Prediction And Function Analysis Of MicroRNA And Target Genes In Potato

MicroRNAs (miRNAs) are a class of non-coding small RNAs with 21-23 nucleotide length. Increasing evidence has shown that miRNAs play multiple roles in biological processes, involved in the morphogenesis of root, stem, leaf and flower, signal transduction and environmental stress and so on. In recent years, hundreds of miRNA and its target sequence have been identified in plants by cloning method and bioinformatics method, but mainly in Arabidopsis thaliana, maize and some other model plants, and many of the functions of miRNA is not clear.Potato (Solarium tuberosum L.) is one of the world's food crops and vegetables, in which more than 80 potato miRNAs and their target genes have been obtained through the computational prediction. However, in comparison with other organisms, the miRNA genes identified for potato are still far from reaching saturation, and their biological functions are unknown. In this study, new potato miRNA were obtained by computational prediction, and target genes were identified in order to conduct purposeful use of miRNA genetic improvement of potato, so as to lay the theoretical foundation for the new of further developing high-quality, efficient and stress resistance of potato germplasm. The results are as follows:1. In the present paper, according to the conservative property of miRNAs in plant, a total of 32 novel miRNAs were identified from potato following a range of filtering criteria by using previously deposited miRNA sequences from Arabidopsis thaliana, Oryza sativa and other plant species to blast potato expressed sequence tags (EST), genomic survey sequence (GSS) and nucleotide databases, and removing the protein coding genes by on line software blastx. All the potential miRNA precursors can be folded into the typical secondary structure of miRNA family.2. Using the miRNAs sequences,100 target genes were identified by blasting the databases of coding protein using on line software miRU and miRU2. The genes encode protein involved in growth and development, metabolism, signal transduction, transcriptional regulation and stress responses.3. By RT-PCR experiments, the results showed that potato miR167b was found with stable expression in the bud, stem and root tissues, but did not express in the leaf tissue. MiR482b in potato bud, leaf, stem and root were expressed, which expressed in relatively high abundance in bud, stem and root, but in leaf tissue in very small amounts, which reflected the specificity expression of miRNAs in the tissue.