Unravelling the Epigenetic Roles of Long Non-Coding RNAs in Plant Drought Resistance.

Drought stress is one of the most severe abiotic constraints limiting plant growth, productivity, and global food security, with its impact intensifying under climate change. Plants adapt to drought through complex physiological, transcriptional, and epigenetic regulatory networks. Among these, long non-coding RNAs (lncRNAs) have emerged as critical regulators that integrate transcriptional control with chromatin-level modulation. Once considered transcriptional noise, lncRNAs are now recognised as dynamic molecular regulators that fine-tune drought-responsive gene expression through chromatin remodelling, histone modifications, DNA methylation, RNA-directed DNA methylation (RdDM), and lncRNA-microRNA crosstalk. These mechanisms regulate key adaptive pathways, including abscisic acid (ABA) signalling, reactive oxygen species (ROS) homeostasis, osmotic adjustment, and root system plasticity. Emerging evidence further highlights the role of lncRNAs in epigenetic stress memory, enabling plants to maintain a primed transcriptional state and respond more efficiently to recurrent drought episodes. This review summarises recent advances in the epigenetic functions of lncRNAs in plant drought adaptation, with particular emphasis on chromatin dynamics, stress memory, and lncRNA-mediated regulatory networks. We also discuss insights from integrated omics approaches and highlight the translational potential of drought-responsive lncRNAs for developing climate-resilient crops.