Cadmium (Cd) and excess copper (Cu) are toxic to plants, causing a wide range of deleterious effects including the formation of reactive oxygen species. Metallothioneins (MTs) may protect plant cells from heavy metal toxicity by chelating heavy metals via cysteine thiol groups. They may also function as antioxidants. The study investigated the relationship of H2O2 production and ricMT expression in rice radicles and rice suspension cells under Cu or Cd stress. The results showed that H2O2 production in the rice radicles increased before Cu-induced ricMT expression, and after Cd-induced ricMT expression. Rice suspension cells of sense- and antisense-ricMT transgenic lines were obtained by an Agrobacterium-mediated transformation. Overexpression of ricMT significantly decreased the death rate of rice cells, which was accompanied by blocked H2O2 accumulation in rice suspension cells subject to Cu and Cd stress. Our findings confirm that H2O2 is involved in the MT-mediated tolerance of Cu and Cd toxicity in rice.

中文翻译：

---

H2O2参与金属硫蛋白介导的水稻对铜和镉毒性的耐受性

镉（Cd）和过量的铜（Cu）对植物有毒，引起广泛的有害影响，包括形成活性氧。金属硫蛋白（MTs）可以通过半胱氨酸巯基螯合重金属来保护植物细胞免受重金属的毒性。它们也可以用作抗氧化剂。该研究探讨了Cu或Cd胁迫下水稻胚根和水稻悬浮细胞中H2O2产生与ricMT表达的关系。结果表明，在Cu诱导的ricMT表达之前和Cd诱导的ricMT表达之后，水稻胚根中H2O2的产生增加。通过农杆菌介导的转化获得有义和反义ricMT转基因品系的水稻悬浮细胞。ricMT的过表达显着降低了水稻细胞的死亡率，伴随着过剩的H2O2在受Cu和Cd胁迫的水稻悬浮细胞中积累。我们的发现证实，H2O2参与了MT介导的水稻对Cu和Cd毒性的耐受性。