Role of abiotic stress responsive miRNAs in Arabidopsis root development

Abiotic stresses like drought, extreme temperature, and lack of sufficient water or nutrients adversely affect plant growth and productivity. The physiological responses of higher plants to the environmental stresses are largely influenced by the root system, which can quickly modulate its developmental pattern under changing water, nutrient, and temperature, as an adaptive response. Protein coding genes, phytohormones and microRNAs (miRNAs) are among the key players which imparts crucial intrinsic role in shaping the root development and its environment adaptive growth pattern. Among these factors, miRNAs belong to a class of small non-coding RNAs of 21-24 nucleotides in length, which regulates various aspects of plant growth and development by negatively regulating their target genes through either transcriptional cleavage or translational inhibition. Although many miRNAs have been identified to be differentially regulated under various abiotic stress conditions, only a limited number of them have been characterized, due to the complex nature of its regulation. However, some of the miRNAs, such as miR156, miR165/166, miR169 etc., have recently been shown to be involved in both abiotic stress response and root development, indicating the diverse role of miRNA mediated gene regulation. The field of miRNA mediated gene regulation is dynamically expanding and more miRNAs are being characterized for their function. Current review focuses on miRNAs that are differentially regulated by major abiotic stresses as well as are involved in root development in Arabidopsis thaliana. We highlight their role in regulation of multiple and diverse aspects of developmental and physiological processes in Arabidopsis.