矮珍珠硝酸盐转运蛋白基因GeNRT2.1的克隆和功能研究

硝酸盐转运蛋白（nitrate transporter，NRT）是植物识别、吸收和转运硝酸盐的关键蛋白，对促进作物根系发育、提高产量具有重要作用。通过筛选水生植物，利用NRT蛋白的保守区设计简并引物，并通过PCR和RACE技术，首次从矮珍珠（Glossostigma elatinoides）中克隆得到GeNRT2.1基因。进化分析结果表明，GeNRT2.1与烟草NRT2.1在进化关系上距离最近。qRT-PCR结果表明，GeNRT2.1在矮珍珠根中表达量最高，其次是叶和茎，此外，低浓度硝酸盐（0.5 mmol·L^-1）处理后，GeNRT2.1在根、叶、茎中的表达量分别是高浓度硝酸（2 mmol·L^-1）处理后的1.89、1.93和2.07倍。功能互补实验发现，GeNRT2.1能使缺陷型酵母Δynr恢复生长，具有硝酸盐转运蛋白的功能。通过丰富NRT基因资源，以期为培育氮肥高效利用转基因作物，发展绿色农业，保证我国的粮食安全和环境安全提供理论依据。

Cloning and Functional Studies of Nitrate Transporter Gene GeNRT2.1 in Glossostigma elatinoides

Nitrate transporter （NRT） is a key protein for plants to recognize， absorb and transport nitrate， which plays an important role in promoting crop root development and crop yield improving. In this study， through the screening of aquatic plants， we used Glossostigma elatinoides as materials， designed degenerate primers based on the conserved regions of NRT proteins in different species， used PCR and RACE technology to clone GeNRT2.1 gene for the first time. Evolutionary analysis results showed that GeNRT2.1 was most closely related to Nicotiana tabacumNRT2.1 in evolutionary relationship. qRT-PCR results showed that the expression of GeNRT2.1 in roots was the highest， followed by leaves and stems. In addition， the expression of GeNRT2.1 in roots， leaves， and stems of low concentration nitrate （0.5 mmol·L^-1） were 1.89， 1.93 and 2.07 times than that of high concentration nitrate （2 mmol·L^-1）. Functional complementation experiments results showed that GeNRT2.1 could restore the growth of defective yeast Δynr， and has the function of nitrate transporter. By enriching NRT genetic resources， this study hopes to provide a theoretical basis for cultivating genetically modified crops with high-efficiency utilization of nitrogen fertilizer， developing green agriculture， and ensuring food security and environmental safety in our country.