Membrane trafficking and autophagy in pathogen-triggered cell death and immunity

Plants respond to pathogen attack with dynamic rearrangements of the endomembrane system and rapid redirection of membrane traffic to facilitate effective host defence. Mounting evidence indicates the involvement of endocytic, secretory, and vacuolar trafficking pathways in immune receptor activation, signal transduction, and execution of multiple defence responses including programmed cell death (PCD). Autophagy is a conserved intracellular trafficking and degradation process and has been implicated in basal immunity as well as in some forms of immune receptor-mediated vacuolar cell death. However, the regulatory interplay of autophagy and other membrane trafficking pathways in PCD and defence responses remains obscure. This review therefore highlights recent advances in the understanding of autophagic and membrane trafficking during plant immunity, and discusses emerging molecular links and functional interconnections.