碱茅(Puccinellia tenuifolra)Put-Cu／Zn-SOD基因的克隆及在酵母中的表达

Cloning of a Cu/Zn Superoxide Dismutase Gene from Puccinellia tenuifolra and its Expression in Yeast

从碱茅根cDNA文库分离得到Put-Cu/Zn-SOD全长cDNA,其序列全长为2700bp,该基因的开放读码框为长615bp,所编码的蛋白由204个氨基酸组成,其预测分子量约为20.6kD、理论等电点约为5.63。Put-Cu/Zn-SOD氨基酸序列与水稻Cu/Zn-SOD序列有较高的同源性为87%。将Put-Cu/Zn-SOD基因构建到酵母表达载体pYES2,并转化至酵母(INVSc1)。对pYES2-Put-Cu/Zn-SOD转化酵母进行盐碱、氧化胁迫实验。结果表明:重组酵母的抗盐碱、氧化能力明显高于对照(pYES2转化酵母),结果显示了碱茅的Cu/Zn-SOD基因在酵母表达中,具有提高酵母抗盐碱和耐氧化能力。

The full sequence of cDNA sequence of Cu/Zn-SOD gene was cloned from Puccinellia tenuifolra. The Cu/Zn-SOD gene is 2 700 bp in length. It has an open reading frame （ORF） of 615 bp, encoding a protein of 204 amino acid residues, with protein molecular weight of 20.6 kD and isoelectric point of 5.63. The similarities between the Cu/Zn-SOD from Puccinellia tenuifolra shared the highest similarities （87%） in amino acid sequence with that from maize. The Cu/Zn-SOD gene was transformed into yeast cells （saccharomyces cerevisiae） for expression. The recombinant yeast INVSc 1 （harboring ppYES2-SOD） and control INVSc 1 （harboring empty pYES2） were treated with salt and oxidation stresses. The results revealed that the recombinant yeast cells have a higher stress resistance than control cells. It also proved that the Cu/Zn-SOD from Puccinellia tenuifolra has the ability of salt and oxidation resistance.