盐桦BhNHX的克隆及其与CaM在胁迫下的协同表达(英文)

Cloning of BhNHX Gene from Betula halophila and Its Co-expressional Regulation with CaM Gene under Different Stresses

以盐桦组培苗为材料,通过RACE技术克隆了液泡膜Na+/H+反向运输体基因BhNHX,采用DNAman软件和BLASTN对cDNA序列进行分析并与其他植物的NHX基因进行同源性比较,最后对BhNHX和钙调蛋白基因(CaM)在各种胁迫条件下的协同表达进行半定量的RT-PCR分析.结果显示:(1)获得了BhNHX的全长cDNA序列,包含1 623 bp的开放阅读框架,编码一个540个氨基酸的多肽,有11个推测跨膜区,与已报道的液泡膜Na+/H+反向运输载体蛋白跨膜区数目一致;(2)BhNHX的核酸序列与其他植物NHX具有较高同源性,与葡萄NHX序列一致性达到76%;(3)BhNHX和钙调蛋白基因CaM可同时被盐、低温、干旱所诱导;但ABA只能较明显诱导BhNHX的表达,而对CaM的诱导表达不明显.研究表明,在盐桦受到盐、低温及干旱胁迫时BhNHX和CaM可能协同表达,而在ABA诱导时两者可能具有不同的表达调控模式.

A vacuolar Na^＋/H^＋ antiporter cDNA fragment of BhNHX was cloned from the tissue culture regeneration plantlets of Betula halophila,a special halophytic arbor distributed in Xinjiang,and the ORF sequence analysis and homology comparison of the cDNA were performed by using DNAman software and BLASTN program,then the co-expression of BhNHX and calmodulin gene（CaM） under various stresses was detected by semi-quantitative RT-PCR.The results showed：（1） The acquired full length of the BhNHX cDNA included an ORF of 1 623 bp with a 5′-untranslated region of 142 bp and a 3′-untranslated region of 337 bp,encoded a peptide of 540 deduced amino acids,and had 11 putative transmembrane regions which were identical with other reported vacuole-type Na^＋/H^＋ antiporters,（2）The nucleotide sequence of BhNHX had relatively high homology with that of other plants,and shared 76% identity with Vitis vinifera,（3）The semi-quantitati ve RT-PCR results showed that expressions of BhNHX and CaM could be both induced by salt,cold and drought stresses,（4）ABA can induce the expression of BhNHX but almost have no effect on CaM expression.These results suggested that BhNHX and CaM might express synergistically in B.halophila under salt,cold and drought stresses,however,they might be regulated through different pathways when induced by ABA.