Identification and characterization of drought-induced long noncoding RNAs (DRILs) in rice

Long noncoding RNAs (lncRNAs) act as transcriptional regulators in plants and animals. To date, they have been reported to regulate various biological processes, such as phosphate homeostasis, grain yield, and fertility in rice (Oryza sativa L.). However, the lncRNAs involved in abiotic stress responses remain poorly identified in rice. In this study, we analyzed the expression profiles of lncRNAs using public rice transcriptome datasets derived from abiotic stress-treated samples. We found that the expression of thousands of rice lncRNAs was significantly altered in the shoot and root tissues under different abiotic stresses (drought, high salinity, low temperature, and abscisic acid). We selected six novel drought-induced lncRNAs (DRILs, specifically DRIL1 to DRIL6) for further study. Real-time polymerase chain reaction analysis revealed the differential expression patterns of these DRILs under various stress conditions. The expression of abiotic stress-responsive genes was upregulated in the protoplasts by transiently overexpressed DRIL1 and DRIL4. Therefore, DRILs may be involved in the transcriptional regulation of abiotic stress-responsive genes in rice.