[Mining and characterization of miRNAs closely associated with the pathogenicity in tomato]

MicroRNAs (miRNAs) are a class of small endogenously RNA with an approximate length of 22nt which are known to be ubiquitous in eukaryotes. More importantly, miRNAs are key regulators of gene expression in eukaryotic cells through the degradation of target mRNA. The investigation on miRNAs in tomato that is an important model plant has made a great progress in recent years. Herein, by collecting the reported literature and miRBase, we found that 34 miRNAs in tomato are closely associated with pathogenicity. Subsequently, we predicted their target genes through bioinformatics approaches and built a disease-related regulatory network of miRNA and its target genes using Cytoscope program. This has led us to identify 13 miRNAs that are closely associated with pathogenicity in tomato from which we selected miR169, miR482, miR5300, miR6024, miR6026 and miR6027 for further analysis based on the association between miRNAs and the number of target genes. Lastly, we performed the analysis of target gene, promoter and real time quantitative PCR verification for these 6 miRNAs. Our study may pave the way for future in-depth analysis of biological action of miRNAs.