Using Microscopy Tools to Visualize Autophagosomal Structures in Plant Cells.

Macroautophagy (hereafter as autophagy), is a metabolic process for sequestration of cytoplasmic cargos into a double membrane structure named as autophagosome. In plants, autophagy is required for nutrition mobilization/recycling and clearance of protein aggregates or damaged organelles during starvation or other unfavorable conditions, as well as for plant immunity during pathogen infection. Multiple experimental approaches have been developed to elucidate the autophagic activity. To facilitate further investigations on the potential involvement of autophagy in protein secretion process in plant cells, here we describe detailed protocols to measure the autophagic activity in model plant Arabidopsis. Using the autophagosome marker ATG8 and a novel autophagic regulator SH3P2 as examples, we illustrate the major cell biology tools and methods using microscopy to analyze the autophagosomal structures in plant cells, including BTH-induced autophagic response, transient expression and colocalization analysis, as well as immuno-EM labeling.