BB- Bacterial blight, BPH-Brown planthopper, RRSV- Rice ragged stunt virus, RSV- Rice stripe virus
Figure Legends .
Figure 1 A simplified mechanism showing the role of miRNAs in the immune response of rice. The left half plane indicates an overview of the miRNAs that are responsive to fungal pathogens and insect, while the right half plane shows the miRNAs involved in resistance to bacterial and viral diseases. The miRNAs written in blue and red denote positively and negatively regulated miRNAs, respectively.
Figure 2 Model depicting the possible roles of miRNAs and secondary siRNAs (phasiRNA) in the regulation of R-genes . (A) In normal case, constitutive and unregulated expression of R-genes result in high fitness costs; (B) The MIR loci produce miRNA transcripts that are processed to mature miRNAs. The AGO1-miRNA binds to PHAStranscripts produced from coding region of PHAS loci and cleaved in sequence-specific manner. SGS3 and RDR6 converts the single stranded RNA to long double stranded RNA which is processed byDCL4 to phased siRNA (phasiRNA). AGO1/7- phasiRNA guides to cleavage of R gene transcripts and maintain the basal level expression of R gene to achieve optimized defence and plant fitness. Abbreviation: R genes-resistance genes, AGO1-ARGONAUTE 1 ,SGS3 -SUPPRESSOR OF GENE SILENCING 3 , RDR6- RNA-DEPENDENT RNA POLYMERASE 6 , DCL4- DICER-LIKE 4.
Figure 3 The network architecture showing involvement of different immune-responsive miRNA in various agriculturally important traits and abiotic stresses