Wheat Chloroplast Determination Of Protein-coding Genes Rna Editing Sites And Relation With Return White Phenomenon

RNA editing is a post-transcriptional process in which the nucleotide sequences of transcripts are changed by substitution, insertion or deletion. RNA editing was first found in1986, and this phenomenon is found in a variety of biological organisms, such as virus, bacteria, insect, plant and human. In high plants, it mainly occurs in transcripts of mitochondria and chloroplast.Wheat is an important food plant, and FA85is a wheat leaf stage albino mutation which was found in1985, Aibian1is the wild type. FA85is a good experimental plant for leaf albino mutation research. In this study, we are using prediction and experimental method to investigate the chloroplast RNA editing sites of FA85and Aibian1, results are as follow:1. We predicted28editing sites in17protein-coding genes from the chloroplast genome of Triticum aestivum. Using PCR, RT-PCR and sequencing technique, we identified RNA editing in14protein-coding genes from the chloroplast genome of Triticum aestivum. There are26editing sites in all are found in these genes,all of them are the conversion of C to U, Among them there are24RNA editing events are in the second position of codori, RNA editing obviously prefers to U_A context, increased the proportion of hydrophobic amino acids and the protein conservation.2. Compared with Aibian1, the chloroplast RNA editing sites of FA85are similar, but editing efficiency of5partial editing events is significantly different. They are rpoA C527, rpoB C467, rpoB C545, rpoB C560and rpoC2C4031. Editing efficiency of the5partial editing events between FA85and Aibian1are also different during different growing period.3. Bioinformatics research showed that all5editing sites are located in encoding PEP genes, rpoC2, rpoA and rpoB, and3of them predict alteration the secondary protein structure.4. Using semi quantitative RT-PCR, we further analyzed chloroplast genes transcriptional pattern which depend on PEP、 NEP and both PEP and NEP. Compared with wild type, most of the chloroplast genes mRNA transcription levels are lower in albino leaves.The results show that the decrease of editing efficiency and transcription level may be a reason to cause the leaf color changes.