Quantification of Cell-to-Cell Connectivity Using Particle Bombardment

Area of Science:

• Plant Cell Biology
• Molecular Biology
• Biophysics

Background:

• Plant cells possess plasmodesmata, membrane-lined cytoplasmic channels connecting adjacent cells.
• These channels facilitate cell-to-cell transport of molecules, regulated by their aperture size.
• Molecular size influences passive movement, with larger molecules experiencing more restricted passage.

Purpose of the Study:

• To establish a method for assessing plasmodesmal aperture using Green Fluorescent Protein (GFP).
• To quantify functional cell-to-cell connectivity in plant tissues.
• To present robust methods for microprojectile bombardment and data analysis.

Main Methods:

• Utilizing Green Fluorescent Protein (GFP), a 27 kDa soluble protein, as a tracer molecule.
• Employing microprojectile bombardment for transgenic GFP production in single leaf epidermal cells.
• Quantifying GFP cell-to-cell mobility via live-cell imaging and counting fluorescent cells/layers.

Main Results:

• GFP's passive cell-to-cell movement through plasmodesmata serves as a reliable indicator of aperture.
• The number of cells exhibiting GFP fluorescence directly correlates with plasmodesmal aperture and connectivity.
• Developed statistical methods for analyzing GFP mobility data.

Conclusions:

• Microprojectile bombardment of GFP is an effective method for assessing plasmodesmal aperture.
• GFP mobility provides a quantitative measure of functional cell-to-cell communication in plants.
• The presented methods enable precise evaluation of plasmodesmal function.