超氧化物歧化酶是一种广泛存在于真核生物中的金属酶类, 在植物的抗逆性中起到重要的作用。文章采用RACE方法, 从东方山羊豆中克隆了Cu/ZnSOD基因, 并对其进行了初步分析。该基因cDNA序列全长935 bp, 开放阅读框600 bp, 编码199个氨基酸, 蛋白质分子量为20.35 kDa。通过实时荧光定量PCR结果分析, 该基因在东方山羊豆叶中表达量最多, 茎中次之, 根中最少。在NaCl和PEG诱导下, Cu/ZnSOD基因表达量先上调后下降。NaCl诱导24 h后, 该基因的表达量显著低于对照。ABA胁迫抑制了该基因的表达。亚细胞定位结果表明, Cu/ZnSOD蛋白定位于叶绿体中。实验结果证明, Cu/ZnSOD基因主要在东方山羊豆的绿色组织中表达, 在抵抗渗透性胁迫方面起到一定作用。
SOD is an important enzyme which exists in eukaryote extensively and plays an essential role in stress-tolerance of higher plants. A cDNA of Cu/ZnSOD gene was cloned from Galega orientalis L. using rapid amplification of cDNA ends (RACE) method. The full-length of cDNA sequence is 935 bp, included a 600 bp open reading frame which encoded a 199-amino-acid polypeptide. The molecular weight of this protein was 20.35 kDa. The results of Real-Time PCR indicated that the expression level of Cu/ZnSOD gene was the highest in leaves, moderate in stems, and the least in roots. The expression of Cu/ZnSOD gene under stress of NaCl and PEG was up-regulated firstly and then declined. The expression level was significantly lower than the control after 24 h treated with NaCl. Abscisic acid downregulated the expression of Cu/ZnSOD gene. The result of subcellular localization indicated that Cu/ZnSOD was located in chloroplast. Gene Cu/ZnSOD mainly expressed in the green organs of G. orientalis and played a certain role in resisting osmotic stress.
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