Identification of circular RNAs in tea plant during Helopeltis theivora infestation

Abstract

The tea mosquito bug (TMB) or Helopeltis theivora has been reported as a significant tea pest that causes major tea crop loss. Circular RNAs (circRNAs) are a newly discovered group of the non-coding RNA (ncRNA) and are known to function in gene regulation process. Tea plant (Camellia sinensis) has not been explored for the detection of circRNAs during pest infestation. This is the first report of circRNAs identified in C. sinensis infested by a sap-sucking insect H. theivora. In total, we identified 709 circRNAs in six RNA-seq libraries. Analysis of the differential expression pattern revealed that 34 circRNAs got upregulated/downregulated in response to H. theivora attack. Functional annotation and enrichment analysis of the differentially expressed circRNAs showed that the circRNA-target genes were enriched in biological pathways like “tryptophan metabolism”, “biosynthesis of secondary metabolites”, “porphyrin metabolism”, “nucleocytoplasmic transport”, “N-glycan biosynthesis” etc. miRNA-mediated interaction analysis of the circRNAs also showed that 17 differentially expressed circRNAs could also act as “sponges” thus masking the miRNA-mRNA binding and subsequently repressing mRNA cleavage. These differentially expressed circRNAs were predicted to have the capacity to behave as endogenous target mimics (eTMs) for potential genes like aspartyl protease, phospholipase, lectin receptor etc.