Wound-response jasmonate dynamics in the primary vasculature

Area of Science:

• Plant Biology
• Molecular Biology
• Biochemistry

Background:

• The connection between electrical signaling during wound response and jasmonate synthesis activation is not well understood.
• Jasmonates are crucial plant hormones involved in defense against herbivores and pathogens.

Purpose of the Study:

• To investigate how wound-induced electrical signals remodel jasmonate precursor pools in Arabidopsis thaliana leaf vasculature.
• To identify the enzymes responsible for regulating jasmonate precursor levels in plant veins.

Main Methods:

• Utilized MS-based metabolomics and NMR to analyze galactolipids and jasmonate precursors in Arabidopsis thaliana leaf veins.
• Identified DAD1-LIKE LIPASEs (DALLs) involved in controlling jasmonate precursor levels.
• Investigated the function of DALL2 and DALL3 in jasmonate synthesis and signaling.

Main Results:

• Discovered a novel galactolipid, sn-2-OPDA-MGMG, containing the jasmonate precursor 12-oxo-phytodienoic acid (OPDA) in plant veins.
• Observed rapid reduction of vascular OPDA-MGMGs and free OPDA pools in response to damage-activated electrical signals.
• Demonstrated that dall2 mutants exhibit impaired resting OPDA pools and reduced jasmonoyl-isoleucine (JA-Ile) production upon wounding, while DALL3 suppresses excess JA-Ile.

Conclusions:

• Electrical signal-dependent lipid phase changes in the vasculature likely initiate jasmonate synthesis in wounded Arabidopsis leaves.
• LOX6 and DALL2 are key in producing OPDA and sn-2-OPDA-MGMG in vascular tissues.
• DALL2 and DALL3 play critical roles in regulating jasmonate signaling pathways during plant wound response.