Systematic Characterization of Long Non-Coding RNAs and Their Responses to Drought Stress in Dongxiang Wild Rice

Long non-coding RNAs (lncRNAs) play important roles in response to various biotic and abiotic stresses. So far, systematic identification and characterization of lncRNAs have been reported in a few model plant species and major crops, but their roles in abiotic stress response have not yet been reported in common wild rice (Oryza rufipogon). Dongxiang wild rice (DXWR) possesses a high degree of drought resistance and has been well recognized as a precious genetic resource for drought resistant rice breeding. We presented the reference catalog of 1 655 novel lncRNA transcripts in DXWR using strand-specific RNA sequencing and bioinformatics approaches. Meanwhile, a total of 1 092 lncRNAs were determined as differentially expressed lncRNAs under drought stress. Quantitative real-time PCR results exhibited a high concordance with RNA sequencing data, which confirmed that the expression patterns of lncRNAs based on RNA sequencing were highly reliable. Furthermore, 8 711 transcripts were predicted as target genes of the differentially expressed lncRNAs. Functional annotation analysis based on Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases showed that the target genes were significantly enriched in cellular and metabolic processes, cell part, binding and plant hormone signal transduction, as well as many other terms related to abiotic stress resistance. These results expanded our understanding of lncRNA biology and provided candidate regulators for genetic improvement of drought resistance in rice cultivars.