Role of nitric oxide and hydrogen sulfide in plant aluminum tolerance.

As gasotransmitter, nitric oxide (NO) and hydrogen sulfide (H2 S) are involved in the regulation of plant tolerance to abiotic stresses. Aluminum (Al) toxicity triggers synthesis of NO and H2 S and seriously affects plant growth and productivity. Exogenous NO and H2 S alleviate Al toxicity in plants. However, the physiological and molecular mechanisms of NO and H2 S in alleviating Al toxicity are very scattered. In this review, the advances in the effects of Al on the content of endogenous NO and H2 S and the mechanisms of exogenous NO and H2 S in alleviating Al toxicity in plants are summarized and discussed. The signaling pathway for the roles of NO and H2 S in alleviating Al toxicity is also proposed.