A schematic model representing the involvement of miPEP408 in regulating miR408 transcription and sulfur metabolism under LS and as(III) stress. This model represents the key role of miPEP408 in regulating the sulfur reduction pathway via pri-miR408 transcription. The mature miR408 in cytoplasm targets GSTU25 transcript and may modulate sulfur metabolism. Genes involved in sulfur metabolism with modulated expression are marked as red. (?) symbol represents that the direct role of GSTU25 in sulfur assimilation pathway needed to be explored. LS, low sulfur; As(III), arsenite; ROS Reactive Oxygen Species.