A Scanning Electron Microscopy Technique for Viewing Plant-Microbe Interactions at Tissue and Cell-Type Resolution

Area of Science:

• Plant Pathology
• Microscopy
• Molecular Biology

Background:

• Understanding plant pathogen interactions requires high-resolution imaging of pathogen localization within plant tissues.
• Current high-resolution microscopy is time-consuming and expensive, hindering efficient pathogen identification.
• A need exists for methods to rapidly locate pathogen colonization before high-resolution analysis.

Purpose of the Study:

• To introduce paraffin scanning electron microscopy (PSEM) as an efficient technique for plant-pathogen interaction studies.
• To demonstrate PSEM's ability to facilitate high-resolution imaging of specific plant cell types during infection.
• To validate PSEM's utility across diverse plant-pathogen systems.

Main Methods:

• Paraffin-embedded plant samples were sectioned to identify regions of interest.
• Identified blocks were recut, deparaffinized, and imaged using scanning electron microscopy (SEM).
• PSEM was applied to Fusarium oxysporum f. sp. lycopersici in Solanum pimpinellifolium, and other pathosystems.

Main Results:

• PSEM successfully identified pathogen colonization sites within plant tissues.
• High-resolution SEM images revealed specific plant-pathogen interactions at the cellular level.
• Fusarium oxysporum f. sp. lycopersici colonization was observed to be restricted in resistant Solanum pimpinellifolium.
• PSEM proved effective in maize and Arabidopsis pathosystems involving Clavibacter michiganensis and Pseudomonas syringae.

Conclusions:

• PSEM offers an efficient workflow for locating and imaging plant-pathogen interactions.
• The technique provides high-quality, low-noise images, enhancing understanding of pathogen virulence.
• PSEM is a versatile method applicable to various plant pathology research scenarios.