Abstract
12-oxo-phytodienoic acid (OPDA) is not only an intermediate in jasmonic acid biosynthesis pathway, but also regulates gene expressions as an oxylipin signaling molecule that differ from jasmonic acid. However, the signaling mechanism of OPDA is largely unknown. In this study, to reveal the OPDA signaling mechanism, we analyzed transcriptional responses of OPDA-specific response genes, HsfA2 and DREB2A, in the presence of a protein synthesis inhibitor cycloheximide (CHX) and a HSP90 inhibitor geldanamycin (GDA).
HsfA2 and DREB2A expressions were markedly increased by co-treatment with OPDA and CHX, although these expressions were slightly induced by respective treatment of OPDA or CHX. In addition, these expressions were transiently induced by OPDA and/or GDA, with distinct expression profiles observed in co-treatment of OPDA and CHX. These results suggest that the OPDA-mediated expressions of these genes are suppressed by HSP90. Furthermore, other unknown protein factor(s) may also suppress their sustained expressions.
