Quantitative changes in microtubule distribution correlate with guard cell function in Arabidopsis

Area of Science:

• Plant Cell Biology
• Plant Physiology
• Cytoskeleton Dynamics

Background:

• Cortical microtubules are radially arranged in guard cells, playing a role in stomatal function.
• Previous research indicated changes in microtubule appearance during stomatal opening and closing.

Purpose of the Study:

• To investigate the specific changes in microtubule organization and dynamics within guard cells during stomatal aperture changes.
• To determine if microtubule bundling or growth is responsible for altered tubulin polymerization.

Main Methods:

• Confocal microscopy of guard cells expressing GFP-tubulin (GFP-TUA6) and RFP-tagged EB1.
• Analysis of fluorescence distribution to quantify microtubule peak intensities and total polymerized tubulin.
• Comparison of guard cells with adjacent pavement cells.

Main Results:

• A significant increase in microtubule bundle peak intensities and total polymerized tubulin was observed in open stomata compared to closed stomata.
• No similar changes were detected in adjacent pavement cells.
• The number of growing microtubule ends (visualized with EB1) remained constant, indicating bundling rather than de novo growth.

Conclusions:

• Stomatal opening involves increased microtubule bundling or clustering within guard cells.
• These microtubule organization changes are crucial for normal guard cell function and stomatal movement.
• The findings highlight the dynamic nature of the plant cytoskeleton in response to physiological stimuli.