小麦Na+/H+反转运蛋白基因的克隆和特性

摘要

以水稻(Oryza sativa L.) Na+/H+反转运蛋白cDNA片段为探针,从小麦盐胁迫cDNA文库中筛选和克隆了2个小麦Na+/H+反转运蛋白基因,分别命名为TaNHX1 和 TaNHX2.序列分析表明TaNHX1为2 029 bp,包含一个完整的1 638 bp的ORF,编码546个氨基酸,其中含有DIFFIYLLPPI跨膜区.TaNHX2为1 693 bp,包含部分ORF及808 bp的3′-UTR.这2个基因与已知的水稻、拟南芥(Arabidopsis thialiana)和滨藜(Atriplex gmelini)中的同类基因NHX的相似性约为70%.RT-PCR分析表明小麦苗经400 mmol/L NaCl处理1 h后,TaNHX1的转录水平有所提高.%The Na+/H+ antiport genes named TaNHX1 and TaNHX2 were cloned by screening a salt-stressed wheat cDNA library using rice Na+/H+ antiport cDNA fragment as the probe. Sequencing analysis showed that TaNHX1 was 2 029 bp in length and contained a complete ORF of 1 638 bp. The TaNHX1 encodes a polypeptide of 546 amino acids with a transmembrane domain DIFFIYLLPPI. TaNHX2 was 1 693 bp in length consisting of a partial ORF followed by a 3′-UTR of 808 bp. The amino acid sequence of these two genes were about 70% identical to the known NHX genes from rice, Arabidopsis and Atriplex. A RT-PCR assay showed that the level of TaNHX1 transcripts was increased and reached a steady higher level in the seedlings after 3 h treatment with 400 mmol/L NaCl.