MicroRNAs (miRNAs) are naturally occurring, highly conserved families of transcripts (18-25 nt in length) that are processed from larger hairpin precursors. Both plant and animal genomes encode miRNAs, and to date, there are over 4000 mature miRNA transcripts annotated. Although miRNAs represent a relatively abundant class of transcripts, their expression levels vary greatly among species and tissues. Less abundant miRNAs routinely fail detection using technologies such as cloning, northern hybridization and microarray analysis. Here, we present a real-time quantification method for accurate, sensitive, and economical detection of plant miRNAs based upon the stem-loop RT primer approach using an miRNA-specific primer coupled with a stem-loop specific Universal ProbeLibrary (UPL) probe. This approach represents a highly specific, sensitive, and easy-to-apply system to detect miRNAs. more