Jasmonate-mediated stomatal closure under elevated CO₂ revealed by time-resolved metabolomics

Area of Science:

• Plant physiology
• Plant metabolomics
• Plant signaling

Background:

• Foliar stomatal movements regulate plant water loss and gas exchange.
• Elevated carbon dioxide (CO2) levels are known to induce stomatal closure.
• CO2 signal transduction in stomatal guard cells is not well understood.

Purpose of the Study:

• To investigate the metabolomic responses of Brassica napus guard cells to elevated CO2.
• To elucidate the signaling pathways involved in CO2-induced stomatal closure.

Main Methods:

• Utilized three hyphenated metabolomics platforms: GC-MS, LC-MRM-MS, and UHPLC-QTOF-MS.
• Quantified 358 metabolites in guard cells over a time course in response to elevated CO2.
• Analyzed JA biosynthesis and signaling mutants, and CO2 signaling mutants.

Main Results:

• Most guard cell metabolites increased under elevated CO2, with significant differences observed at 10 minutes.
• Elevated CO2 led to increased reactive oxygen species production and decreased stomatal aperture.
• Significant alterations in flavonoid, organic acid, sugar, fatty acid, phenylpropanoid, and amino acid pathways were observed.
• The jasmonic acid (JA) biosynthesis pathway was notably altered.

Conclusions:

• CO2-induced stomatal closure is mediated by jasmonic acid (JA) signaling.
• This study identifies key metabolic changes in guard cells under elevated CO2.
• Provides novel insights into the molecular mechanisms of stomatal response to rising atmospheric CO2.