Conclusion and future directions
Rice as a major food crop is constantly challenged by various biotic stresses including fungal, bacterial, viral, nematodes and insects. These stresses cause considerable yield loss globally. Rice has developed innate immunity to fight with pathogens and insect pests. In recent years, miRNAs have been identified as potential molecular players for regulating the biological processes including rice immunity. It is indispensable to know the nature of regulation and target genes of miRNAs to achieve resistance response in plants against pathogens. The advancement in genomics tools offers a great opportunity to identify more plant miRNAs involved in biotic stresses. It is clear that immune-responsive miRNAs orchestrate the complex regulatory network controlling important agronomic traits. Exploitations of these miRNAs could be useful in breeding resistant varieties having improved agronomic traits without severe yield penalty. High-throughput RNA sequencing of plants exposed to pathogens will effectively lead to the identification of new miRNAs associated with disease and pest resistance. Once the specific roles of the miRNAs and target genes are identified, it would be possible to engineer them with genome-editing technologies. Site-specific mutagenesis of target genes impairs the cleavage by miRNA, which allows the development of transgenic plants with disease and insect resistance. Also, the modified miRNAs could be part of the potential resources for breeding elite crop varieties with resistance to various biotic stresses.