Mitochondria and stress signalling

How does a plant sense stress and pass those signals around its body? Corentin Dourmap and colleagues have reviewed the role of mitochondria in the plant cell and how they interact with stress signalling.

The mitochondria are power generators of the cell that keep the cell running. They found throughout the plant. Their role and ubiquity makes them a key element of understanding plant stress, Dourmap and colleagues write. “Given their strong involvement in energy homeostasis, mitochondria are key organelles for plant responses to environmental stresses. Moreover, they function through an important surface of contact and strong biochemical exchanges with the cytosol, and thus, directly or indirectly, with all of the cell compartments. Environmental stresses can directly affect mitochondrial activities, thus leading to situations of mitochondrial perturbation or stress.“

The authors find that mitochondria are embedded in responses to an astonishing variety of stresses, from drought and salinity to light, toxins, herbivorous attack and pathogen attacks. This multiple role could lead to conflicting responses to one particular challenge in the future, the team say. “It can therefore be assumed that, as multi-stress signalling hubs related to energy and redox balance, mitochondria could function as integrators of multiple climate change signals and be involved in acclimation to climate change. However, involvement in such a wide range of responses also implies that mitochondrial stress signalling could lead to synergistic or conflicting outcomes during acclimation to multiple and complex stresses, such as those arising from climate change.”

While the mitochondria are tiny sub-cellular bodies, their work is critical for understanding plant productivity. Dourmap and colleagues conclude that productivity can increase not just through understanding metabolic and biosynthetic processes, but also through understanding signalling. “[F]urther research should be carried out on the potential links between the mitochondrial signalling hubs, nuclear epigenetic regulation and mitochondrial epigenetics. Understanding these links should bring new insights into the involvement of mitochondria in the processes of stress memory and priming.”