Welcome to the plant microRNA database (PMRD) homepage! MicroRNAs play an essential role in regulating plant growth and development and recently research in microRNAs has made great progress. With whole genome sequence available in the plants such as Arabidopsis thaliana, Oryza sativa, Populus trichocarpa, Glycine max, etc., it is necessary to develop a plant microRNA database. Our PMRD try to integrate the available large information of plant microRNAs data, consisting of microRNA sequence and their target genes, secondary dimension structure, expression profiling, genome browser, etc.