Upstream Regulatory Elements, Potential Targets and Expression Patterns of Three Drought Responsive miRNAs in Two Grapevine Cultivars

MicroRNAs (miRNAs), as a group of non-coding small RNAs, play key roles in regulating the growth, development and response of plants to various stresses. In this study, the expression patterns of three drought responsive miRNAs (miR159c, miR160a,b and miR169v) were compared in both drought tolerant (Yaghuti) and drought sensitive (Bidanesefid) grapevine cultivars using qRT-PCR under drought stress conditions. For identification the potential regulatory elements in the promoter regions of investigated miRNAs, the upstream sequences of their pre-miRNAs were analyzed using PlantCARE database. Drought related motifs such as ABREs and ABSs were identified in the regulatory regions of investigated miRNAs. Three transcription factors related to Auxin and ABA signaling were identified as the most important target genes for investigated miRNAs. The expression patterns of studied miRNAs were different affected from miRNA kind and grapevine cultivar. So, the expression of miR159 remained unchanged in Bidanesefid and increased in Yaghuti cultivar under drought stress condition, but the expression of miR160 and miR169 changed reversely in both cultivars. Cultivar dependent expression showed that miRNA responses to drought stress are also different among very relative genotypes with different drought susceptibility. Generally, considering the role of the potential target genes of investigated miRNAs, it seems that the change in the expression of evaluated miRNAs ultimately leads to the better tolerate of drought stress in Yaghuti cultivar.