Identification and investigation of microRNAs associated with drought stress in barley

Study of stress tolerance in barley can help for a better understanding of the genetic basis of drought stress tolerance mechanisms and lead to improve the genetic properties associated with drought tolerance through modern molecular genetic techniques. To this end, microRNAs associated with drought stress in barley leaf and root ESTs were analyzed in Nimruz and spantaneum barley genotypes. Bioinformatics databases were mined for relevant EST libraries and bioinformatics services were used for pre-processing and identify genes with different expressions among libraries. The expression profile of candidate genes was studied, by using Real time-PCR in a factorial-split plot design, including Nimruz as tolerant and Spontaneum as a drought sensitive in pots with three replications. Sampling time was also considered at 0, 24 and 72 hours after drought stress as sub factor. Results of this study led to identification of three highly-expressed miRNAs (ath-miR414, os-miR2102-5p and osa-miR414). The expression analysis showed that miR414 and miR2102 expression was significantly (P< 0.05) increased in both genotypes in response to drought stress. After 72h in Nimruz and Spontaneum, the expression of miR414 reached 2.61 and 2-fold and the expression of miR2102 was 2.4 and 2.8-fold of that of control (Spontaneum at control condition at 0 times), respectively.