Live Single-Cell Plant Hormone Analysis by Video-Mass Spectrometry

Area of Science:

• Plant Physiology
• Analytical Chemistry
• Molecular Biology

Background:

• Plant hormone concentrations are regulated locally within plant tissues.
• Understanding cellular hormone levels is crucial for deciphering hormone-mediated physiological processes.

Purpose of the Study:

• To establish a system for quantifying abscisic acid (ABA) and jasmonoyl-isoleucine (JA-Ile) levels at the single-cell level.
• To enable monitoring of plant stress responses at cellular resolution.

Main Methods:

• Development of a single-cell sampling technique using nano-electrospray ionization (ESI) tips under microscopy.
• Direct infusion of single-cell samples into tandem mass spectrometry (MS/MS) for analysis.
• Utilizing stable isotope-labeled internal standards ([D(6)]ABA and [(13)C(6)]JA-Ile) to ensure accurate quantification.

Main Results:

• Successfully detected and quantified ABA and JA-Ile in single cells from water- and wound-stressed Vicia faba leaves.
• Hormone levels were found to be significantly lower in non-stressed single cells.
• Single-cell measurements were validated against traditional liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of bulk extracts.

Conclusions:

• The developed method allows for the monitoring of stress-induced accumulation of ABA and JA-Ile in living single plant cells.
• This technique provides unprecedented spatial resolution for studying plant hormone dynamics.
• The findings open new avenues for investigating localized hormone signaling in plants.