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植物NRT2基因家族(高亲和硝酸盐转运蛋白基因)在植物吸收和转运硝酸盐过程中发挥重要作用。本研究根据NRT2基因家族的保守序列设计兼并引物,扩增出一条821bp序列,以此序列为信息探针,通过电子克隆和RT-PCR的方法从烟草中克隆获得一个包含1593bp开放阅读框、编码530个氨基酸的c DNA序列,命名为Nt NRT2.4。生物信息学分析表明,该基因编码的蛋白质具有NRT家族的共有结构特征,与烟草已发现的三个本家族基因同源性达到77.54%,与拟南芥NRT2家族基因同源性达到81.63%,其启动子中包含多个与硝酸盐、光照及根系特异表达相关的元件;组织特异表达分析结果显示,烟草Nt NRT2.4基因的组织表达差异较大,在根部的表达量较高,在叶片和茎部的表达量低;不同氮素形态、光照和蔗糖处理下的基因表达分析结果表明,硝态氮、光照和蔗糖处理诱导Nt NRT2.4表达,而铵态氮抑制其表达。
The plant NRT2 gene family (high affinity nitrate transporter gene) plays an important role in plant uptake and transport of nitrate. According to the conserved sequences of NRT2 gene family, a pair of primers was designed to amplify a 821bp sequence. The sequence was used as a probe of information. A 1593bp open reading frame (ORF) was cloned from tobacco by electronic cloning and RT-PCR. The 530 amino acid c DNA sequence, designated Nt NRT2.4. Bioinformatics analysis showed that the protein encoded by this gene shared the common structural features of the NRT family, with 77.54% homology with the three published family genes of tobacco and 81.63% with the NRT2 family of Arabidopsis thaliana, Its promoter contains several elements related to nitrate, light and root specific expression. Tissue-specific expression analysis showed that the expression of tobacco Nt NRT2.4 gene was significantly different, with higher expression in the roots, The expression of Nt NRT2.4 in different nitrogen forms, light and sucrose treatments showed that nitrate nitrogen, light and sucrose induced the expression of Nt NRT2.4 and inhibited the expression of Nt NRT2.4.