Computational identification and comparative analysis of miRNAs in wheat group 7 chromosomes

Abstract

MicroRNAs (miRNAs) are a class of important biological elements that regulates gene expression by translational repression or transcript degradation both in plants and animals. The origin, distribution and evolution of the miRNA genes have been systematically studied in many model plants, but they are not well understood in wheat. In this study, we have systematically identified the miRNA precursors and mature miRNAs in wheat group 7 chromosomes by computational analysis in the isolated chromosome sequences. A total of 716 precursors belonging to 43 miRNA families were identified, of which 12 miRNAs families (27.91 %) were not reported in wheat. Further analysis found that there were less mature miRNAs but more miRNA precursors distributing on 7D compared to 7A and 7B, suggesting that wheat group 7 homoeologous chromosome eliminated some miRNA precursors with the potential to yield the same miRNA and formed a more precise regulatory network via the two hybridization events. The target genes of all the newly identified miRNAs were also predicted. The results of this study are beneficial to improve our understanding of the distribution of wheat miRNAs and its evolutionary role in polyploidisation.