A first comparison of miRNA profiles of Antarctic Deschampsia antarctica ecotypes with Triticum aestivum upon single or combined salt and drought stresses.

Deschampsia antarctica, one of the two vascular plants capable of surviving the extreme conditions of Antarctica, provides a unique opportunity to study plant adaptation to severe abiotic stress. Despite its resilience, there is a paucity of molecular-level research on this species, particularly concerning the role of microRNAs (miRNAs) in stress responses. This study aims to fill this gap by investigating the physiological, biochemical, and molecular responses of D. antarctica under salt, drought, and combined stress conditions, and comparing these responses to those of Triticum aestivum (cv. Reis). Using next-generation sequencing, we identified 161 novel, among these 77 were stress-related and 1170 known wheat consensus miRNAs in the genomes of different D. antarctica ecotypes from Antarctica. Physiological and biochemical analyses revealed that D. antarctica maintained more effective water use and lower oxidative stress respective to T. aestivum. Furthermore, miRNA profiling highlighted differential expression patterns, with conserved responses observed among D. antarctica ecotypes. Validation of miRNA-target gene interactions through qRT-PCR confirmed that miRNA expression levels varied relative to target gene expression. These findings emphasized the importance of miRNAs in stress adaptation and highlighted the potential of D. antarctica as a model for enhancing stress tolerance in crops.