethylene response antagonist, Ag(I), support ethylene binding to exogenously expressed ETR1 ethylene receptors. Both are Group 11 transition metals that also include gold. We compared the effects of gold ions with those of Cu(I) and Ag(I) on ethylene binding in exogenously expressed ETR1 receptors and on ethylene growth responses in etiolated Arabidopsis seedlings. We find that gold ions also support ethylene binding but, unlike Ag(I), do not block ethylene action on plants. Instead, like Cu(I), gold ions affect seedlings independently of ethylene signaling.