Plant Mitochondria

Plant mitochondria, like the mitochondria of other eukaryotes, originated from an endosymbiotic event and have retained their own genome. Over a billion years of evolution, most mitochondrial genes are laterally transferred to the nucleus. Consequently, most proteins required for mitochondrial biogenesis and activity are synthesised in the cytosol and imported via specific protein import machineries. Mitochondria are energy‐generating organelles that via electron transfer chain (ETC), create a proton gradient and generate adenosine triphosphate (ATP), the energy chemical used by the cell for numerous biochemical reactions. Energy production can come at a cost as reactive oxygen species (ROS) are generated as by‐product. Plant mitochondria have alternative ETC pathways to regulate mitochondrial ROS (mtROS) through modulating the rate of redox reactions, proton gradient and ATP production. Although excessive ROS can damage cellular components and lead to programmed cell death, mtROS also play an important role as signalling molecules. mtROS are involved in nucleus–mitochondria communications (anterograde–retrograde signalling), mitochondrial autophagy (mitophagy) and play a role in the plant response to various environmental stimuli. Considering the pivotal roles of mitochondria in energy generation and cellular signalling, perturbation of mitochondrial biogenesis and activity renders plants to be more susceptible to various stresses and ultimately compromises plant growth, development and reproduction.