青稞叶绿体基因RNA编辑位点的预测、鉴定与比较分析

Prediction,Identification and Characterization of the Chloroplast RNA Editing Sites of Hulless Barley

为了阐明青稞叶绿体基因组RNA编辑位点的组成与特性,首先利用生物信息工具对青稞叶绿体基因的RNA编辑位点进行了预测,结果发现了35个分布于15个基因的编辑位点,所有编辑均为C到U的转换,其中基因ndhB包含的编辑位点数量最多,达9个,这与其他麦类作物相似;进一步利用RT-PCR结合克隆测序,对预测的35个位点进行了实验验证,发现18个编辑位点被证实发生了C到U的编辑;对编辑前后编码蛋白质的结构进行了比较分析,发现RNA编辑引起了编码蛋白的结构变化,暗示RNA编辑可以造成编码蛋白功能的改变。最后,将青稞叶绿体基因RNA编辑位点与栽培大麦、野生大麦的叶绿体RNA编辑位点进行了比较,发现青稞与栽培大麦的RNA编辑组成完全一样,而野生大麦缺失了ndhA-563位点,初步印证了大麦的起源进化关系。

As an important way to regulate gene expression at post-transcriptional level in eukaryotes,RNA editing events are widely found in plant chloroplasts,which play an important role in regulating plant growth,morphogenesis and stress response.At present,the study on RNA editing in chloroplast genome of hulless barley has not been reported.In order to elucidate the composition and characteristics of RNA editing in hulless barley chloroplast genome,the RNA editing sites were predicted and analyzed using bioinformatics tools combined with RT-PCR.A total of 35editing sites were found,distributed in 15genes.In addition,all editing sites are C-U transformations,and ndhB possesses the most abundant editing sites,which is consistent with that in other crops.Furthermore,the predicted 35sites were validated by RT-PCR combined with cloning and sequencing,and 18editing sites were confirmed to have C-U editing.At the same time,the structure of the protein before and after editing was compared.It was found that RNA editing causes the structural changes of proteins,suggesting that RNA editing can affect the corresponding biological functions.Finally,the chloroplast RNA editing sites of hullessbarley were compared with those of cultivated barley and wild barley.Results showed that the editing compositions of hulless barley and cultivated barley are exactly identical,while wild barley lacks of ndhA-563site,which confirmed the relationship between barley origin and phylogenetic relationship.This study provides the necessary information for further study on biological functions and effects of chloroplast RNA editing in hullessbarley,and also provides the useful knowledge for revealing the origin and evolution of barley from the perspective of chloroplast RNA editing.