The role of autophagy in alleviating damage of aluminum stress in Arabidopsis thaliana

Abstract

Aluminum is one of the toxic elements in acid soil which can restrain plant growth. Autophagy, a dynamic process that involves the recycling of the degradation of intracellular materials, can be induced by multiple abiotic stresses in Arabidopsis. However, the relationship between aluminum and autophagy in plant is unclear while it has been reported that aluminum can increase astrocyte autophagy levels in animals. The role of autophagy in aluminum stress response in Arabidopsis was therefore studied. Our results showed that aluminum can increase expression of autophagy-related genes’ level, moreover, autophagy defective mutants were more sensitive to aluminum conditions and showed more serious damages than wild-type plants, including higher oxidative damages and more reactive oxygen species (ROS) accumulation. Then, inductions of defense-associated genes in autophagy defective mutants were less than that observed in the wild-type plants after aluminum treatment, whereas the former had higher antioxidant enzymes activity. Furthermore, mutants were more compromised in PSII photochemistry and their detached leaves had less ability to stay green under aluminum treatment. These results indicate that aluminum can induce autophagy and the latter is necessary for defense responses to aluminum toxicity in Arabidopsis thaliana, and it may relieve this damage by eliminating the overproduction of ROS.