Melatonin enhances the occurrence of autophagy induced by oxidative stress in Arabidopsis seedlings.

The beneficial effect that melatonin has against mitochondrial dysfunctioning seems to be linked to mitophagy. Roles for melatonin have been demonstrated in promoting health and preventing disease, as well as activating the process of autophagy in general. However, no reports have been made about how the application of melatonin regulates that process when plants are exposed to oxidative stress. We investigated the influence of different concentrations of melatonin (0.0, 0.5, 5.0, 10.0, or 50.0 μ m) on autophagy under methyl viologen ( MV)-induced oxidative stress. Arabidopsis seedlings that were pretreated with 5 or 10 μ m melatonin underwent relatively strong induction of autophagy, as evidenced by the number of monodansylcadaverine ( MDC)-stained autophagosomes in root samples. Pretreatment with 10 μ m melatonin also alleviated MV-induced photo-oxidation damage and significantly reduced the accumulation of oxidized proteins. Those responses might have been due to the strong upregulation of genes that involved in At ATG8- PE conjugation pathway, which enhanced the capacity for autophagy. Histochemical staining revealed that both [ABSTRACT FROM AUTHOR]