甘薯NRT基因家族成员鉴定及其在不同氮素条件下的表达模式分析

Identification of Sweetpotato NRT Gene Family Members and Expression Patterns Analysis under Different Nitrogen Conditions

硝酸盐转运蛋白NRTs参与植物对硝态氮的吸收、转运,促进植物生长。为探究甘薯响应硝态氮供应的机制及其硝酸盐转运蛋白IbNRT基因家族的功能,本研究测定菜用甘薯在不同NO_(3)^(-)-N条件下硝酸还原酶、谷氨酰胺合成酶活性的动态变化,并利用生物信息学方法鉴定出76个IbNRT家族成员,分析其基因结构、进化关系、保守基序、顺式作用元件以及低氮胁迫下的基因表达模式。结果显示:低氮胁迫降低菜用甘薯酶活性,各处理在胁迫2 d后达显著差异。甘薯IbNRT家族分为IbNRT1、IbNRT2、IbNRT3三个亚族,定位在细胞膜上,分布在13条染色体上,均含特定的保守结构域,启动子区含多种类型的顺式作用元件。IbNRT家族亚家族内蛋白序列保守性较强,但亚家族间差异显著。RT-qPCR结果显示,IbNRT基因表达受营养液NO_(3)^(-)-N浓度的影响,表明IbNRT基因家族参与甘薯对氮素的响应过程,该研究结果可为进一步甘薯硝酸盐转运蛋白IbNRT家族基因的克隆及功能研究提供一定的参考。

Nitrate transporters NRTs participate in the absorption and transport of nitrate nitrogen by plants,and promote plant growth.In order to explore the mechanism of sweetpotato responding to nitrate nitrogen supply and the function of the nitrate transporter IbNRT gene family,this study determined the dynamic changes of nitrate reductase and glutamine synthetase activities of vegetable sweetpotato under different NO_(3)^(-)-N conditions.Using bioinformatics methods,76 IbNRT family members were identified,and their gene structure,evolutionary relationship,conservative motifs,cis-acting elements,and gene expression patterns under low nitrogen stress were analyzed.The results showed that the low nitrogen stress reduced the enzyme activity of vegetable sweetpotato,and each treatment reached a significant difference after 2 days of low nitrogen stress.The sweetpotato IbNRT family is divided into three sub-families:IbNRT1,IbNRT2,and IbNRT3.They are located on the cell membrane and distributed on 13 chromosomes.They all contain specific conserved domains.The promoter region contains many types of cis-acting elements.IbNRT family subfamily has strong protein sequence conservation,but there are significant differences between subfamilies.The results of RT-qPCR showed that the expression of IbNRT gene was affected by the concentration of NO_(3)^(-)-N in the nutrient solution,indicating that the IbNRT gene family is involved in the response process of sweetpotato to nitrogen.The results of this study can provide a certain reference for further study on the cloning and function of the IbNRT family genes of the sweetpotato nitrate transporter.