Wheat is one of the most important food sources on Earth. MicroRNAs (miRNAs) play
important roles in wheat productivity. To identify wheat miRNAs as well as their expression profiles
under drought condition, we constructed and sequenced small RNA (sRNA) libraries from the leaves
and roots of three wheat cultivars (Kukri, RAC875 and Excalibur) under water and drought conditions.
A total of 636 known miRNAs and 294 novel miRNAs were identified, of which 34 miRNAs were
tissue- or cultivar-specific. Among these, 314 were significantly regulated under drought conditions.
miRNAs that were drought-regulated in all cultivars displayed notably higher expression than those
that responded in a cultivar-specific manner. Cultivar-specific drought response miRNAs were
mainly detected in roots and showed significantly different drought regulations between cultivars.
By using wheat degradome library, 6619 target genes were identified. Many target genes were
strongly enriched for protein domains, such as MEKHLA, that play roles in drought response.
Targeting analysis showed that drought-downregulated miRNAs targeted more genes than droughtupregulated miRNAs. Furthermore, such genes had more important functions. Additionally, the
genes targeted by drought-downregulated miRNAs had multiple interactions with each other, while
the genes targeted by drought-upregulated miRNAs had no interactions. Our data provide valuable
information on wheat miRNA expression profiles and potential functions in different tissues, cultivars
and drought conditions