MicroRNAs As Potential Targets for Abiotic Stress Tolerance in Plants

Abstract

The microRNAs (miRNAs) are small (20–24 nt) sized, non-coding, single stranded riboregulator RNAs abundant in higher organisms. Recent findings have established that plants assign miRNAs as critical post-transcriptional regulators of gene expression in sequence-specific manner to respond to numerous abiotic stresses they face during their growth cycle. These small RNAs regulate gene expression via translational inhibition. Usually, stress induced miRNAs downregulate their target mRNAs, whereas, their downregulation leads to accumulation and function of positive regulators. In the past decade, investigations were mainly aimed to identify plant miRNAs, responsive to individual or multiple environmental factors, profiling their expression patterns and recognizing their roles in stress responses and tolerance. Altered expressions of miRNAs implicated in plant growth and development have been reported in several plant species subjected to abiotic stress conditions such as drought, salinity, extreme temperatures, nutrient deprivation, and heavy metals. These findings indicate that miRNAs may hold the key as potential targets for genetic manipulations to engineer abiotic stress tolerance in crop plants. This review is aimed to provide recent updates on plant miRNAs, their biogenesis and functions, target prediction and identification, computational tools and databases available for plant miRNAs, and their roles in abiotic stress-responses and adaptive mechanisms in major crop plants. Besides, the recent case studies for overexpressing the selected miRNAs for miRNA-mediated enhanced abiotic stress tolerance of transgenic plants have been discussed.

Stress‐induced evolution of herbicide resistance and related pleiotropic effects

“…Stress resulting from abiotic sources including several herbicides induces rapid ROS generation, which in turn impacts multiple pathways and cellular components . SAR and systemic acquired acclimation are characterized by the constitutive, heritable upregulation of genes/enzymes for redox maintenance, xenobiotic metabolism, and other protective pathways, likely as a result of rapid yet persistent changes in abiotic stress‐specific transcription factors and non‐coding RNAs . Similarly, stress‐induced changes in protein PTMs like phosphorylation and cysteine oxidation modify enzymatic and regulatory activities, allowing plants to rapidly adjust carbon flux .…”

“…4,17 SAR and systemic acquired acclimation are characterized by the constitutive, heritable upregulation of genes/enzymes for redox maintenance, xenobiotic metabolism, and other protective pathways, 18,19 likely as a result of rapid yet persistent changes in abiotic stress-specific 20 transcription factors and non-coding RNAs. 21 Similarly, stress-induced changes in protein PTMs like phosphorylation and cysteine oxidation modify enzymatic and regulatory activities, allowing plants to rapidly adjust carbon flux. 22,23 Plant transcriptome, proteome, and PTM changes caused by herbicide stress are quite similar to those resulting from abiotic and biotic stresses, [24][25][26][27][28][29][30][31] supporting the existence of the SAHR phenotype proposed here.…”

Contemporary Understanding of miRNA-Based Regulation of Secondary Metabolites Biosynthesis in Plants

“…These mature miRNAs are then loaded into the RISC complex to bind mRNAs for cleavage (Jones-Rhoades et al, 2006). miRNAs are well-known molecules for their role in regulating various plants processes under biotic and abiotic stresses (Gupta et al, 2014a,b; Shriram et al, 2016). Recently, various reports suggested their roles in regulating the biosynthesis and accumulation of secondary metabolites in plants (see review Bulgakov and Avramenko, 2015).…”

Improving Plant Water Use Efficiency through Molecular Genetics

“…These small RNAs regulate gene expression via translational inhibition. In recent years, research has mainly aimed to identify plant miRNAs, responsive to single or multiple environmental factors, profiling their expression patterns and determining their roles in stress responses and tolerance [28]. In fact, many altered expressions of miRNAs have been reported in several plant species subjected to abiotic stress conditions such as drought, salinity, extreme temperatures and heavy metals.…”