Transcriptome-wide identification and profiling of miRNAs in a stress-tolerant conifer Sabina chinensis

miRNAs are important regulatory components involving in many biological processes, including plantdevelopment, vegetative and reproductive growth, and stress response. However, identification and characterization of miRNAs still remain limited for conifer species. In this study, with deep sequencing, we obtained1,314,450 unique reads with 18–30 nt length from a stress-tolerant conifer, Sabina chinensis. We identified 37conserved and 103 novel miRNAs, their unique characteristics were further analyzed, and 10 randomlyselected were validated by qRT-PCR. Through miRNA target predictions and annotations, we found miRNAmay have several targets as well a target could be regulated by several miRNAs, and a total of 2,397 mRNAswere predicted to be targets of the 140 miRNAs. These targets included not only important transcription factorssuch as auxin response factors, but also indispensable non-transcriptional factor proteins. Pathway-basedanalysis showed that S. chinensis miRNAs are involved in 172 metabolic pathways, of which 3 were discovered in adaptation-related pathways, indicating their possible relevance to the species’ stress-tolerancecharacteristics. This study is expected to lay the foundation for exploring the regulative roles of miRNAs indevelopment, growth, and response to environmental stresses of S. chinensis.