MicroRNAs and their role in plants during abiotic stresses

Abstract

Abiotic stresses have been considered as the growth-limiting factors affecting plants. Nutrient deficiency, drought, salinity, cold, submergence, and hypoxia are some of the severe types of abiotic stresses. Interdisciplinary research has been carried out to find stress-regulating mechanisms. MicroRNAs (miRNAs) are the newly discovered, 18–24 nucleotides long molecule of the genome. They have been considered as the key players against plant stress. They have been identified in plants, animals, humans, and even microbes. miRNAs have been shown to regulate various stress-responsive genes, proteins and transcription factors, thus helping to counteract adverse conditions. Various stress-inducible miRNAs have been identified and well characterized. Most of these miRNAs have been conserved among plants. This conservative nature has become the basis of development of computational methods of miRNA identifications, in additional to the traditional cloning approach. Presence of computational strategy has further simplified the miRNA prediction. Using this approach various stress-responsive miRNAs have been predicted, annotated and functionally validated from cotton, grapes, rice, maize, and soyabean. This chapter reviews the expanding world of miRNAs, methods unveiling miRNAs from various organisms, and specifically stress-induced miRNAs.