The research concluded that, currently miRNAs are taken as the most crucial regulators of gene. Until now, there is a significant progress has been made plant miRNAs analysis and characterization, with large amount of research conclusions in miRNA’s important function in crops. The review summarizes that several findings that contribute miRNA and its agricultural and economic importance [7]. The small nucleic acids regulate different environmental stresses also influences the growth of plants, the signaling of hormones, reproductive and vegetative phase changes along with the responses in homeostasis and signal transduction pathways. A few studies concluded that miRNA of crops shows in molecular regulations of defense and immune responses of plant. For the enhancement in the agricultural properties of plants and crops, the genetic engineering targets the modification of miRNA [35, 27].
The manipulation of miRNA and its expression levels focus on the responses of plants against pathogens, parasites and environmental stress which enhances it growth, for this purpose several transgenic approaches such as over expression, expression specific to tissues, stress-induced, artificially target mimic etc., are focused on important miRNAs [47].
In such cases the miRNA act as positive regulators of stress that suppress the corresponding messenger RNA which leads to the improvement of plants which causes an undesirable effect in the native target genes. In cases when the target genes show a desirable effect then the miRNA acts as negative stress regulators which leads to over expression or artificial target mimics of the target genes [94]. Even though its feels like successful the practical application of the miRNA crops is challenging in agronomics as the complexity of the multiple genetic traits requires tuning of different genes in various stages of the development of plants. For the future crop improvement, the above-mentioned methodologies and a detailed analysis on the miRNA-based regulation of target in crops and plants will benefit the future strategies and design. The over expression of the miRNA and the knockout of important genes leads to same phenotypes and can lead to the reduction of the miRNA is another major [95].
The miRNA activity regulates and act as a efficient tool to relate the activities if microRNA families and engineering of plants gene expression and this experiment offer a chance that can alter the sequence of decoy sites of miRNA that enhances the inactivation of miRNA and its targets also affects the production of plant phenotypes. But the major challenges faced is of false positive outcome by off- type effects of due to inactivation of miRNA, the action and communication between the miRNA and its decoy are very complex and that can also lead to plants losing its stability [96].
The latest invasion of biochemistry and physiology has a special focus in GE and transgenic technology has several uses in production of microorganism which includes plants, microorganism and animals. The augmentation via genetic alteration has influenced several crops. The foods that are genetically modified have much benefits such as tolerance towards salinity, resistance towards insects and high harvest. Genetically modified foods have numerous acts on health on human, these foods have both good and bad effects, which can be direct effect on the human that is consuming it or can be wider impacts such as in food chain that includes several other organisms.
For instance, if the expression of a miRNA or the targeted gene is changed, it may result in unacceptable pleiotropic changes in the developmental and morphological characteristics of that particular plant species. Hence, it is important to realize the miRNA regulation method in growth and development of plant or its reaction to different stresses. This will ease the pattern of procedures which are satisfying and thus results in the wish for traits but with limited trade-offs when it comes to modifies crops.