MicroRNAs (miRNAs) are a class of small non-coding regulatory RNAs that regulate gene expression by guiding target mRNA cleavage or translational inhibition. Drought is a common environmental stress influencing crop growth and development. To date, it has been reported that a number of plant miRNA are involved in drought stress response. In this study, we comparatively investigated drought stress-responsive miRNAs in the root and leaf of bread wheat (Triticum aestivum cv. Sivas 111/33) by miRNA microarray screening. miRNA microarray analysis showed that 285 miRNAs (207 upregulated and 78 downregulated) and 244 miRNAs (115 upregulated and 129 downregulated) were differentially expressed in leaf and root tissues, respectively. Among the differentially expressed miRNAs, 23 miRNAs were only expressed in the leaf and 26 miRNAs were only expressed in the root of wheat growth under drought stress. Upon drought treatment, expression of miR159, miR160, miR166, miR169, miR172, miR395, miR396, miR408, miR472, miR477, miR482, miR1858, miR2118, and miR5049 were found to be significantly differentiated in bread wheat. The regulatory network analysis showed that miR395 has connections with a number of target transcripts, and miR159 and miR319 share a number of target genes. Drought-tolerant and drought-sensitive wheat cultivars showed altered expression pattern upon drought stress in terms of investigated miRNA and their target transcript expression level.
Keywords: Drought stress; Microarray; Triticum aestivum; microRNA.