Jasmonic acid (JA) is thought to be involved in plant responses to cadmium (Cd) stress, but the underlying molecular mechanisms are poorly understood. Here, we show that Cd treatment rapidly induces the expression of genes promoting endogenous JA synthesis, and subsequently increases the JA concentration in Arabidopsis roots. Furthermore, exogenous methyl jasmonate (MeJA) alleviates Cd‐generated chlorosis of new leaves by decreasing the Cd concentration in root cell sap and shoot, and decreasing the expression of the AtIRT1, AtHMA2 and AtHMA4 genes promoting Cd uptake and long‐distance translocation, respectively. In contrast, mutation of a key JA synthesis gene, AtAOS, greatly enhances the expression of AtIRT1, AtHMA2 and AtHMA4, increases Cd concentration in both roots and shoots, and confers increased sensitivity to Cd. Exogenous MeJA recovers the enhanced Cd‐sensitivity of the ataos mutant, but not of atcoi1, a JA receptor mutant. In addition, exogenous MeJA reduces NO levels in Cd‐stressed Arabidopsis root tips. Taken together, our results suggest that Cd‐induced JA acts via the JA signaling pathway and its effects on NO levels to positively restrict Cd accumulation and alleviates Cd toxicity in Arabidopsis via suppression of the expression of genes promoting Cd uptake and long‐distance translocation.

中文翻译：

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茉莉酸通过抑制镉的吸收和转运来减轻拟南芥中的镉毒性。

茉莉酸（JA）被认为参与植物对镉（Cd）胁迫的反应，但其潜在的分子机制了解甚少。在这里，我们显示镉处理快速诱导促进内源JA合成的基因表达，并随后增加拟南芥根中JA的浓度。此外，外源茉莉酸甲酯（MeJA）通过降低根细胞汁液和芽中的Cd浓度，并分别降低促进Cd吸收和长距离易位的AtIRT1，AtHMA2和AtHMA4基因的表达，减轻了Cd引起的新叶萎黄病。。相反，关键的JA合成基因AtAOS的突变大大增强了AtIRT1，AtHMA2的表达。AtHMA4和AtHMA4可以增加根和芽中Cd的浓度，并提高对Cd的敏感性。外源MeJA可恢复ataos突变体增强的Cd敏感性，但不能恢复JA受体突变体atcoi1的Cd敏感性。此外，外源MeJA降低了镉胁迫的拟南芥根尖中的NO水平。综上所述，我们的结果表明，Cd诱导的JA通过JA信号传导途径及其对NO水平的影响，通过抑制促进Cd吸收和长距离易位的基因表达来积极限制Cd积累并减轻拟南芥中Cd的毒性。