Methyl jasmonate mitigates high selenium damage of rice via altering antioxidant capacity, selenium transportation...

Beneficial effects of methyl jasmonate (MeJA) on plants under different abiotic conditions have long been demonstrated. This study aimed to figure out how exogenous MeJA mitigated high-Se toxicity in rice from plant physiology and gene express perspective to provide the theory and technique for safe production of Se-rich rice. The results showed that low concentrations of MeJA at 0.1-1.0 μM inhibited high-Se induced nonreversible toxicity by enhancing antioxidant-system and reducing H₂O₂ and MDA content in rice seedlings. In comparison with control, addition of low concentrations of MeJA at 0.1-1.0 μM reduced the Se content in roots by 13.6-48.8% and in shoots by 52.6-59.9%. Besides, lower concentrations of MeJA decreased the Se(IV) transformation to SeCys and SeMet. The qRT-PCR analysis showed that application of low concentration of MeJA down-regulated the gene expression of OsNIP2;1, and OsPT2 in roots and OsNIP2;1, OsPT2, OsSBP1, and OsCS in shoots, which inhibited Se absorption. However, high concentrations of MeJA at 2.5-5.0 μM decreased antioxidant capacity and increased H₂O₂ and MDA content in rice seedlings. The results suggested that MeJA at 0.1-1.0 μM can be used to mitigate high-Se toxicity in rice production. This research augments the knowledge for future utilization of MeJA in down-regulating Se levels in crops.