Abstract
Jasmonates are widely distributed among higher plants and play a role in plant growth and stress response. We isolated (-)-12-O-β-D-glucopyranosyl jasmonic acid as the biologically active substance, leaf-closing factor ((-)-LCF), which induced nyctinastic leaf movement of Samanea saman and we reported that (-)-LCF binds to extensor motor cells in pulvini. In the nyctinastic leaf closure, extensor cell shrinks and flexor cell swells. Therefore, to investigate the correlation of specific recognition of jasmonate derivatives and nyctinastic movement, we prepared protoplast from pulvini and treated with jasmonate derivatives. As we expected, (-)-LCF decreased the volume of extensor cell, while other jasmonate derivatives did not induce cell shrinkage. Moreover, addition of K channel and Ca channel inhibitors repressed the cell shrinkage. To investigate the relevance of LCF and JA signaling pathway, we employed Arabidopsis thaliana harboring JA responsive pLOX2::GUS. JA activated pLOX2::GUS, whereas (-)-LCF was inactive. These study indicate that nyctinastic movement are unique property of (-)-LCF and imply the existence of COI1-JAZ independent signaling pathway for lead closure.
