菘蓝铁型超氧化物歧化酶基因IiFeSOD的克隆与胁迫表达分析

Clone and stress expression analysis of iron superoxide dismutase from Isatis indigotica

关键词:  菘蓝  SOD  盐胁迫  表达分析  酶活性分析

Key words:  Isatis indigotica  iron superoxide dismutase  salt stress  expression analysis  activity analysis

摘要:

超氧化物歧化酶(SOD)是生物体内超氧阴离子自由基的清除剂,可有效地防止它们对生物体的损害。从菘蓝中经RT-PCR方法扩增得到SOD基因,命名为IiFeSOD,其全长882 bp,包含一个834 bp的ORF,编码277个氨基酸,分析其编码的蛋白质序列显示其属于铁型超氧化物歧化酶,具有线粒体导肽,定位于线粒体中。实时荧光定量PCR技术分析结果表明,IiFeSOD在菘蓝各个组织中均有表达,但表达量高低不同,在叶中表达最高、茎次之、根中最低; 该基因受盐胁迫的诱导,随着盐胁迫强度的加强基因表达量迅速升高而后下降。同时SOD酶活性在盐胁迫处理下表现出类似的变化规律。说明SOD的大量积累与植物的耐逆性密切相关。

Abstract:

Superoxide dismutase is a scavenger of superoxide anion free radical in vivo. They can effectively prevent reactive oxygen species damage to organism. An iron superoxide dismutase gene was isolated from Isatis indigotica, and was named as IiFeSOD. The full-length cDNA of IiFeSOD contained a 834 bp open reading frame(ORF)and encoded 277 amino acids, which might locate in mitchondria. Real-time PCR analysis showed that IiFeSOD had the highest expression in leaves,then in stems,and the least in roots. The expression level of IiFeSOD could be induced by NaCl. Levels of IiFeSOD transcripts could increase at three days after salt stress. However,the expression of IiFeSOD first increased and then decreased after salt stress at 100 mmol/L. Activity of SOD was also induced by NaCl and showed the analogous change rule with gene expression. Studies showed that massive accumulation of SOD was closely related with the stress tolerance of plants.