RNA- and miRNA-interference to enhance abiotic stress tolerance in plants

In response to rapidly changing environment, plants have employed a plethora of mechanisms that provide phenotypic plasticity and allow fine-tuning of stress-response actions. Advances in molecular biology have made substantial progress in identification of genomic regions and underlying mechanisms that influence transcriptional and post-transcriptional regulation of abiotic stress pathways. In plants, small RNAs (sRNAs) have evolved through a series of pathways and contributed to the complexity of these molecules and play an essential role in the regulation of stress response activities. It has been shown that one way of plant response to deal with environmental stress is by modulating gene expression through the activity of small RNAs. Small, non-coding RNAs (ncRNAs) belong to a distinct class of regulatory RNAs and control a variety of biological processes in plants and other systems. The ncRNAs, particularly microRNAs (miRNAs) and (siRNAs) have emerged as an essential regulator of plant abiotic stress response that are the driving molecules of RNA interference (RNAi) and ensure up- and down-regulation of the target genes, which participate in important biological processes. Thus, RNA- and miRNA- interference has become a novel strategy for crop improvement. This review highlights the regulatory roles of miRNAs and siRNAs in the adaptive response to various plant abiotic stresses.