Genome-wide identification of cold-responsive and new microRNAs in Populus tomentosa by high-throughput sequencing

► We compared RNA libraries from cold-treated or control poplar by Solexa sequencing. ► Sequence analyses identified 144 conserved miRNAs and 29 new miRNAs. ► Differential expression analysis revealed 30 cold-responsive miRNAs. ► Gene expression profiles were validated by qRT-PCR analyses. ► We discuss the functions of some cold-responsive/new miRNAs to clarify their roles.