Plant mitochondrial membranes: adding structure and new functions to respiratory physiology

•Plant mitochondrial membranes act as integrators of respiration and cell physiology.•The outer membrane provides an attachment platform for auxiliary cell functions.•Form and function are tightly interconnected at the inner membrane.•Membrane fine-organisation optimizes respiration and transport.

The membranes of mitochondria are focal points of cellular physiology and respiratory energy transformation. Recent discoveries have started painting a refined picture of plant mitochondrial membranes as platforms in which structure and function have evolved in an interconnected and dynamically regulated manner. Hosting ancillary functions that interact with other mitochondrial properties gives mitochondria the characteristics of multitasking and integrated molecular mega machines. We review recent insights into the makeup and the plasticity of the outer and inner mitochondrial membranes, their intimate relationship with respiratory function and regulation, and their properties in mediating solute transport. Synthesizing recent research advances we hypothesize that plant mitochondrial membranes are a privileged location for incorporation of a wide range of processes, some of which collaborate with respiratory function, including plant immunity, metabolic regulation and signal transduction, to underpin flexibility in the acclimation to changing environments.