Identification and Characterization of Rice Circular RNAs Responding to Xanthomonas Oryzae pv. Oryzae Invasion

Abstract BackgroundThe emerging role of circular RNAs (circRNAs) in various biological processes have advanced our knowledge of transcriptional and post-transcriptional gene regulation. The number and expression of plant circRNAs vary with species and treatments. However, the expression profile and the potential role of circRNAs during plant response to pathogen invasion are still elusive. ResultsIn this study, we identified 3517 circRNAs from PXO99A-infected rice leaves using the ribosomal RNA (rRNA) depleted RNA-Sequencing technique coupled with the CIRI2 and CIRCexplorer2 pipeline. Among them, 2994 (85.13%) circRNAs arised from the exons of their parent genes, 1214 circRNAs were previously unknown and 276 circRNAs exhibited differential expression profiles upon PXO99A infection over time. In addition, 31 differentially expressed circRNAs (DEcircRNAs) were predicted as the corresponding 121 miRNAs sponges. Functional analysis of both host genes and target mRNAs suggested that these identified circRNAs might play an important role in reprogramming rice responses to PXO99A invasion, mainly by mediating photorespiration, chloroplast, peroxisome and diterpenoid biosynthesis associated pathways.ConclusionThese results inferred a potential functional role of circRNAs in the regulation of rice immunity and provide novel clues for revealing the molecular mechanisms of rice-PXO99A interaction.