Identification Of MiRNAs In Several Organisms

microRNAs(miRNAs)are a class of 19-24 nucleotides(nt)non-coding RNAs(ncRNAs)with stem-loop structures,which play important roles in posttranscriptional regulation.Therefore,identification of miRNAs of common traditional Chinese medicine and economic species enables us to have a better understanding of their pathedological mechanism.Also,it is conducive to distinguishing quality and cultivating them.Ophiocordyceps sinensis is a traditional Chinese medicine,an entomopathogenic fungus that infects larvae of Hepialidae ghost moths to form a parasitic complex,and it In china,O.sinensis has been used as health food or traditional Chinese medicine for over 2,000 years,which is effective to expand bronchial smooth muscles,inhibit tumor growth,reduce microorganism proliferation,modulate immune response and and decrease blood pressure.Since 1929 when Procambarus clarkia was introduced to China from Japan,it became one of the most important freshwater aquaculture species due to its adaptability and reproductive capacity.In this study9 we focus on Ophiocordyceps sinensi and Procambarus clarkia to identify and analyse their miRNAs.In the first part,we focused on Ophiocordyceps sinensi.Firstly,high-throughput sequencing and bioinformatics approaches were combined to identify conserved and novel microRNA-like RNAs(milRNAs)in O.sinensis.40 conserved milRNAs were identified,while 23 pre-miRNAs candidates encoding 31 novel milRNAs were predicted.Moreover,we predicted target genes of these conserved miRNAs and novel milRNAs in O.sinensis.Enrichment analysis of GO-represented biological process was used in order to have better understanding of functions of those target genes.The results showed that showed that target genes of both conserved and novel milRNAs are involved in development,metabolic and immune processes,indicating the potential roles of milRNAs of O.sinensis in pharmacological effects as health food and traditional Chinese medicine.Our study lay a foundation to the further analysis of milRNAs in O.sinensis.In the second part,we focused on Procambarus clarkia.Through analysis of high-throughput sequencing of heart ang gill sampling from crayfish that live in freshwater and salt water.We identified 101 conserved miRNAs and 2 novel pre-miRNAs and verified them by RT-qPCR.According to genome wide expression profile of salt-tolerance miRNAs,we chose three miRNAs to validate dynamic response to different salinity stages by RT-qPCR.It showed that the increasing salinity will lead to down-regulated expression of those miRNAs.The study of miRNAs in P.clarkia can help us better understanding the role of miRNAs in salt-tolerance in P.clarkia.