Key Laboratory of Marine, Food Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences, China Jiliang University, Hangzhou 310018, People's Republic of China.
Key Laboratory of Plant Nutrition and Fertilizer, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Science, Beijing 100081, China.
Plant Physiol. 2018 Aug;177(4):1691-1703. doi: 10.1104/pp.18.00485. Epub 2018 Jun 20.
MicroRNAs (miRNAs) are 20- to 24-nucleotide small noncoding RNAs that regulate gene expression in eukaryotic organisms. Several plant miRNAs, such as miR166, have vital roles in plant growth, development and responses to environmental stresses. One such environmental stress encountered by crop plants is exposure to cadmium (Cd), an element highly toxic to most organisms, including humans and plants. In this study, we analyzed the role of miR166 in Cd accumulation and tolerance in rice (). The expression levels of miR166 in both root and leaf tissues were significantly higher in the reproductive stage than in the seedling stage in rice. The expression of miR166 in the roots of rice seedlings was reduced after Cd treatment. Overexpression of miR166 in rice improved Cd tolerance, a result associated with the reduction of Cd-induced oxidative stress in transgenic rice plants. Furthermore, overexpression of miR166 reduced both Cd translocation from roots to shoots and Cd accumulation in the grains. miR166 targets genes encoding the class-III homeodomain-Leu zipper (HD-Zip) family proteins in plants. In rice, () gene (Os03g43930), which encodes an HD-Zip protein, was up-regulated by Cd treatment but down-regulated by overexpression of miR166 in transgenic rice plants. Overexpression of increased Cd sensitivity and Cd accumulation in the leaves and grains of transgenic rice plants. By contrast, silencing by RNA interference enhanced Cd tolerance in transgenic rice plants. These results indicate a critical role for miR166 in Cd accumulation and tolerance through regulation of its target gene, , in rice.
MicroRNAs (miRNAs) 是 20-24 个核苷酸的小非编码 RNA，它们在真核生物中调节基因表达。几种植物 miRNAs，如 miR166，在植物生长、发育和对环境胁迫的响应中起着重要作用。作物植物遇到的一种环境胁迫是暴露于镉 (Cd)，Cd 是一种对包括人类和植物在内的大多数生物都高度有毒的元素。在这项研究中，我们分析了 miR166 在水稻中的 Cd 积累和耐受中的作用。miR166 在根和叶组织中的表达水平在水稻的生殖阶段明显高于幼苗阶段。水稻幼苗根系中 miR166 的表达在 Cd 处理后降低。miR166 的过表达提高了 Cd 耐受性，这与转基因水稻植株中 Cd 诱导的氧化应激减少有关。此外，miR166 的过表达减少了 Cd 从根部向地上部的转运和 Cd 在谷物中的积累。miR166 靶向植物中编码 III 类同源域-亮氨酸拉链 (HD-Zip) 家族蛋白的基因。在水稻中，()基因（Os03g43930），它编码一个 HD-Zip 蛋白，被 Cd 处理上调，但在转基因水稻植株中被 miR166 的过表达下调。的过表达增加了转基因水稻叶片和谷粒中的 Cd 敏感性和 Cd 积累。相比之下，通过 RNA 干扰沉默增强了转基因水稻植株对 Cd 的耐受性。这些结果表明，miR166 通过调节其靶基因（）在水稻中的 Cd 积累和耐受中起着关键作用。
