Construction Of A Medicinal Plant MicroRNA Database

MicroRNAs(miRNAs)are single-stranded endogenous non-coding RNAs of approximately 20 to 22 nt in length.MiRNAs have been recognized as a critical modulator of performing gene regulation in eukaryotes.It is found that miRNA is an effective regulatory factor for plant development,such as plant growth,flowering time and fertility,and also plays an essential role in plant metabolic process.Recent studies showed that miRNA play a key role in secondary metabolic pathways in medicinal plants,while most of the pharmacological components in medicinal plants are produced through the secondary metabolic pathways.In addition,other reports showed that some of the miRNAs are highly stable in cross-kingdom gene transfer and regulation.Some of the miRNAs have been reported to participate in the inhibition of cancer through cross-kingdom regulation.However,no miRNA database specific for medicinal plants has been reported to date.Here,we reported the first version of MepmiRDB(medicinal plant microRNA database),which is freely accessible at http://mepmirdb.cn/mepmirdb/index.html.This database accommodates thousands of miRNA candidates belonging to 29 medicinal plant species,and provides users with several functional modules,including: the “Home” module(database home page,displaying database updates,and user access information),the “Sequence” module(which provides miRNA mature sequence,sequence and structure information of miRNA precursor),the “Expression” module(which provides information on the expression level of mature miRNAs in different tissues and organs,different growth conditions or treatment conditions),the “Interaction” module(which provides information on the interaction of miRNA controlled target genes at the protein level),the “Statistics” module(which provides a summary of 29 medicinal plant miRNA related statistical information),the “Search” module(which uses this module to search based on medicinal plant Latin names,miRNA families and miRNA sequences),the “Download” module(which provides 29 medicinal plant miRNA sequences,pri-miRNA sequences,pre-miRNA sequences,miRNA expression levels and downloads of target transcripts in the interaction network),and the “Document” module(which provides users with database help).All of these functional modules of MepmiRDB provide powerful basic data for researchers to investigate the sequence characteristics,regulatory mechanisms and biological functions of medicinal plant miRNAs.In the near future,the database will include the increasing number of relevant sequencing data in the public database,and may also include new medicinal plant species and new sequencing data types(such as RNA structure sequencing)to develop the second version of MepmiRDB.Besides,we will expand the database function(for example,adding miRNA upstream regulatory network information)in order to build a medicinal plant miRNA database with better user experience.