**1. Introduction**

Plants form an essential portion of the earth system and used by man as food, shelter, and a great source of medicine. Main threats to plant products and productivity are various human actions, biotic and abiotic stresses like soil toxicity, climate change, water stress, microbial pathogen, insects, herbivores *etc*. Global industrialization and increasing human population are two main factors that promote environmental changes and also enhance the demand for crop production. However, climate change and ever-increasing demand of plant products has the ability to modify the atmospheric properties and modify soils, which can make crop yield, development and growth more difficult. One of the important ways involves to enhance the yield and crop productivity is by using environmentally friendly plant protection measures [1]. Improvement in molecular biology and biotechnology identified the microRNAs role at post transcriptional level in controlling important secondary metabolites synthesis pathway [2]. This chapter gives a brief description on discovery and biogenesis of miRNA. On the basis of current research, it also describes the miRNA-based strategies used as potential tool for gene regulators in biofuel sources, beverages, cereals, fruits, fibers and economically important crops.

#### *Botany - Recent Advances and Applications*

Plants are sessile organisms, obstinately face adverse environmental perturbations termed as abiotic stresses, most important being drought, soil salinity, extreme temperatures, and heavy metals [3]. Abiotic stresses have become a major challenge due to their widespread nature and the devastating impacts on plant growth, yields and the quality of plant produce. However, plants have developed intricate mechanisms for sensing and responding to environmental changes [4]. To turn on protective mechanisms, plants trigger a network of genetic regulations including altered expression of large proportion of genes by transcriptional and/or translational regulations [5].
