The Study of microRNAs expression pattern involved in drought stress tolerance in ancestors and wild-domestic relatives of wheat

MicroRNAs are small non-coding molecules that regulate the expression of genes through mRNA digestion and/or translation inhibition. By accurately regulation the expression of the genes, these molecules allow the plant to respond appropriately to the changes in growth stages or environmental conditions. In this study, the miRNA159, miRNA160, miRNA398, and the miRNA398 targeted gene (CSD) were investigated in six species belonging to the Triticum and Aegilops species, along with the susceptible (DARYA) and tolerant (SIRVAN) check cultivars under drought (FC=25%) and non-stress (FC = 100%) conditions using real-time PCR. The qRT-PCR analysis showed that all three miRNAs had a significant (P≤0.01) increase in expression under drought stress. The highest expression of miRNA159, miRNA160, miRNA398, and CSD gene was observed in the species Ae.tauschii, T.urartu, T.durum, and T.durum, respectively. By the mean comparing of species × stress interaction, the highest expressions were observed in the three species T.durum, T.urartu and Ae.tauschii for all three miRNAs under drought stress. Also, the highest increase in CSD expression under drought stress was observed in T.urartu, T.durum and Ae.tauschii equal to 6.62, 6. 21 and 0.63 fold in compared to the non-stress condition, respectively. It was concluded that the species T.urartu, T.durum and Ae.tauschii due to their superiority in terms of containing miRNAs causer tolerance, could be suitable candidates for bread wheat germplasm enrichment and breeding to drought stress tolerance.