A Nucleus-Localized Long Non-Coding RNA Enhances Drought and Salt Stress Tolerance

Long noncoding RNAs (lncRNAs) affect gene expression througha wide range of mechanisms and are considered as important regulators in manyessential biological processes. A large number of lncRNA transcripts have beenpredicted or identified in plants in recent years. However, the biologicalfunctions for most of them are still unknown. In this study, we identified anArabidopsis (Arabidopsis thaliana) lncRNA, DROUGHT INDUCEDlncRNA (DRIR), as a novel positive regulator of the plantresponse to drought and salt stress. DRIR was expressed at alow level under nonstress conditions but can be significantly activated bydrought and salt stress as well as by abscisic acid (ABA) treatment. Weidentified a T-DNA insertion mutant, drir^D, which hadhigher expression of the DRIR gene than the wild-type plants.The drir^D mutant exhibits increased tolerance todrought and salt stress. Overexpressing DRIR in Arabidopsisalso increased tolerance to drought and salt stress of the transgenic plants.The drir^D mutant and the overexpressing seedlingsare more sensitive to ABA than the wild type in stomata closure and seedlinggrowth. Genome-wide transcriptome analysis demonstrated that the expression ofa large number of genes was altered in drir^D andthe overexpressing plants. These include genes involved in ABA signaling, watertransport, and other stress-relief processes. Our study reveals a mechanismwhereby DRIR regulates the plant response to abiotic stress bymodulating the expression of a series of genes involved in the stress response.