MicroRNA166 Modulates Cadmium Tolerance and Accumulation in Rice
MicroRNA166 Modulates Cadmium Tolerance and Accumulation in Rice
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MicroRNA166 调节水稻的镉耐受性和积累
DOI：
10.1104/pp.18.00485
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发表时间：
2018-08-01
期刊：
影响因子：
7.4
通讯作者：
Zhu, Cheng
中科院分区：
文献类型：
--
作者：
Ding, Yanfei;Gong, Shaohua;Zhu, Cheng
microRNAs（miRNAs）是一种由20 ~ 24个核苷酸组成的小分子非编码RNA，在真核生物中调节基因表达。miR 166等几种植物miRNAs在植物的生长发育和对环境胁迫的响应中具有重要作用。作物所遇到的一种这样的环境压力是暴露于镉（Cd），镉是对包括人类和植物在内的大多数生物体具有高度毒性的元素。本研究分析了miR 166在水稻镉积累和耐性中的作用。miR 166在水稻根和叶组织中的表达量在生殖生长期显著高于苗期。镉处理后，水稻幼苗根系中miR 166的表达量降低。miR 166在水稻中的过表达提高了镉的耐受性，这一结果与转基因水稻中镉诱导的氧化胁迫的减少有关。此外，miR 166的过表达降低了Cd从根向地上部的转运和Cd在籽粒中的积累。miR 166靶向植物中编码III类同源结构域-Leu拉链（HD-Zip）家族蛋白的基因。在水稻中，编码HD-Zip蛋白的同源域蛋白4（OsHB 4）基因（Os 03 g43930）在镉处理下表达上调，而在miR 166过表达下表达下调。过量表达OsHB 4可提高转基因水稻对Cd的敏感性，增加叶片和籽粒中Cd的积累。相比之下，通过RNA干扰沉默OsHB 4增强了转基因水稻对镉的耐受性。这些结果表明miR 166通过调控其靶基因OsHB 4在水稻镉积累和耐性中起关键作用。
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 (Oryza sativa). 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, HOMEODOMAIN CONTAINING PROTEIN4 (OsHB4) 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 OsHB4 increased Cd sensitivity and Cd accumulation in the leaves and grains of transgenic rice plants. By contrast, silencing OsHB4 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, OsHB4, in rice.