Cadmium (Cd) is an element with high toxicity to living organisms, and its accumulation in rice grains poses a threat to human health. In this study, we report a novel nickel-transport family protein, OsNTP1, that is involved in Cd transport from root to shoot. Heterologous expression of OsNTP1 in yeast enhanced Ni and Cd tolerance. In rice, the transporter OsNTP1 is localized at the chloroplast and the expression of OsNTP1 was rapidly induced by Cd treatment. Under Cd²⁺ treatment, the Cd content in the shoots of OsNTP1-RNAi lines was significantly increased. Notably, knockdown of OsNTP1 significantly reduces Cd accumulation in the grains, highlighting its critical role in minimizing Cd contamination in edible parts of the plant. In addition, knockout or knockdown OsNTP1 also increased sensitivity to sucrose. Sucrose treatment led to more starch particles at the OsNTP1-RNAi shoot base, and exogenous sucrose can alleviate the inhibitory effects of Cd stress on sugar metabolism and starch synthesis in OsNTP1-RNAi lines. The present study provides a new genetic resource for breeding low-Cd grains and exploring the response mechanisms of sugar metabolism to Cd stress.

中文翻译：

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叶绿体定位转运蛋白 OsNTP1 介导水稻中镉从根到芽的运输和糖代谢


镉 （Cd） 是一种对生物体具有高毒性的元素，它在米粒中的积累对人类健康构成威胁。在这项研究中，我们报道了一种新的镍转运家族蛋白 OsNTP1，它参与 Cd 从根到芽的转运。OsNTP1 在酵母中的异源表达增强了 Ni 和 Cd 耐受性。在水稻中，转运蛋白 OsNTP1 位于叶绿体上，Cd 处理迅速诱导 OsNTP1 的表达。在 Cd²⁺ 处理下，OsNTP1-RNAi 系枝条中的 Cd 含量显著增加。值得注意的是，OsNTP1 的敲除显着减少了谷物中 Cd 的积累，突出了其在最大限度地减少植物可食用部分 Cd 污染方面的关键作用。此外，敲除或敲低 OsNTP1 也增加了对蔗糖的敏感性。蔗糖处理导致 OsNTP1-RNAi 芽基部淀粉颗粒增加，外源蔗糖可以减轻 Cd 胁迫对 OsNTP1-RNAi 系糖代谢和淀粉合成的抑制作用。本研究为培育低 Cd 籽粒和探索糖代谢对 Cd 胁迫的响应机制提供了新的遗传资源。