12-Oxo-Phytodienoic Acid–Glutathione Conjugate is Transported into the Vacuole in Arabidopsis

Abstract

While exogenous toxic compounds such as herbicides are thought to be sequestered into vacuoles in the form of glutathione (GSH) conjugates, little is understood about natural plant products conjugated with GSH. To identify natural products conjugated with GSH in plants, metabolites in the Arabidopsis g-glutamyl transpeptidase (ggt) 4 knockout mutants that are blocked in the degradation of GSH conjugates in the vacuole were compared with those in wild-type plants. Among the metabolites identified, one was confirmed to be the 12-oxo-phytodienoic acid (OPDA)-GSH conjugate, indicating that OPDA, a precursor of jasmonic acid (JA), is transported into the vacuole as a GSH conjugate.

Lotus japonicus nodulation is photomorphogenetically controlled by sensing the red/far red (R/FR) ratio through jasmonic acid (JA) signaling

“…After 12 d, plants were inoculated with M. loti (1.0 × 10 7 cells/plant), and then, plants were quick frozen in liquid N 2 7 DAI (day 22). The endogenous concentration of JA and JA-Ile was measured by the method previously reported (40).…”

The metabolomics of oxidative stress

“…Oxylipin signalling involves a cyclophilin that, on binding 12-oxo-phytodienoic acid (OPDA), activates cysteine synthesis to modulate cell thiol status (Park et al, 2013). Another interaction with glutathione involves possible regulation of OPDA signalling intensity by formation of S-conjugates (Ohkamu-Ohtsu et al, 2011). Camalexin accumulation also draws on the glutathione pool, as its sulfur atom is derived from this key intracellular thiol (Su et al, 2011).…”

“…Like GSH conjugation via GST action, the introduction of a sugar tag enables recognition by transporters, notably located on the tonoplast. Also like GSTs, CYP and UGT functions extend beyond metabolism of xenobiotics, and include synthesis of secondary metabolites and regulation of secondary signalling molecules produced by ROS-dependent reactions, including phytohormone-related molecules like SA and OPDA (Lim et al, 2002;Ohkamu-Ohtsu et al, 2011;Su et al, 2011;Farmer and Mueller, 2013). At least two CYPs are induced >10-fold in cat2 (Fig.…”

Basic Helix-Loop-Helix Transcription Factors JASMONATE-ASSOCIATED MYC2-LIKE1 (JAM1), JAM2, and JAM3 Are Negative Regulators of Jasmonate Responses in Arabidopsis

“…JArelated molecules were extracted and quantified as described in previous reports with slight modification (Yoshimoto et al, 2009;Ohkama-Ohtsu et al, 2011). After grinding with 10-mm zirconia beads, 1 mL of acetonitrile: added to 1 mg dry weight of unwounded Arabidopsis aerial part and extracted for 1 h. A 100 times larger amount of each stable isotope-labeled chemical was added for wounded plant materials.…”