Micromics: A Novel Approach to Understand the Molecular Mechanisms in Plant Stress Tolerance

Abstract

MicroRNAs (miRNAs) are small endogenous non-coding RNAs with 20-22 nucleotides acts as the regulatory RNA. Since their discovery in model plant Arabidopsis, curiosity in understanding the function of plant miRNAs increased and regulatory role of miRNA are now being understood by researchers. The ability of miRNA to repress or induce the expression of several genes based on homology of few nucleotides has intrigued the scientific community. The detailed study has elucidated the step-wise biogenesis of miRNA across the species. Plants has evolved to respond to various external stimuli just by tinkering the expression of master regulators like transcription factors, miRNAs, etc. These master regulators further regulate the expression of several hundreds of downstream genes. There are several miRNAs has been identified as regulators of expression of various abiotic stresses viz., drought, cold, salt and high temperature and biotic stresses viz., viruses, bacteria, fungi, nematodes and insect pests. Additionally, paradigm shift in terms of sequencing technology and computational approaches led to identification of differentially expressed miRNAs for various stresses in plants. This led to the identification of thousands of miRNAs across the species which in turn helps to understand the molecular mechanisms involved in providing the stress tolerance. The present review discusses the mechanism of miRNA biogenesis, and role of identified miRNAs in regulating stress response in plants. The understanding of molecular mechanism of tolerance mediated through miRNA may help in improving the crop yields during various stresses.