New insights into plant autophagy: molecular mechanisms and roles in development and stress responses.

Autophagy is an evolutionarily conserved eukaryotic intracellular degradation process. Although the molecular mechanisms of plant autophagy share similarities with those in yeast and mammals, certain unique mechanisms have been identified. Recent studies have highlighted the importance of autophagy during vegetative growth stages as well as in plant-specific developmental processes, such as seed development, germination, flowering, and somatic reprogramming.

A proposed role for endomembrane trafficking processes in regulating tonoplast content and vacuole dynamics under ammonium stress conditions in Arabidopsis root cells.

Ammonium (NH) stress has multiple effects on plant physiology, therefore, plant responses are complex, and multiple mechanisms are involved in NH sensitivity and tolerance in plants. Root growth inhibition is an important quantitative readout of the effects of NH stress on plant physiology, and cell elongation appear as the principal growth inhibition target. We recently proposed autophagy as a relevant physiological mechanisms underlying NH sensitivity response in Arabidopsis.

Ammonium stress increases microautophagic activity while impairing macroautophagic flux in Arabidopsis roots.

Plant responses to NH stress are complex, and multiple mechanisms underlying NH sensitivity and tolerance in plants may be involved. Here, we demonstrate that macro- and microautophagic activities are oppositely affected in plants grown under NH toxicity conditions. When grown under NH stress conditions, macroautophagic activity was impaired in roots.