Abstract
Several biotic (bacterial and viral pathogenesis) and abiotic stress factors like salt, drought, cold, and extreme temperatures significantly reduce crop productivity and grain quality throughout the world. MicroRNAs (miRNAs) are small (~22 nucleotides) non-coding endogenous RNA molecules which negatively regulate gene expression at the post-transcriptional level either by degrading the target protein-coding mRNA genes or suppressing translation in plants. Dirigent (DIR) gene protein plays a crucial role as they are involved to dictate the stereochemistry of a compound synthesized by other enzymes as well as in lignifications against biotic and abiotic stress. In plants, several miRNAs, as well as their targets, are known to regulate stress response but systematic identification of the same is limited. The present work has been designed for in silico identification of miRNAs against a total of sixty-one DIR genes in Oryza sativa Indica followed by target prediction of identified miRNAs through the computational approach and thereafter validation of potential miRNAs in rice genotypes. We systematically identified 3 miRNA and their respective DIR specific target gene in Oryza sativa Indica. The expression of these three miRNAs and their respective DIR specific targets were validated in rice seedlings subjected to five different abiotic stress conditions (heavy metal, high temperature, low temperature, salinity and drought) by quantitative Real-Time PCR (qRT-PCR). Expression analysis indicated that miRNA under stress conditions regulates the gene expression of the DIR gene in rice. To the best of our knowledge this is this is the first report in any organism showing the expression of ath-miRf10317-akr, and osamiRf10761-akr miRNAs in response to various abiotic stresses.