Comparative expression analysis of microRNAs targeting GRAS genes induced by osmotic stress in two contrasting wheat genotypes

Abstract

Abstract Background MicroRNAs (miRNAs) are important nonprotein-coding genes in plants which participate in in almost all biological processes during abiotic and biotic stresses. Understanding how plants respond to various environmental conditions requires the identification of stress-related miRNAs, and recent years there has been an increased interest in studying miRNA genes and miRNA gene expression. Drought is one of the common environmental stresses limiting plant growth and development. To understand the role of miRNAs in response to osmotic stress, stress-specific miRNAs and their GRAS gene targets were validated. Results In this study, we analysed comparative expression patterns of the ten stress-responsive miRNAs and targeting GRAS genes involved in osmotic stress adaptation in order to understand the regulation behaviour of abiotic stress and miRNAs in two contrasting wheat genotype C-306 (drought tolerant) and WL-711 (drought sensitive). Three miRNAs were found to be up-regulated in response to stress, whereas seven miRNAs were found to be down-regulated as a result of the study. In contrast to miRNA, it was also discovered that GRAS genes as their targets were up-regulated during osmotic stress. Furthermore, miR397 and its target GRAS53 were shown to be down-regulated at distinct time intervals while being unaffected by osmotic stress. Variation in the level of expression of studied miRNAs in the presence of target genes provides a likely explanation of miRNA-based abiotic stress regulation. A regulatory network of miRNA and their targets revealed that fourteen miRNA interact with 55 GRAS targets from various subfamilies that contribute in the plant growth and development. Conclusions These results provide evidence for temporal and variety-specific differential regulation of miRNAs and their targets in wheat in response to osmotic stress and could help in defining the potential roles of miRNAs in plant adaptation to osmotic stress in future.