The outcomes of the functional interplay of nitric oxide and hydrogen sulfide in metal stress tolerance in plants

Phytotoxicity of metals constraints plants health, metabolism and productivity. The sustainable approaches for minimizing major metals-accrued phytotoxicity have been least explored. The gasotransmitters signaling molecules such as nitric oxide (NO) and hydrogen sulfide (H2S) play a significant role in the mitigation of major consequences of metals stress. Versatile gaseous signaling molecules, NO and H2S are involved in the regulation of various physiological processes in plants and their tolerance to abiotic stresses. However, literature available on NO or H2S stand alone, and the major insights into the roles of NO and/or H2S in plant tolerance, particularly to metals, remained unclear. Given above, this paper aimed to (a) briefly overview metals and highlight their major phytotoxicity; (b) appraises literature reporting potential mechanisms underlying the roles of NO and H2S in plant-metal tolerance; (c) crosstalk on NO and H2S in relation to plant metal tolerance. Additionally, major aspects so far unexplored in the current context have also been mentioned.