镁（Mg）是植物生长必需的大量元素。作为一个被“遗忘”的元素，国内外关于水稻等作物镁元素吸收利用的遗传与育种研究基础薄弱。我们发现并克隆了一个定位在液泡膜上的水稻Mg2+逆向转运体OsMHX1，初步验证其具有Mg2+转运活性，并可能在维持水稻体内Mg2+平衡中起着重要作用。本项目利用酵母、非洲爪蟾卵母细胞、水稻T-DNA插入突变体、CRISPR-Cas9突变体和过量表达株系研究OsMHX1的Mg2+吸收转运活性；对转基因株系进行不同浓度Mg2+处理，利用SIET系统和25Mg-NMR技术关注亚细胞层面的元素变化，分析OsMHX1在维持水稻体内离子平衡中的作用；利用RNA-seq技术，分析OsMHX1参与调控Mg2+平衡的分子机制；利用已深度重测序的水稻种质资源挖掘OsMHX1的优异等位基因，比较全面地解析OsMHX1的生物学功能。本项目具有重要的生物学理论意义和育种应用价值。

Magnesium (Mg) is an essential element for plant growth. As a forgotten element, the genetic and breeding research on magnesium uptake and utilization in rice and other crops at home and abroad is weak. OsMHX1, a Mg2+/H+ exchanger, was found and cloned in rice. OsMHX1 is located on the vacuole membrane and has Mg2+ transport activity, which may play an important role in maintaining magnesium balance in rice. This project used yeast, Xenopus laevis oocyte, rice T-DNA insertion mutant, CRISPR-Cas9 mutant and overexpression lines to study the Mg2+ uptake and transport activity of OsMHX1. Transgenic lines were treated with different concentrations of Mg2+, and elemental changes at subcellular level were measured by SIET system and 25Mg-NMR technique to analyze the role of OsMHX1 in maintaining ion balance in rice. The molecular mechanism of OsMHX1 involved in regulating Mg2+ balance was analyzed by RNA-seq technology, and the excellent alleles of OsMHX1 were excavated from rice germplasm resources which had been deep re-sequenced, and the biological functions of OsMHX1 were comprehensively analyzed. This project has important biological theoretical significance and breeding application value.