miRNA expression patterns of Triticum dicoccoides in response to shock drought stress.

Drought is a major environmental stress factor that affects plant growth and development worldwide. Wild emmer wheat (Triticum turgidum ssp. dicoccoides), the ancestor of domesticated durum wheat (Triticum turgidum ssp. durum), has great potential for improving the understanding of the wheat drought response. MicroRNAs (miRNAs) are a recently discovered class of gene expression regulators that have also been linked to several plant stress responses; however, this relationship is just beginning to be understood. miRNA expression patterns of drought-resistant wild emmer wheat in response to drought stress were investigated using a plant miRNA microarray platform. Expression was detected to be 205 miRNAs in control and 438 miRNAs in drought-stressed leaf and root tissues. Of these miRNAs, the following 13 were differentially regulated in response to drought: miR1867, miR896, miR398, miR528, miR474, miR1450, miR396, miR1881, miR894, miR156, miR1432, miR166 and miR171. Regulation of miRNAs upon 4 and 8 h drought stress applications observed by qRT-PCR. Target transcripts of differentially regulated miRNAs were computationally predicted. In addition to miRNA microarray study, five new conserved T. turgidum miRNAs were identified through a homology-based approach, and their secondary structures and putative targets were predicted. These findings both computationally and experimentally highlight the presence of miRNAs in T. dicoccoides and further extend the role of miRNAs under shock drought stress conditions.