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.