二色补血草OEE2基因的克隆和表达

Cloning and Expression Analysis of An Oxygen-evolving Enhancer Protein Ⅱ Gene(OEE2) from Limonium bicolor(Bunge) Kuntze

从二色补血草中分离出一条含有完整开放读码框(ORF)序列的OEE2基因。该基因全长994bp,其中5'非翻译区27bp,3'非翻译区160bp,ORF全长807bp,共编码264个氨基酸,编码蛋白的分子量为28.2kDa,理论上的等电点为7.66。BlastP分析表明,二色补血草OEE2与马铃薯OEE2序列同源性最高,与喇叭水仙OEE2序列同源性最低,从9个物种的氨基酸多序列比对中可以看出,OEE2的氨基酸序列保守性较高。实时定量RT-PCR方法检测该基因对低温、NaCl和聚乙二醇(PEG)胁迫的基因表达模式的结果表明,PEG和低温能诱导OEE2基因在二色补血草叶中表达,这两种处理的OEE2基因表达量于胁迫48h后都达到高峰,而在NaCl胁迫下OEE2在二色补血草根和叶中表达都受抑制。

The sequence of oxygen-evolving enhancer protein II （OEE2）, which contained a complete open reading frame （ORF）, was cloned from a cDNA library of Limonium bicolor. The sequence was 994 bp in length, including a 27 bp sequence of 5＇ untranslated region and a 160 bp sequence of 3＇ untranslated region. It had an ORF of 807 bp in length, which encoded a deduced amino acids of 264 residues. The molecular weight of deduced protein was 28.2 kDa with a theoretical pI of 7.66. Multiple sequence alignments of OEE2 proteins from 9 plant species revealed that the OEE2 proteins shared high identities in amino acid sequence. The BlastP analysis revealed that amino acid sequence of OEE2 protein from L. bicolor shared the highest amino acid sequence similarity with that from Solanum tuberosum and the lowest similarity with that from Narcissus pseudonarcissus among the 9 OEE2 proteins. We examined the expression pattern of the OEE2 gene in leaves and roots of L. bicolor in response to NaCl, low temperature and PEG stresses at different time points by using real time RT-PCR. The results showed that OEE2 could be induced by low temperature and PEG treatment in leaves, its expression reached maximum level after treatment for 48 h by both low temperature and PEG. However, the expression of OEE2 was inhibited by NaCl treatment in both leaves and roots of L. bicolor.