Protein and membrane trafficking routes in plants: conventional or unconventional?

The conventional trafficking of proteins, membranes and metabolites between membrane-bound compartments in the cell uses highly conserved pathways. However, this does not always account for the way some cargo are sorted to their final destination, and ongoing research is focused on defining these 'unconventional' routes and investigating their purpose. In this special issue, a collection of reviews discusses the current literature in this field, proposing thought-providing mechanistic models, and exploring where these unconventional trafficking pathways are employed, from basic cellular functions to plant-microbe interactions.