LAUSR

Soil contamination with trace metals and metalloids can cause toxicity to plants and threaten food safety and human health. Plants have evolved sophisticated mechanisms to cope with excess trace metals and metalloids in soils, including chelation and vacuolar sequestration. Sulfur-containing compounds, such as glutathione and phytochelatins, play a crucial role in detoxification of toxic trace metals and metalloids in plants. Sulfur uptake and assimilation are regulated in response to the stress of toxic trace metals and metalloids. This review focuses on the multi-level connections between sulfur homeostasis in plants and responses to the stresses of trace metals and metalloids, especially arsenic and cadmium. We review recent progress on understanding the regulations of biosynthesis of glutathione and phytochelatins and the sensing mechanism of sulfur homeostasis for tolerance of trace metals and metalloids in plants. We also discuss the role of glutathione and phytochelatins in controlling the accumulation and distribution of arsenic and cadmium in plants, and the strategies of manipulating sulfur metabolism to limit arsenic and cadmium accumulation in food crops.